Create Electronic signature Word Android

Portable Document FormatThe .pdf files can only be open with pdf reader softwares like the most popular signNow and Foxit Reader. These applications are also available for Android and iOS.Well, we mostly create pdf files for electronic signatures and to make it more safer.As we know, most of the companies uses their unique font style in their documents and if the company send a letter to any of their associates by an email in a Ms Word format. Their associates might find the document in different font style because they are not using the same font style. So pdf documents are not editable which makes them more portable to share. Pdf files maintain the same font style and style in which it was created.You can check by yourself by making documents in a ms word format and pdf format.If u wanna know how to create pdf documents u must google it.

Esignly is an e signature app which provides proficient and innovative e signature solutions to its customers. Esignly is a product of Cyber Infrastructure (P) Limited and offers a line of services right from creating, signing, and sending to tracking and managing documents online.This electronic signature app provides its user with a single account which can le logged in from any electronic device and access it anytime.Here is a list of features provided this app that proves Esignly’s reputation in the industry as an admirable Digital Signature Tool-API- Helps in doing eSignatures swiftly ...

Edit: I wrote this answer for “must have Android apps” but these are same apps which have changed the way I used to live my life. Each and every App has helped me in one or the other way. I hope you will also find them helpful and a bit life changing. So here is the list: 10. Psiphon For those who use WiFi with proxy settings. So Psiphon bypasses and tunnel the websites or app through a different IP Address. 9. Mirror It's a simple app to record your mobile screen. Based on the concept of CamStudio in PC where you can record your screen, Mirror offers recording of your Mobile screen. 8. NTES- National Train Enquiry System If you are from India and you want to know the running status, cancelled train (partial or fully), Live Station and other features, this App is a must have. 7. VOLT Simple but effective for those who want to learn new vocabulary. That's too obvious, then why not others? Coz here you get the “memory key” which helps you relate the words and easier to remember them. 6. Parchi It a note making app. But here’s a catch. You can view, review, edit and add right from your lockscreen without need to open the app. Isn't that amazing! I personally find this app very useful. 5. edX If you are student or a learner who wants learn something new everyday, and cannot afford to go in the prestigious institutions like MIT, Harvard University, Cambridge, IITM, etc ten it is a must have app. Enroll yourself in any course and Bazinga!! You are ready to learn from the most amazing professors. Similar to edX, we have Coursera. 4. Walnut Manage your expenses on your finger tips. Its easier then that. It shows you your monthly expenditure, ATM locations, bill remainders and many more features. Its a must have app. 3. CamScanner Everyone doesn’t own a scanner but most of us have camera. So click the pic, upload to CamScanner and voila you are done. You have the scanned copy of your documents, notes, Marksheet and upload them on your DigiLocker. 2. inshorts Till now you all must be knowing this app. The tagline is also simple “News in 60 words” and trust me it is worth having. In this “I don't have time” world, you need news to be fast and accurate so here it is. 1. DigiLocker If you have this app then you don’t need to carry your personal documents like driving license, Adhar card, voter ID card, or even your Marksheets. Keep them safe in actual locker and leave the rest to your DigiLocker. And the best part is that it is acceptable as the original ones at every governmental or non governmental institution because it is developed under Digital India initiative. That's it for the day. Thank you and Enjoy !!! Update 1: Today I came across two new apps which I found useful. Hope it would help you all. 1.Forest : Stay focused Features • A self-motivated and interesting way to help you beat phone addiction • Stay focused and get more things done • Share your forest and compete with friends • Track your history in a simple and pleasant way • Earn reward and unlock more tree species • Customize your whitelist : Leaving Forest and using apps in whitelist won’t kill your tree. 2. Swachh Bharat Toilet Locator Swachh Bharat Toilet Locator is specifically useful for Indians who're committed for Swachh Bharat. Update 2: So I am back with yet another interesting app for you all. And trust me it is worth hanving. You are bored just go through it and kaboooom !!! You are into a black hole. Enjoy the ride. 3. Curiosity It is the latest app I installed but got addicted to it. It’s exactly works like its name, generates a curiosity which inturn increases your knowledge. It covers a large field of scope from Humanity to science to faith and many more. This app deserves more snapshots but why to increase the length of my answer. Comment below if you think the list should be updated? Thank you.

Unobtainium: They just don't make it like that any more.Since the first tales of gods and myths, there have been legends of devices crafted, machines made, engines imagined that have been considered the strongest, most powerful, most durable devices in creation. It is the cornerstone of many such tales.And since everyone of them has some legend where their smiths created the ultimate weapon, comparing them is basically a fool's errand. So rather than engage in random and useless comparison, let's travel through myth, legend, storied lore, four colored wonders, as well as far-flung futures and see some of these mythically-indestructible materials or devices.Legendary Mythic MetalsOrichalcum (variously spelled orichalcon, orihalcon or orichalc): a metal first appeared in Plato's version of the Atlantis myth. The name means "mountain copper" in Greek, and it, indeed, often appears the color of copper or bronze. Orihalcum's properties vary heavily from source to source: sometimes its schtick is strength, sometimes it's high value, sometimes it's magic resistance, sometimes it's room-temperature superconductivity. Sometimes it floats.​Atlantis : a legendary city which was reputed to have sank beneath the waves in ancient times.Cold Iron (variously called cold steel, wrought iron, magnetic iron and so on) is the traditional bane of The Fair Folk. Precisely what constitutes cold iron varies from source to source, such as being forged without heat, forged by hand, being ferromagnetic, possessing trace amounts of iridium, literally being cold, and so on. In some legends being struck with iron had a poisonous effect on the Fey, in some, even being in the same area as cold iron could be dangerous.Adamant, any impenetrably or unyieldingly hard substance; a legendary stone of impenetrable hardness, formerly sometimes identified with the diamond.Origin of adamant: Middle English, Old French, Latin, 900 AD. before 900; Middle English < Old French adamaunt < Latin adamant-(stem of adamas) hard metal (perhaps steel), diamond < Greek,equivalent to adamant- verbal adjective of damân to tame, conquer; replacing Old Eng. athamans (< Medieval Latin) and Middle English aymont < Middle French aimant < Vulgar Latin *adimant- < LatinAdamant in the Bible(Heb. shamir), Ezek. 3:9. The Greek word adamas means diamond. This is not referred to, but corundum or some kind of hard steel. It is an emblem of firmness in resisting adversaries of the truth (Zech. 7:12), and of hard-heartedness against the truth (Jer. 17:1).​Legendary Indestructible WeaponsLegends abound with indestructible weapons. Here are just a few of the more well-known magical swords.​Excalibur:Having many names and sometimes confused with the Sword in the Stone, the legendary Excalibur was often referred to as a Blade of Light.Impossibly light and durable, having Excalibur and its attendant scabbard made a warrior a killing machine unable to die from his wounds.​Inspiration of Medieval Language & Literature: The Song of Roland (Batlle of Roncesvalles Pass, 778)​DurendalDurendal (most likely from the French "durer," "to endure") is the sword of Charlemagne's paladin Roland in the literary series known as the Matter of France.In The Song of Roland, Durendal is said to contain within its golden hilt one tooth of Saint Peter, blood of Saint Basil, hair of Saint Denis, and a piece of the raiment of the Blessed Virgin Mary, and to be the sharpest sword in all existence.Roland attempted to destroy the sword to prevent it from being captured by the attacking Saracens but Durandal proved indestructible, so he hid it beneath his body along with the oliphant, the horn used to alert Charlemagne.In the poem, Roland uses the sword to hold off a hundred-thousand-strong Muslim army long enough for Charlemagne's army to retreat into France.KusanagiKusanagi-no-Tsurugi (草薙の剣?) is a legendary Japanese sword and one of three Imperial Regalia of Japan. It was originally called Ame-no-Murakumo-no-Tsurugi (天叢雲剣?, "Sword of the Gathering Clouds of Heaven") but its name was later changed to the more popular Kusanagi-no-Tsurugi ("Grass Cutting Sword").Found in the tail of a great beast by the god Susanoo-no-Mikoto it was presented to the goddess Amaterasu to settle an old grievanceIn the reign of the Twelfth Emperor, Keikō, Ame-no-Murakumo-no-Tsurugi was given to the great warrior, Yamato Takeru as part of a pair of gifts given by his aunt, Yamato-hime the Shrine Maiden of Ise Shrine, to protect her nephew in times of peril.These gifts came in handy when Yamato Takeru was lured onto an open grassland during a hunting expedition by a tsignNowerous warlord. The lord had fiery arrows loosed to ignite the grass and trap Yamato Takeru in the field so that he would burn to death. He also killed the warrior's horse to prevent his escape.Desperately, Yamato Takeru used the Ame-no-Murakumo-no-Tsurugi to cut back the grass and remove fuel from the fire, but in doing so, he discovered that the sword enabled him to control the wind and cause it to move in the direction of his swing.Taking advantage of this magic, Yamato Takeru used his other gift, fire strikers, to enlarge the fire in the direction of the lord and his men, and he used the winds controlled by the sword to sweep the blaze toward them. In triumph, Yamato Takeru renamed the sword Kusanagi-no-Tsurugi (lit. "Grasscutter Sword") to commemorate his narrow escape and victory.​Super-metals of the DC Universe​KryptonianIn the Silver Age of the DC Universe, Krypton was one of most sophisticated worlds in the DC Universe. A world so incredible that anything created there was virtually indestructible once it was under a yellow sun. (Don't think about it. The writers of the era didn't and it was fine.)Superman rocket he came to Earth in was was undamaged upon traveling across space and it delivers baby Kal-el to Earth without a scratch despite its crash landing.Martha Kent was said to have unwoven the fabrics he was wrapped in and rewoven them into his only costume. The costume was indestructible except to Kal-El's heat vision, which was how she was said to have cut the material, when necessary.These two pages are from Superboy v1 #169, October 1970.In this version of the character, baby Kal-El was so hard on his clothing due to his powers manifesting as a child, he was unable to wear anything except materials woven from those fabrics. (I am not making this up.)This explanation was made as part of a series called the Superboy Legend. This was a common thing done during the period because the comics were both numerous and often had unconnected (and sometimes conflicted) stories. This was one of the early attempts to help readers keep up.This was not an imaginary story. It was written in the canon to explain how Superman's costume came to be nigh-invulnerable. The above pencil art is by Superboy artist at the time, Bob Brown, with inks by the famed Wally Wood. Some of the illustrations here, particularly the sequence where Pa shoots and blows up the blankets, are adapted from stories published in much earlier issues of Superboy.Since his costume and cape were practically indestructible, Superman's used his invulnerable cape in a number of ways in early comics.He would use his cape to protect people near him. In this case, molten lava didn't land on Miss Lane, which I am certain she considered a good thing.Superman could use it to hold dangerous materials, toxic chemicals or to protect innocents from a rain of bullets when a broad chest wasn't quite broad enough. It was pretty handy to have around when a nuclear weapon had to be contained, too.He also used it to protect passengers from the effects of friction from his passage through the atmosphere at super-speed. He would also wrap passengers, both to protect them and to maintain the anonymity of his Fortress of Solitude, in the Arctic.​Superman Airlines: It's fast. It's cheap. But the accommodations make "coach" seem absolutely spacious compared to flying "mummy-wrapped."Supermanium, named for its inventor, was introduced in World's Finest #41 (Jul-Aug 1949), a prison created to contain the menace of Brainiac.According to Superman (Volume 1) #167, Superman forged it out of the heart of a star, which implied its durability was related to its molecular density.It would also make it the heaviest prison anywhere since collapsed stellar matter would be incredibly dense and highly radioactive...​Supermanium's more famous appearance was in the emergency vehicle Superman created when the threat of losing his powers from a nearby red sun supernova required he create his most inauspicious vehicle, the Supermobile. Yes, it has robotic arms with super-strength and it can replicate Superman's vision powers and has an onboard computer and television.​This is the Supermobile. Don't think too much about it. You'll forget it eventually. Almost every comic reader has, at least up till now. Even Superman fans pretend it didn't happen.​From the isle of Themyscira​Amazonium was the name of a metal used for the construction of Wonder Woman's Bracelets of Submission. These bracelets, created by Aphrodite were to remind them of the cruel submission the Amazons suffered under Heracles. In the classic tales of Wonder Woman, binding the bracelets together removed an Amazon's abilities.​The bracelets have thus far proven indestructible and able to absorb the impact of incoming attacks, allowing Wonder Woman to not only deflect automatic weapon fire, energy blasts and other projectile weaponry (Wonder Woman Vol. 1 #52, 1952)​Speaking of Wonder Woman, her golden lasso was reforged from the Girdle of Hera and reputed to be all but indestructible. While the material used for its creation is never named, its magical powers include immediate submission to the will of the wielder, the ability to force the person entangled to tell the truth and the ability to change its length to whatever Wonder Woman needs it to be.In the current era of the DC Universe, (New 52) Wonder Woman is a demigod and her bracers are still indestructible (as well as a whole lot heavier) and used to bind her godlike powers, allowing her to remove them and become more powerful and more uncontrolled as long as they are removed.​New Wonder Woman is scary. Really, really scary.Modern depictions of Wonder Woman indicate her sword and shield are both god-forged weapons, made by the smith-god Hephaestus and are (by his admission, alone) indestructible. Granted, there is no way to tell for certain but all of his devices are incredible durable and in the case of Wonder Woman we have seen her use said armor and weapons against other powerful magical beings such as Ares and Hades to good effect. So we can safely assume a great degree of durability due to their magical enhancement and manufacture. Did I mention it was sharp enough to carve atoms apart?It can cut Kryptonians too. Ask Faora and Zod. I would say it’s plenty sharp if not completely indestructible.Thanagar​Nth Metal (also called ninth metal) is a special metal found in the DC Universe. Native to Thanagar, the home planet of Katar Hol and Shayera Thal. The material possesses a number of special abilities and can take on both mystical and technological properties depending on who's using it.Among the unusual properties of Nth metal is the ability to negate gravity, allowing a person wearing an object, such as a belt, made of Nth Metal to fly. In addition, Nth metal also protects the wearer from the elements and speeds the healing of wounds, increases their strength, and protects them from extremes in temperature.​Hawkgirl's mace emitted an energy field which disrupted technology and magical energies.In its animated appearance in Justice League and Justice League Unlimited, Nth metal is transuranic iron with an atomic number of 676, possesses innate anti-magical properties, is hyper-conductive and is able to invert mesons and gravitons. Hawkgirl could us it to disrupt magical attacks and magical beings.​Earth (You know what it looks like)Promethium is the name given to two metal alloys: "Depleted" and "Volatile" Promethium.Depleted promethium was invented and patented by Steve Dayton of Dayton Industries. Promethium alloyed with titanium and vanadium it forms a nearly-indestructible metal.​"But son, I made you out of promethium, the strongest man-made metal on Earth!" Okay, Cyborg didn't take to his condition very well in the beginning.The weapon-master, Arsenal (formerly Speedy, the archer sidekick of Green Arrow), wore protective armor which comprised depleted promethium armor. The metallic components of the Justice League member Cyborg (Victor Stone), are made from depleted promethium. Victor Stone's limbs were capable of exercising superhuman strength and durability.​He got better. He's a member of the Justice League. Attitude adjustment!"Volatile" Promethium is capable of absorbing energy in proportion to its mass without loss of efficiency. Depending on the volume of the material, it can be used to generate and absorb a near-limitless amount of energy.Both metals are seemingly difficult to manufacture and thus supplies are limited. Deathstroke, the Terminator, uses volatile promethium in his weapons and has been known to charge them before his missions adding to their deadly profile.30th Century, Legion of SuperheroesWelcome to the 30th century. So clean. So sterile. No trees, no grass. No soul...Inertron is a fictional metallic substance found in the DC Comics Legion of Super-Heroes universe. It is the hardest, densest substance in the DC universe, and is often used by the Legion of Super-Heroes in the 30th century. The first mention of inertron was in Adventure Comics #336.Inertron is frequently described as indestructible and impenetrable, but this applies to beings and technologies based in human strength norms. Kryptonians and Daxamites have been show to be able to break inertron if they push themselves to the limits of their strength.However, reinforced inertron structures (like prisons) can resist even their formidable strength. Karate Kid once managed to, using his formidable super-martial arts techniques, to break a set of shackles formed from inertron.A strange fact: Inertron has been eaten by 30th century residents of Bismoll of whom Matter-Eater Lad is a known representative of the species. As you can probably tell from his name, he is able to somehow, inexplicably, and I mean never to my scientific curiosity or satisfaction consume any kind of matter, at superhuman speed, without waste products, or surplus energy output while retaining a human shape in all overall appearance.The Silver Age was an age of wonders. You wonder what they were using. You wonder how long they were high. You wonder how these books made it past an editor with a straight face. An age of wonders...​A member of the Legion of Unfortunately Named Heroes, Matter-Eater Lad's signature power was eating anything between him and freedom.​Matter-Eater Lad once ate inertron. The most indestructible metal in the known universe. He also ate the indestructible, miraculous Miracle Machine. This was the first time he ate something that didn't agree with him.​See kids, even a lame power like matter-eating can come in handy to save the universe under the right conditions. I know this is what you're doing when you think of a superhero based on this idea. I look like this when I think about the Bismolleans.How do you imprison Bismolleans? Are they a society of perfectly well-adjusted non-criminal citizens?Do Bismolleans need toothbrushes? I mean do they even have teeth? What exactly happens from inside their gumline to their "digestive tract?"Do they use antacids, er...anti-radioactives when they have an upset "whatever passes for their super-nuclear furnace" region in their mouth?Screw that: What kind of atomic nightmare is taking place in side of Bismolleans? Are they most radioactive members of the United Federation of Planets?Why aren't we powering our star-cruisers on directed energy-Bismollean power supplies? (Besides the inhumanity and monstrous reality of such an incredibly powerful energy source running on garbage and Bismollean misery...) How do we know the UFP doesn't already run this way?​Charlton Universe (now a subset of the DCU)Shazamium, Marvelium and Sivanium: highly adaptable and mutable metal capable of storing fantastic levels of magical energy. Used in numerous schemes by the nefarious Dr. Sivana.The largest supply of this strange magical metal, was held by the wizard, Shazam. First appears in Captain Marvel #100.Ancient Earth TechHumans went from primitive stone tools to space age metallurgy over a period of 200,000 years.Those periods are often broken up into the Stone Age, the Bronze Age, the Iron Age and the Industrial Age, which takes the best of all of the previous technologies.I focused on weapons because that seems to be where human innovations almost always seem to be highly focused and result oriented. (Such a sad statement...)Weapons without MetalBronze Age Swords (Introduction)Iron Age swordsMaking Damascus SteelJapanese Swordsmithing​Modern MetallurgyModern metallurgy has taken the knowledge of previous eras and created using new discoveries on the periodic table to create new and harder and stronger metals than ever before.​Maraging steels are used in jet enginees and other technologies needing strength, durability and heat tolerance.Maraging steelsMaraging steels (a portmanteau of "martensitic" and "aging") are steels (iron alloys) that are known for possessing superior strength and toughness without losing malleability, although they cannot hold a good cutting edge. Aging refers to the extended heat-treatment process.These steels are a special class of low-carbon ultra-high-strength steels that derive their strength not from carbon, but from precipitation of intermetallic compounds. The principal alloying element is 15 to 25wt.% nickel.Secondary alloying elements are added to produce intermetallic precipitates, which include cobalt, molybdenum, and titanium.​Inconel Exhaust Manifold​InconelInconel is a family of austenite nickel-chromium-based superalloys. The name is a trademark of Special Metals Corporation, a wholly owned subsidiary of Precision Castparts Corp.Inconel alloys are oxidation and corrosion resistant materials well suited for service in extreme environments subjected to pressure and heat. When heated, Inconel forms a thick, stable, passivating oxide layer protecting the surface from further attack.Inconel retains strength over a wide temperature range, attractive for high temperature applications where aluminum and steel would succumb to creep as a result of thermally induced crystal vacancies. Inconel’s high temperature strength is developed by solid solution strengthening or precipitation strengthening, depending on the alloy.​An extremely hard metal, this tungsten rotary burr set is used to shape softer substances (meaning anything that isn't tungsten...) Tungsten carbide burr sets get excellent ratings from the craftsman crowd.​Tungsten carbideTungsten carbide (chemical formula: WC) is a chemical compound (specifically, a carbide) containing equal parts of tungsten and carbon atoms.In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed and formed into shapes for use in industrial machinery, cutting tools, abrasives, armor-piercing rounds, other tools and instruments, and jewelry.Tungsten carbide is approximately two times stiffer than steel, with a Young's modulus of approximately 530–700 GPa, and is much denser than steel or titanium.It is comparable with corundum (α-Al2O3) in hardness and can only be polished and finished with abrasives of superior hardness such as cubic boron nitride and diamond powder, wheels, and compounds.TitaniumTitanium can be alloyed with iron, aluminium, vanadium, and molybdenum, among other elements, to produce strong, lightweight alloys for aerospace (jet engines, missiles, and spacecraft), military, industrial process (chemicals and petro-chemicals, desalination plants, pulp, and paper), automotive, agri-food, medical prostheses, orthopedic implants, dental and endodontic instruments and files, dental implants, sporting goods, jewelry, mobile phones, and other applications.The two most useful properties of the metal are corrosion resistance and the highest strength-to-density ratio of any metallic element. In its unalloyed condition, titanium is as strong as some steels, but less dense.There are two allotropic forms and five naturally occurring isotopes of this element, 46Ti through 50Ti, with 48Ti being the most abundant (73.8%). Although they have the same number of valence electrons and are in the same group in the periodic table, titanium and zirconium differ in many chemical and physical properties.​Super Metals of the Marvel Universe (Earth-616)Marvel's canon Earth-616 is rife with imaginary metals and metallic alloys. Most of these have nothing to do with real science and everything to do with comic hyperbole.The short list includes:Proto-Adamantium: The adamantium-vibranium found uniquely within Captain America's shield (now with added Uru!) A device so unusually durable, it has only been broken a handful of times in its entire existence.In any case where it shouldn't have been broken, it was later retconned and a facsimile was being broken instead. It has only failed against magical beings who were wielding the Odin-force, an all-powerful magic, and the source of the Asgard's mystical might. The shield also failed against the Thanos when he was using the Infinity Gems.The shield's greatest strength is its nearly immutable nature and resistance to being damaged or changed. The process used to create adamantium requires the material be brought together, shaped and within a fixed amount of time before setting.The process used to create Captain America's shield was similar to the normal process of adamantium development with the inclusion of vibranium. The process was lost and therefore unable to be repeated.I accept this is the origin of Captain America's shield BUT:Thanks to a sleepy scientist and a time traveler from the future...I mean what we are to expect, some vibranium found its way into the secured locked lab when it wasn't there before?And with the mysterious addition of vibranium, we create a device which has been at the center of dozens of temporal events which changed the future.Nobody, Tony Stark, Reed Richards, or Doctor Doom have tried to figure out why they can't recreate Captain America's shield because...what? It would give Stark or Doom the perfect impenetrable armor, resistant to everything in the universe?Why wouldn't Reed Richards want to sit around for a few weekends with Cap's shield and learn how it was made so he could make everything he wants to keep COMPLETELY INVULNERABLE? Isn't that worth a weekend or two, Reed?When you can't get Proto-Adamantium (and you can't, I tried), you end up with the next most amazing thing: Adamantium.Adamantium is incredibly hard to come by, can be used to coat normal metals to enhance their durability as well. Almost impossible to make on Earth-616, process is limited to a select few corporations. Most notably found in Ultron's nigh-indestructible carapace. It can also be found coating Doctor Octopus' tentacles increasing their durability and strength.​Yes, this android which is beating both Thor and Wonder Man like ugly step-children. Ultron is coated in Adamantium making his super-strength even more formidable, because he can put his back into every swing. No stress fractures on him...no strings either.Secondary Adamantium: When you can't afford real adamantium, you make, buy or steal this. Nearly as good, far more durable than normal metallic alloys, very, very expensive.Adamantium Beta: Wolverine's Skeleton and claws are made from this. Unique to Wolverine or any mutant fitted with secondary adamantium which is somehow altered by their regenerative properties (There's at least a couple - Lady Deathstrike, Sabertooth - see, I named two.) Don't think any more about it. Impenetrable metal worn down by regeneration powers... Here you go ladies, a picture of Hugh Jackman as Wolverine.​Vibranium A: A metallic substance which absorbs vibrational energy, once found exclusively in the African kingdom of Wakanda. It was of extraterrestrial origins. The Wakandan stockpile was recently destroyed before Marvel's soft reboot in Secret Wars 2015.While not as durable as Adamantium, it is a very resilient alloy and can be very durable particularly when it comes to absorbing incoming kinetic energy attacks. Vibranium A makes for great body armor and can allow a properly fitted wearer to fall great distances without injury. Black Panther once wore a uniform fitted with a variety of vibranium technologies for his protection.​Vibranium B: Also known as anti-metal, which destroys metallic bonds even in adamantium. Black Panther used to have claws made from it. This material was found exclusively in the Savage Land.Uh. I forgot to mention the Savage Land has dinosaurs. And mutants. And Humans running around with saber-toothed beasts. Some guy name Ka-Zar...​In the Marvel Cinematic Universe​Captain America's shield in the Marvel Cinematic Universe (Earth-199999) is NOT indestructible; far from it.Created by Howard Stark from a vibranium alloy, the MCU shield is very tough but nowhere near as durable as Captain America's shield in the comics. With sufficient force or continued bombardment, a shield composed of only vibranium can be destroyed as the vibranium destabilizes.VibraniumVibranium is not as hard or dense as Adamantium, but it is still very durable. The apparent observable vibratory rate of the molecules of the Vibranium itself does not noticeably increase when the Vibranium absorbs mechanical energy.The outside vibratory energy is stored within the bonds between the molecules making up the Vibranium. As a result, a chunk of Vibranium which had absorbed a considerable amount of vibratory energy would be exceedingly hard to demolish.If enough force were were applied to this chunk to smash it, the Vibranium would explode, releasing much of the absorbed energy in a fashion similar to a large multi-megaton bomb.​Captain America's MCU shield is composed singularly from a vibranium-metallic alloy. Durable, tough, damage resistant, capable of taking a hit from even Mjolnir, but far weaker than the comic version of Cap's shield.​Runner-Ups after Adamantium for durability​Carbonadium: Carbonadium is a resilient, unstable metal that is vastly stronger than steel; think of it as a synthetic and poor man's adamantium, very durable but also radioactively toxic as well. Must have a healing factor to use this metal. Most commonly associated with Omega Red. (above)​​You might want to duck. Mjolnir coming through!Enchanted uru is not made or normally found on Earth and is both more resistant to damage than normal uru metal but it is not indestructible.It's durable and can be enchanted to be even more damage-resistant but its primary benefit is the ability to bind amazing enchantments to it. Thor's hammer, Mjolnir, is made of from it; hard to come by, even in Asgard, dwarves horde it.​The titanic tussle between two titans who terrorize timid tenants: Hercules, Prince of Power versus the Mighty Thor.Adamantine: To be fair to Marvel's Olympians, I will also include Adamantine, the material Hercules' Golden mace is was forged from. In the Marvel Universe, adamantine is a mystical metal capable of being enchanted and having its durability enhanced through mystical/scientific forging by Hephaestus, the smith of the Olympian gods.​Iron Man Armors: - composed of metallic and ceramic-enhanced alloys allowing for durability, these armors can have their strength and durability further enhanced by charging it with electrical energies and integrated force fields.Osmium: A real metal, it makes this list because Colossus, the Living Juggernaut's mutant power is to transform into a being composed of an organic or living form of this dense and resilient metal.​Cosmically-Enhanced Materials in the Marvel Universe​​In the current iterations of the Marvel Universe, the nature of the most powerful materials would be similar to the nature of the technological capabilities of the species; more advanced species would likely have better metallurgical technologies.In addition to better metallurgy these species may be able to infuse materials with energy, reinforcing the material's strength, resilience and durability.Adding to this mixture, concepts such as nanotechnology, memory materials, programmable matter and other meta-material science means such species have an unknowable advantage over species without such advancements.Their armors may be self-repairing, adaptable to varying environmental conditions on their own and maybe even self-aware, able to compensate against threats without direction from its wearer.Beings who have mastered all of the universes fundamental forces, matter and energy manipulation making them with the proper scientific knowledge to create the penultimate meta-materials. These entities include the Elders of the Universe, the Stranger and the the armor of the Space gods, the Celestials.Galactus, Scourge of Worlds, was ancient when the Universe was new. He forged his current armor from materials in this universe and except for in the presence of matter manipulation entities whose powers rival his own, his armor is impenetrable.Since Galactus imbues his heralds with a segment of the Power Cosmic, they too have some ability to create nearly indestructible materials either as armor or weapons unable to be affected by beings with lesser technologies. This includes the Silver Surfer's surfboard and the ax and armor of Terrax the Tamer.​Galactus created the Silver Surfer, so it's safe to say the Silver Surfer is highly resistant to damage, considering his job duties and the potential threats he faces, he needs to be. Skirting black holes, wormholes, and stars, the Surfer's metallic skin is one of the toughest surfaces imaginable.Since Galactus and the Surfer both possess matter transmutation and advanced scientific capacity they can create or alter matter to make the strongest materials in the Universe. Other cosmic beings can likely create similar near-ultimate materials.This may also include unique weapons of the local god-like beings associated with Earth, such as Odin's spear, Gungnir.In the Marvel Universe, just because a particular metal ranks well, does not mean it cannot be damaged. With sufficient force, magic, technology or knowledge, almost anything can trump anything else, hence the reason Thor and the Hulk manage to damage anyone and everyone on this list at least some of the time.Ringworld​Ringworld is a 1970 science fiction novel by Larry Niven, set in his Known Space universe and considered a classic of science fiction literature. Niven later added four sequels and four prequels. These books tie into numerous other books set in Known Space. Ringworld won the Nebula Award in 1970, as well as both the Hugo Award and Locus Award in 1971.General Products Hull:In Larry Niven's fictional Known Space universe, General Products is a Pierson's Puppeteers company which produces various spacecraft components.The most famous (and most profitable) items produced by General Products are General Products hulls, which are advertised as being impervious to anything apart from visible light (as defined by wavelengths visible to any of the species which are customers of General Products), antimatter, and gravity.The hulls are advertised as being capable of passing through the upper atmosphere of a star without damage, although the contents may become overcooked (but see below for a solution to this problem).The company even offers a guarantee that, should anything harm you within a General Products hull as a result of a failure of these specifications, you (or your estate) will receive a very large sum of money ("tens of millions" of "stars" in the event of a death, with a "star" having value roughly equivalent to one United States dollar in the middle of the 20th century).In the history of General Products this indemnity has been claimed only once, by Gregory Pelton, whose hull failed under extremely unusual circumstances (see Flatlander).Scrith:Scrith is the milky-gray translucent, nearly frictionless material that forms the walls and floor of the Ringworld in Larry Niven’s Ringworld.It is said that Scrith was artificially produced by transmutation of matter, and is nearly impervious to most weapons. Scrith absorbs heat and radiation nearly perfectly and can block neutrinos as well as a light year worth of lead.Some amateur scientists postulated Scrith couldn't technically exist since the mathematics to create Ringworld would require Scrith to be stronger than the strong nuclear force! Impossible.This means the Ringworld cannot exist outside of an appropriately-belief suspended environment.Lord of the Rings​Mithril: was a precious Silvery metal, very lightweight but capable of providing extreme strength in alloys, which was mined by the Dwarves in the deep mines of Khazad-dûm. This was considered a rare gift and extremely strong metal. Highly prized it was rarely seen in hands outside of dwarves.Galvorn: was the shining black metal devised by master craftsman Eöl. It was harder than mithril and nearly impossible to smith by anyone but a master-craftsman. The technique was believed lost when Eöl died.Tilkal: was a unique metal created by the Vala Aulë in the earlier forms of the legendarium.The metal was composed of six different metals that made it extremely strong, hard, bright, and smooth. The light that shown on it and what it was exposed to caused it to vary in color. Only Aulë knew the secret of its manufacture. It was used to bind Melkor for his tsignNowery in the Silmarillion.The Culture (Iain Banks - Consider Phlebas)​An artist's representation of the very durable, nearly-living starships of Iain Bank's Culture GSV.​General Systems VehicleEach Systems Vehicle was a great space-faring city that represented everything the Culture was socially, technologically, etc.. They built smaller ships, such as General Contact Units, and manned them from their own populations.A General Systems Vehicle (GSV) was the largest and most capable type of Systems Vehicle, and served as the Culture's premier ambassadors. The Culture's capabilities were almost totally mirrored on a smaller scale in a GSV.These titanic vessels house vast populations, factories or defense forces -- each controlled by a trio of extremely powerful artificial intelligences called Minds.These number crunchers do all the heavy lifting while the humanoids in their charge are free to peruse whatever sort of hedonistic or altruistic lifestyle they desire.​Star Wars Materials​With the lightsaber as the gold standard for damage-dealing in the Star Wars universe, you might be surprised to discover there were numerous metals, compounds and even genetically engineered creatures who could resist a lightsaber's gentle touch.All of these metals, compounds or alloys are resistant to the plasma temperatures of a light-saber, which makes them pretty durable. Most were very rare or expensive and thus found themselves in the hands of soldiers, bounty hunters, warriors and occasionally Jedi and Sith.Lightsaber-resistant materials (Wookiepedia - Star Wars Wiki)Amphistaff: Genetically engineered serpentine creatures that served as the primary anti-personnel weapons of the Yuuzhan Vong.Amphistaffs were one of the most durable objects known, as not even lightsabers could cut through them. When used as a heavy staff, the serpent would endure blow after blow from the Jedi weaponry and remain unfazed.The amphistaff's edge—measured in atoms—slashed through flesh with no resistance. In the blink of an eye, the amphistaff could soften and wind around the lightsaber's blade, its venomous jaws snapping and tearing at the unfortunate victim's face.Because of its organic nature, these creatures were capable of recovering from virtually any wounds. Nigh indestructible, an amphistaff could only be killed by repeated blunt trauma to or removal of the head.Cortosis ore: A very rare, brittle, fibrous material whose conductive properties caused lightsabers to temporarily short out upon contact. This effect made cortosis a useful material for anti-lightsaber melee weapons, though with repeated strikes, a lightsaber could still cut through it. Cortosis, due to its energy resistant properties, was also resistant to blaster fire.Felucian Skullblade: Felucian Skullblades were constructed from the skull and teeth of specific native creatures. These creatures grew trace amounts of Force-reactive crystals, similar to those used in the construction of lightsabers, in their bones allowing weapons constructed from them, when imbued with the Force, to block lightsabers and blaster fire.Mandalorian iron: also known by its Mando'a name of beskar, was a near-indestructible iron ore whose only known source was the Outer Rim world of Mandalore and its moon, Concordia. The Mandalorian warrior culture that inhabited Mandalore mined their planet for beskar, using it in the creation of weapons, armor, and starships, occasionally even selling the rare and valuable metal on the galactic market. A versatile metal, Mandalorian iron could be melded into multiple alloys and forged into various configurations.​Mandalorian warriors in trademark armors prepare for their next battle.Neuranium: was a metallic substance used to shield from radiation, and one of the heaviest and densest metals in the galaxy. A millimeter of it could stop most scanners, and it could even temporarily block lightsaber energy. However in order to cover a space as large as a cargo hold, it would be prohibitively heavy and thus inefficient to use.Phrik: was a rare metallic compound that was one of only a few lightsaber-resistant substances known. It was used in the construction of extremely light and durable battle armor as well as melee weapons. On a more extreme scale, at one point in the Galactic Civil War, a container of phrik was able to stay intact when it was on the surface of Alderaan during its destruction. Very rare, very expensive.Songsteel: was an extraordinarily light and luminescent silver metal, used in masterwork swords and staves. The metal was reserved only for the most exquisite of weapons, and was extremely tedious to forge and shape. Songsteel was highly resistant to lightsaber strikes in a manner similar to phrik and cortosis.Ultrachrome: was a metal used as starship armor around the time of the Great Sith War. Silver and superconductive, it reflected blaster and slugthrower weaponry, was heavily resistant to lightsaber attacks, and was immune to metal-eating fungi.Vonduun crab: The vonduun crab was an organism used to shape the vonduun crab armor suits of the Yuuzhan Vong.This list is nowhere near complete..."Pardon the crudity of the model, I didn't have time to paint it or cut it to scale."If you can think of a metal, well-known or interesting artifact or nigh-indestructible technology that should be on this list, write it in the comments with some information on how to find it, what books it came from and if I know anything about it, I will add it to the list. Thanks for reading.

Warning long answer!Since 1990, I’ve been studying the confidentiality of the messaging systems on computers and mobile devices.It was obvious that the electronic forums, emails and SMS messages could easily be intercepted by 3rd parties. Expecting the service providing companies to develop and implement confidentiality protocols were unrealistic. There were never a general consensus about the need for confidentiality or inter-service protocol development.With the discouragement of the governments many computer scientists shied away from creating software to keep communication confidential between parties.Many spy movies showed advanced technologies to keep the communication between spies and their organizations. The most famous being the Enigma machine used by the Germans during the World War 2. British scientist Alan Turing was the one to develop an early version of today’s computers to solve the mystery of the Enigma machine. Like every visionary he had serious problems with the establishment. After the government discovering that he was gay, he was given 2 options. First option was jail time until he turned heterosexual, or chemical castration. Poor Turing chose the second option and after a while he committed suicide. Every cryptologist today remembers to what happened to the first representative of this science.Without getting into the technological terms (they are all available on Wikipedia) the best way to keep conversation confidential is to use a code book between 2 (or more, but more on that later) parties. A code book is a simple definition and a list of codes that is shared between the parties and each code is used only once. Unless the code book is compromised this method of communication privacy is bullet proof. There is no computer in the world, and there won’t be any in the future that can figure out what the communication is. The only method would be the old school spying on the parties who are communicating between each other.If I need to give an example for the method above, it would be like, let’s choose a newspaper that is accessible to both parties. That will be our message base.Let’s define a codebook now:First code in the book is3–4,6–7,1–2 and repeats itselfsecond code is5–7,3–1,8–5,4–2 and repeats itselfSo let’s say I send you a message today like20,42,15,5,8,67,23,56,12,43,13,11,10Since it is our first message exchange you will use the first code in the book. Also our message base is only known to us which also makes it even more difficult for others to understand the secret message I just sent you.To understand the message, here is what you do: you pick up today’s New York Times which is the newspaper we agreed to use.Take the first number in the secret message which is 20, then look in the codebook for the first code which is 3–4. You go to the 3rd page find the 4th paragraph and get the 20th character and repeat this process for each number in the secret message I sent.Let’s say MI6 is trying to intercept the message, which they do because I sent the message by email or SMS or event with both to you.All they have is 20,42,15,5,8,67,23,56,12,43,13,11,10 and they have no idea what it means. They don’t know which text source we used, which was New York Times and they don’t know the code we used for that message which was 3–4,6–7,1–2. We can even make this more difficult, for each day of the week we use a different newspaper that we agree upon.And let’s say MI6 figures out which newspaper we use for each day, let’s say they even figure out our code mechanism which is the page, paragraph and character to decode the secret message.As long as we use each line of code only once and never repeat used codes, there is virtually no way that MI6 to figure out our conversation. Except of course sending their double o agent to one of us and beating us in the head with an iron bar which would make us sing like a bird and spill all the secrets.As you can see in the example an iron bar, strategically placed on your head with a moderate blow would break all the code we established.That reality aside, if I whisper to your ear the newspaper names and hand you a piece of paper with a list of codes which I also have the same copy, until ve run out of codes there is no way our communication can be interpreted when intercepted.The difficulty in this type of message confidentiality is sharing and keeping a piece of paper with a list of codes and do the code exchange again when the list of codes are depleted and never use a code again.When this is not possible for practical reasons like distance between parties or the number of messages exchanged being too high and frequent the methodology used is computer based encryption (ensuring the confidentiality of communication between parties) of messages.This is also not so unlike what we did in the first example. To create our never ending codes is that for each message we exchange we use 3 constants. You have a master key, a public key and we agree on a mathematical formula which is very very difficult for the computer to solve. The difficulty here ensures that the time to try every combination of variables (without the master key) for the formula is so long, it practically makes it impossible for others to guess our code list.In this method I also have a master key and a public key. To solve the issue of keeping a list of established codes and communicating that between parties we freely exchange our public keys with everyone and when I’m sending you a message, I use your public key (any of my keys except generating a special signature with my private key so that you can validate with my public key that ensures the message has originated really from me) to create a confidential message. When you receive it by email, SMS or regular post mail, you use your private key which can only find out the contents of the confidential message. And since we are talking about computer systems, we protect our private keys with passwords.I don’t like using names given by computer engineers or any other technical person but for the sake of clarification this master/public key and an established algorithm to use is called public private key cryptology.Another term I don’t like is ‘end to end encryption’. This is to confirm that the cryptology method used can not be intercepted by other parties and only the recipient can understand the contents of the message.One company who has developed an implementation of end to end encryption is Open Whisper Systems. They named their product ‘Signal’ which is a platform and also the name of their app on iOS and Android. Their product uses this public private key cryptology to ensure the text and voice communications between parties to stay confidential. Supposedly the infamous NSA whistle blower Edward Snowden uses their app and he considers it quite good.Now let’s circle back to the WhatsApp security issue. WhatsApp is using the protocol established by the Open Whisper Systems for their public private key protected communications (audio, video and text messages).The problem is the user friendliness of the Signal app is not good. There are certain times that these public and private keys have to be changed. 2 example of those times is if you change your phone or uninstall / reinstall your app (whichever app you are using, Signal or WhatsApp)To test the user friendliness of Signal App’s handling the change of the key pairs (public private key combinations) I used my regular human guinea pig Riz. It was very difficult for me to explain what he has to do and also to find the location of the menu items were horribly difficult. After cursing at me and the app designers many times Riz completed the approval of the new key exchange between us so we could communicate again.Let’s have a look into how WhatsApp has implemented this renewal of key pairs between users. Since authenticity of a user can only identified by trusting their private key signed signature and for the likely case of the user have a new phone or has reinstalled the WhatsApp App, WhatsApp servers keep a copy of the secret message until the recipient downloads it. Now let’s say that you sent me a message while I was offline and I changed phones meanwhile. When I get that message from you what the Signal app does is, it warns me and it won’t let you communicate with you until I approve your new public key (in the style of a combined public keys of both parties because there is only one code that needs to be verified on both ends). Instead of asking user to do the verification what WhatsApp does it re-encrypts your message with my new key again (in their explanation by asking your WhatsApp to keep that message in memory in encrypted form and first decrypt then re-encrypt the same message with my new public key) without asking neither of us to re-confirm the identity of both parties.This technically opens up a backdoor for intelligence agencies to decrypt the messages between parties.How does that happen? WhatsApp confirms App installation by SMS confirmation. Let’s say I want to intercept your WhatsApp messages. I send a team in a delivery van which looks like a repair van but which has a mobile communication signal jammer to your home address. The jamming is smart enough to make your phone think it is still in network coverage so you don’t suspect a thing unless you try to make a call which will look like mobile network is crowded and unavailable. While I knock your phone off the network I can do 2 things, I can either intercept any SMS messages which comes your way in my service van, or give a court order to the mobile phone company to give me a copy of your SMS messages in real time.Then I install WhatsApp on a new phone, enter your phone number as my number and receive a copy of the SMS confirmation with the verification number and enter it in WhatsApp. From that moment on I will receive any waiting (since I knocked you off mobile network) and any news messages WhatsApp users send to you.Intentional or unintentional this is a secret door that can be easily used by government agencies.If I used the above technique to intercept messages between Signal users, what would happen were to be, first I couldn’t receive any messages waiting in the cloud because Signal does not keep messages in the cloud, when you are offline, the message waits in the sender’s Signal App. When the sender tries to send a new or resend the unsent message to you, my new installation of Signal app on my government agency phone will inform your friend, the sender that I’ve changed our shared agreed secret code and asks your friend if s/he wants to approve this new installation on the other end by confirming the new shared secret code with you. When s/he calls you on your landline, you say you haven’t installed a new WhatsApp on your phone or changed phones, you both understand that there is another party in between trying to intercept your messages.Now, WhatsApp says that there is an option in their App, under Settings / Account / Security / Show Security Notifications which is by default off. If you turn this ON then their claim is you will receive notifications when a contact’s security code has changed. They don’t say if the messages will still be delivered in spite of a security notification or not. They add that ‘The messages you send your calls are encrypted regardless of this setting, WHEN POSSIBLE’. I capitalized the last 2 words, what the heck ‘WHEN POSSIBLE’ mean? They also do not say anything about the messages you are going to receive. Even though you enable this warning setting on, if your friend’s setting is not on, they will not be notified if the messages they are sending to you are intercepted.This unintentional secret door is called a ‘user friendly design choice’ by WhatsApp. It is such a user friendly design choice it is government agents friendly as well. I can’t imagine how many diplomats already delivered confidential messages to enemy agencies using WhatsApp. Diplomats in Brussels wake up and smell the coffee…

Some of the frequently asked Interview questions for java developers are:1   What is an object ? 2   What is method overriding in java ? 3   What is super keyword in java ? 4   What is method overloading in java ? 5   What is difference between c++ and Java ? 6 What is JIT compiler ? 7   What is bytecode in java ? 8   Difference between method overloading and method overriding in java ? 9   Difference between abstract class and interface ? 10   Why java is platform independent? 11 Difference between this( and super( in java ?12 How to call one constructor from the other constructor ? 13 what are static blocks and static initalizers in Java ? 14 What is method in java ? 15 What is constructor in java ? 17 Difference between Character Constant and String Constant in java ?18 Why main( method is public, static and void in java ? 19 Explain about main( method in java ? 20 What is difference between length and length( method in java ? 21   What  is ASCII Code? 22 What is Unicode ? 23 What are constants and how to create constants in java? OOPS24 Explain about object oriented programming and its features? 25 What is Abstraction? 26 What is Encapsulation? 27 What is the difference between abstraction and encapsulation? 28 List out benefits of object oriented programming language? 29 Differences between traditional programming language and object oriented programming language? 30 What is Inheritance? 31 What is Polymorphism? 32 How does Java implement polymorphism? 33 Explain the different forms of Polymorphism 34 What is runtime polymorphism or dynamic method dispatch? 35 What is Dynamic Binding? 36 What is method overloading? 37 What is method overriding? 38 What are the differences between method overloading and method overriding? 39 Can overloaded methods be override too? 40 Is it possible to override the main method? 41 How to invoke a superclass version of an Overridden method? 42 What is super? 43 How do you prevent a method from being overridden? 44 What is an Interface? 45 Can we instantiate an interface? 46 Can we create an object for an interface? 47 Do interfaces have member variables? 48 What modifiers are allowed for methods in an Interface? 49 What is a marker interface? 50 What is an abstract class? 51 Can we instantiate an abstract class? 52 What are the differences between Interface and Abstract class? 53 When should I use abstract classes and when should I use interfaces? 54 When you declare a method as abstract, can other nonabstract methods access it? 55 Can there be an abstract class with no abstract methods in it? 56 What is IS-A relationship  in java?57 What is HAS A relationship in java?58 Difference between IS-A and HAS-A relationship in java?59 Explain about instanceof operator in java?60   What does null mean in java?61   Can we have multiple classes in single file ?62   What all access modifiers are allowed for top class ?63 What are packages in java?64   Can we have more than one package statement in source file ?65   Can we define package statement after import statement in java?66 What are identifiers in  java?67 What are access modifiers in java?68   What is the difference between access specifiers and access modifiers in java?69   What access modifiers can be used for class ?70   Explain what access modifiers can be used for methods?71   Explain what access modifiers can be used for variables?72   What is final access modifier in java?73   Explain about abstract classes in java?74 Can we create constructor in abstract class ?75   What are abstract methods in java?Type Casting      76 What is TypeConversion? 77 Explain Implicit Conversion/ Widening/Automatic Type Conversion? 78 What is Explicit Conversion/Narrowing/Casting? 79 Can a double value be cast to byte? How to cast double value to byte with help of the example? 80 Can a Boolean primitive value to be converted to any other primitive in java? 81 What is autoboxing and autounboxing? 82 What are advantages of autoboxing and autounboxing? 83 How to cast objects or what is object casting? 84 What is upcasting or downcasting? Exception Handling85   State some situations where exceptions may arise in java?86   What is Exception handling in java?87    What is an eror in Java?88   What are advantages of Exception handling in java?89   In how many ways we can do exception handling in java?90   List out five keywords related to Exception handling ?91   Explain try and catch keywords in java?92   Can we have try block without catch block?93    Can we have multiple catch block for a try block?94   Explain importance of finally block in java?95   Can we have any code between try and catch blocks?96   Can we have any code between try and finally blocks?97   Can we catch more than one exception in single catch block?98   What are checked Exceptions?99   What are unchecked exceptions in java?100   Explain differences between checked and Unchecked exceptions in java?101 What is default Exception handling in java?102   Explain throw keyword in java?103   Can we write any code after throw statement?104 Explain importance of throws keyword in java?105 Explain the importance of finally over return statement?106 Explain a situation where finally block will not be executed?107   Can we use catch statement for checked exceptions?108   What are user defined exceptions?109   Can we rethrow the same exception from  catch handler?110   Can we nested try statements in java?111 Explain the importance of throwable class and its methods?112 Explain when ClassNotFoundException will be raised ?113 Explain  when NoClassDefFoundError  will be raised ?Nested Class & Inner Class114 What are inner classes or non static nested classes in java? 115   Why to use nested classes in java? 116   Explain about static nested classes in java? 117 How to instantiate static nested classes in java? 118   Explain about method local inner classes or local inner classes in java? 119 Explain about features of local inner class? 120 Explain about anonymous inner classes in java? 121 Explain restrictions for using anonymous inner classes? 122   Is this valid in java ? can we instantiate interface in java? 123 Explain about member inner classes? 124 How to instantiate member inner class? 125 How to do encapsulation in java? 126 What are reference variables in java ? 127 Will the compiler creates a default constructor if I have a parameterized constructor in the class? 128   Can we have a method name same as class name in java? 129   Can we override constructors in java? 130 Can Static methods access instance variables in java? 131 How do we access static members in java? 132    Can we override static methods in java? 133 Difference between object and reference? 134 Objects or references which of them gets garbage collected? 135 How many times finalize method will be invoked ? who invokes finalize( method in java?136 Can we able to pass objects as an arguments in java? 137 Explain wrapper classes in java? 138 Explain different types of wrapper classes in java? 139 Explain about transient variables in java? 140 Can we serialize static variables in java? 141   What is type conversion in java? 142   Explain about Automatic type conversion in java? 143 Explain about narrowing conversion in java? 144 Explain the importance of import keyword in java? 145 Explain naming conventions for packages ? 146 What is classpath ? 147 What is jar ? 148 What is the scope or life time of instance variables ? 149 Explain the scope or life time of class variables or static variables? 150 Explain scope or life time of local variables in java? 151   Explain about static imports in java? 152 Can we define static methods inside interface? 153 Define interface in java? 154 What is the purpose of interface? 155 Explain features of interfaces in java? 156 Explain enumeration in java? 157 Explain restrictions on  using enum? 158 Explain about field hiding in java? 159   Explain about Varargs in java? 160 Explain where variables are created in memory? 161 Can we use Switch statement with Strings? 162 In java how do we copy objects? Theads163 What is thread in java? 164   Difference between process and thread? 165   What is multitasking ? 166   What are different types of multitasking? 167   What are the benefits of  multithreaded programming? 168   Explain thread in java? 169   List Java API that supports threads? 170   Explain about main thread in java? 171   In how many ways we can create threads in java? 172   Explain creating threads by implementing Runnable class? 173 Explain creating threads by extending Thread class ? 174 Which is the best approach for creating thread ? 175   Explain the importance of thread scheduler in java? 176   Explain the life cycle of thread? 177   Can we restart a dead thread in java? 178   Can one thread block the other thread? 179 Can we  restart a thread already started in java? 180 What happens if we don’t override run method ? 181   Can we overload  run( method in java? 182 What is a lock or purpose of locks in java? 183   In how many ways we can do synchronization in java? 184   What are synchronized methods ? 185 When do we use synchronized methods in java? 186   When a thread is executing synchronized methods , then is it possible to execute other synchronized methods  simultaneously by other threads? 187 When a thread is executing a synchronized method , then is it possible for the same thread to access other synchronized methods of an object ? 188 What are synchronized blocks in java? 189   When do we use synchronized blocks and advantages of using synchronized blocks? 190   What is class level lock ? 191   Can we synchronize static methods in java? 192   Can we use synchronized block for primitives? 193   What are thread priorities and importance of thread priorities in java? 194   Explain different types of thread priorities ? 195   How to change the priority of thread or how to set priority of thread? 196   If two threads have same priority which thread will be executed first ? 197 What all methods are used to prevent thread execution ? 198 Explain yield( method in thread class ? 199   Is it possible for yielded thread to get chance for its execution again ? 200 Explain the importance of join( method in thread class? 201   Explain purpose of sleep( method in java? 202   Assume a thread has lock on it, calling sleep( method on that thread will release the lock? 203 Can sleep() method causes another thread to sleep? 204 Explain about interrupt() method of thread class ? 205 Explain about interthread communication and how it takes place in java? 206 Explain wait() , notify() and notifyAll() methods of object class ? 207 Explain why wait(), notify() and notifyAll() methods are in Object class rather than in thread class? 208 Explain IllegalMonitorStateException and when it will be thrown? 209   when wait(), notify(),notifyAll() methods are called does it releases the lock or holds the acquired lock? 210   Explain which of the following methods releases the lock when yield(), join(),sleep(),wait(),notify(), notifyAll()methods are executed?211   What are thread groups? 212 What are thread local variables ? 213 What are daemon threads in java? 214 How to make a non daemon thread as daemon? 215 Can we make main() thread as daemon?Collection Framework216 What is collection ?217 Difference between collection, Collection and Collections in java?218 Explain about Collection  interface in java ?219 List  the interfaces which extends collection interface ?220 Explain List interface ?221 Explain methods specific to List interface ?222 List implementations of List Interface ?223   Explain about ArrayList ?224 Difference between Array and ArrayList ?225   What is vector?226 Difference between arraylist and vector ?227   Define  Linked List and its features with signature ?228   Define Iterator and methods in Iterator?229 In which order the Iterator iterates over collection?230   Explain ListIterator and methods in ListIterator?231 Explain about Sets ?232 Implementations of Set interface ?233   Explain HashSet and its features ?234 Explain Tree Set and its features?235 When do we use HashSet over TreeSet?236 What is Linked HashSet and its features?237 Explain about Map interface in java?238 What is linked hashmap and its features?239   What is SortedMap interface?240   What is Hashtable and explain features of Hashtable?241 Difference between HashMap and Hashtable?242 Difference between arraylist and linkedlist?243 Difference between Comparator and  Comparable in java?244 What is concurrent hashmap and its features ?245 Difference between Concurrent HashMap and Hashtable and collections.synchronizedHashMap?246 Explain copyOnWriteArrayList and when do we use copyOnWriteArrayList?247 Explain about fail fast iterators in java?248 Explain about fail safe iterators in java?Serialization249 What is serialization in java? 250 What is the main purpose of serialization in java? 251 What are alternatives to java serialization? 252 Explain about serializable interface in java? 253 How to make object serializable in java? 254 What is serial version UID and its importance in java? 255 What happens if we don’t define serial version UID ? 256 Can we serialize static variables in java? 257 When we serialize an object does the serialization mechanism saves its references too? 258 If we don’t want some of the fields not to serialize How to do that? 259 Explain importance of object class in java? 260 Explain purpose of object class or why object class is super class for all java classes? 261 Explain Object class methods? 262 List methods which can be overrided from Object class? 263 Explain purpose of toString( method in java?Strings 264 Explain Strings in java?265 Difference between Strings and Character Arrays in java?266 Explain importance of String class in java?267 In how many ways we can create Strings in java?268 Explain how to create Strings using String literal and advantages of creating Strings using String literal?Class Loaders 269 What are classloaders and different types of class loaders in java?270 What is BootStrap class loader and how does it works?271 What is Extensions class loader and how does it works?272 What is application class loader and how does it works?273 When an object becomes eligible for garbage collection?274 Who performs garbage collection?275 When does garbage collector run?276 Which algorithm garbage collector uses to perform garbage collection?277 List out different garbage collection algorithms?278 Can we force JVM for garbage collection?279 How to request jvm to perform garbage collection operation?280 Explain the purpose of finalize method in relation to Garbage collection?281 How many times finalize method is called on an Object?282 Once an object is garbage collected can it become signNowable again?283 How to write a code that makes an object eligible for garbage collection?

When it comes down to choosing a good solution to manage your documents, whether you’re an individual, or part of a company, there are a few things to consider, and it basically boils down to what you need the software to accomplish, how much automation you want, how easy do you want it to be.A good all around option I’d suggest checking out it Kdan Document 365. It has some nice features to help you manage your PDFs (editing, signing, etc.,) and other kinds of documents you might be working with. If you’re part of a company, it’s easy to share and collaborate on projects/documents/presen...

Since 1990, I’ve been studying the confidentiality of the messaging systems on computers and mobile devices.It was obvious that the electronic forums, emails and SMS messages could easily be intercepted by 3rd parties. Expecting the service providing companies to develop and implement confidentiality protocols were unrealistic. There were never a general consensus about the need for confidentiality or inter-service protocol development.With the discouragement of the governments many computer scientists shied away from creating software to keep communication confidential between parties.Many spy movies showed advanced technologies to keep the communication between spies and their organizations. The most famous being the Enigma machine used by the Germans during the World War 2. British scientist Alan Turing was the one to develop an early version of today’s computers to solve the mystery of the Enigma machine. Like every visionary he had serious problems with the establishment. After the government discovering that he was gay, he was given 2 options. First option was jail time until he turned heterosexual, or chemical castration. Poor Turing chose the second option and after a while he committed suicide. Every cryptologist today remembers to what happened to the first representative of this science.Without getting into the technological terms (they are all available on Wikipedia) the best way to keep conversation confidential is to use a code book between 2 (or more, but more on that later) parties. A code book is a simple definition and a list of codes that is shared between the parties and each code is used only once. Unless the code book is compromised this method of communication privacy is bullet proof. There is no computer in the world, and there won’t be any in the future that can figure out what the communication is. The only method would be the old school spying on the parties who are communicating between each other.If I need to give an example for the method above, it would be like, let’s choose a newspaper that is accessible to both parties. That will be our message base.Let’s define a codebook now:First code in the book is3–4,6–7,1–2 and repeats itselfsecond code is5–7,3–1,8–5,4–2 and repeats itselfSo let’s say I send you a message today like20,42,15,5,8,67,23,56,12,43,13,11,10Since it is our first message exchange you will use the first code in the book. Also our message base is only known to us which also makes it even more difficult for others to understand the secret message I just sent you.To understand the message, here is what you do: you pick up today’s New York Times which is the newspaper we agreed to use.Take the first number in the secret message which is 20, then look in the codebook for the first code which is 3–4. You go to the 3rd page find the 4th paragraph and get the 20th character and repeat this process for each number in the secret message I sent.Let’s say MI6 is trying to intercept the message, which they do because I sent the message by email or SMS or event with both to you.All they have is 20,42,15,5,8,67,23,56,12,43,13,11,10 and they have no idea what it means. They don’t know which text source we used, which was New York Times and they don’t know the code we used for that message which was 3–4,6–7,1–2. We can even make this more difficult, for each day of the week we use a different newspaper that we agree upon.And let’s say MI6 figures out which newspaper we use for each day, let’s say they even figure out our code mechanism which is the page, paragraph and character to decode the secret message.As long as we use each line of code only once and never repeat used codes, there is virtually no way that MI6 to figure out our conversation. Except of course sending their double o agent to one of us and beating us in the head with an iron bar which would make us sing like a bird and spill all the secrets.As you can see in the example an iron bar, strategically placed on your head with a moderate blow would break all the code we established.That reality aside, if I whisper to your ear the newspaper names and hand you a piece of paper with a list of codes which I also have the same copy, until ve run out of codes there is no way our communication can be interpreted when intercepted.The difficulty in this type of message confidentiality is sharing and keeping a piece of paper with a list of codes and do the code exchange again when the list of codes are depleted and never use a code again.When this is not possible for practical reasons like distance between parties or the number of messages exchanged being too high and frequent the methodology used is computer based encryption (ensuring the confidentiality of communication between parties) of messages.This is also not so unlike what we did in the first example. To create our never ending codes is that for each message we exchange we use 3 constants. You have a master key, a public key and we agree on a mathematical formula which is very very difficult for the computer to solve. The difficulty here ensures that the time to try every combination of variables (without the master key) for the formula is so long, it practically makes it impossible for others to guess our code list.In this method I also have a master key and a public key. To solve the issue of keeping a list of established codes and communicating that between parties we freely exchange our public keys with everyone and when I’m sending you a message, I use your public key (any of my keys except generating a special signature with my private key so that you can validate with my public key that ensures the message has originated really from me) to create a confidential message. When you receive it by email, SMS or regular post mail, you use your private key which can only find out the contents of the confidential message. And since we are talking about computer systems, we protect our private keys with passwords.I don’t like using names given by computer engineers or any other technical person but for the sake of clarification this master/public key and an established algorithm to use is called public private key cryptology.Another term I don’t like is ‘end to end encryption’. This is to confirm that the cryptology method used can not be intercepted by other parties and only the recipient can understand the contents of the message.One company who has developed an implementation of end to end encryption is Open Whisper Systems. They named their product ‘Signal’ which is a platform and also the name of their app on iOS and Android. Their product uses this public private key cryptology to ensure the text and voice communications between parties to stay confidential. Supposedly the infamous NSA whistle blower Edward Snowden uses their app and he considers it quite good.Now let’s circle back to the WhatsApp security issue. WhatsApp is using the protocol established by the Open Whisper Systems for their public private key protected communications (audio, video and text messages).The problem is the user friendliness of the Signal app is not good. There are certain times that these public and private keys have to be changed. 2 example of those times is if you change your phone or uninstall / reinstall your app (whichever app you are using, Signal or WhatsApp)To test the user friendliness of Signal App’s handling the change of the key pairs (public private key combinations) I used my regular human guinea pig Riz. It was very difficult for me to explain what he has to do and also to find the location of the menu items were horribly difficult. After cursing at me and the app designers many times Riz completed the approval of the new key exchange between us so we could communicate again.Let’s have a look into how WhatsApp has implemented this renewal of key pairs between users. Since authenticity of a user can only identified by trusting their private key signed signature and for the likely case of the user have a new phone or has reinstalled the WhatsApp App, WhatsApp servers keep a copy of the secret message until the recipient downloads it. Now let’s say that you sent me a message while I was offline and I changed phones meanwhile. When I get that message from you what the Signal app does is, it warns me and it won’t let you communicate with you until I approve your new public key (in the style of a combined public keys of both parties because there is only one code that needs to be verified on both ends). Instead of asking user to do the verification what WhatsApp does it re-encrypts your message with my new key again (in their explanation by asking your WhatsApp to keep that message in memory in encrypted form and first decrypt then re-encrypt the same message with my new public key) without asking neither of us to re-confirm the identity of both parties.This technically opens up a backdoor for intelligence agencies to decrypt the messages between parties.How does that happen? WhatsApp confirms App installation by SMS confirmation. Let’s say I want to intercept your WhatsApp messages. I send a team in a delivery van which looks like a repair van but which has a mobile communication signal jammer to your home address. The jamming is smart enough to make your phone think it is still in network coverage so you don’t suspect a thing unless you try to make a call which will look like mobile network is crowded and unavailable. While I knock your phone off the network I can do 2 things, I can either intercept any SMS messages which comes your way in my service van, or give a court order to the mobile phone company to give me a copy of your SMS messages in real time.Then I install WhatsApp on a new phone, enter your phone number as my number and receive a copy of the SMS confirmation with the verification number and enter it in WhatsApp. From that moment on I will receive any waiting (since I knocked you off mobile network) and any news messages WhatsApp users send to you.Intentional or unintentional this is a secret door that can be easily used by government agencies.If I used the above technique to intercept messages between Signal users, what would happen were to be, first I couldn’t receive any messages waiting in the cloud because Signal does not keep messages in the cloud, when you are offline, the message waits in the sender’s Signal App. When the sender tries to send a new or resend the unsent message to you, my new installation of Signal app on my government agency phone will inform your friend, the sender that I’ve changed our shared agreed secret code and asks your friend if s/he wants to approve this new installation on the other end by confirming the new shared secret code with you. When s/he calls you on your landline, you say you haven’t installed a new WhatsApp on your phone or changed phones, you both understand that there is another party in between trying to intercept your messages.Now, WhatsApp says that there is an option in their App, under Settings / Account / Security / Show Security Notifications which is by default off. If you turn this ON then their claim is you will receive notifications when a contact’s security code has changed. They don’t say if the messages will still be delivered in spite of a security notification or not. They add that ‘The messages you send your calls are encrypted regardless of this setting, WHEN POSSIBLE’. I capitalized the last 2 words, what the heck ‘WHEN POSSIBLE’ mean? They also do not say anything about the messages you are going to receive. Even though you enable this warning setting on, if your friend’s setting is not on, they will not be notified if the messages they are sending to you are intercepted.This unintentional secret door is called a ‘user friendly design choice’ by WhatsApp. It is such a user friendly design choice it is government agents friendly as well. I can’t imagine how many diplomats already delivered confidential messages to enemy agencies using WhatsApp. Diplomats in Brussels wake up and smell the coffee…