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What Is a Blockchain ?
A blockchain can be thought of as a decentralized, immutable data structure that undergoes state transitions that modify its state. State iterates with transactions or operations on the blockchain, the small print of which are written to the block— chain. These transactions are grouped into blocks, which are linked together, making up the blockchain.Much like the event log used in event sourcing, current state is derived by replaying the state transitions that have taken place previously. A blockchain is a distributed ledger technology (DLT), a term that has emerged for describing technologies like blockchain that provide decentralized storage of data.
Development of Blockchain:
A very brief history of Blockchain technology started with the cryptocurrency Bitcoin. Bitcoin emerged in 2008, and although it had been not the first proposed cryptocurrency, it had been the primary that was completely decentralized, requiring neither a central authority for issuance nor transaction verification. Bitcoin maintains a distributed ledger containing details of all Bitcoin transactions. All Bitcoin ownership springs from these ledger entries, known as the Bitcoin blockchain. Transactions on the block- chain are generated using a simple scripting language. Fast-forward five years later to 2013, when a 19-year-old named VitalikButerin started developing a new decentralized platform supported ideas from Bitcoin that provided a more-robust scripting language for the development of applications. That platform, named Ethereum, provided a full Turing-complete language. It was first proposed in early 2014, and it launched in July 2015. Since then, several other blockchain technologies from different groups have emerged; however, Ethereum is the most mature (if you can call it that) by far, and it is the basis of this article. The Ethereum blockchain is driven by the established cryptocurrency Ether. Ether is the second-largest cryptocurrency after Bitcoin with a market capitalisation of approximately USSI billion dollars, versus Bitcoin’s USSIO billion capitalization. Ethereum is meant to serve the rear end of a secure, decentralized internet, where communication is with peers, and you not need to interact directly with single entities or organizations.
Ethereum is a global, open-source platform for decentralized applications. On Ethereum, you can write code that controls digital value, runs exactly as programmed, and is accessible anywhere in the world.
Blockchain with Java:
What’s all the fuss about this technology, and how can you work with it from your Java applications? Solution is to integrate the Ethereum blockchain into Java apps using web3j. web3j is a lightweight Java library for working with Ethereum. web3j is a highly modular, reactive, type safe Java and Android library for working with Smart Contracts and integrating with clients (nodes) on the Ethereum network.This allows you to work with the Ethereum blockchain, without the additional overhead of having to write your own integration code for the platform. For more information on web3j, you can visit https://docs.web3j.io/