Alright folks, we all have heard about Bitcoin, Ethereum, or other cryptocurrencies with funky names rolling around our news feeds, but do we as Java developers know how to easily interact with these blockchain technologies? Here are the top three Java projects that can be used to take advantage of the blockchain trend right now. The list is ordered based on GitHub repository stars. Comments and opinions are very appreciated.

BitcoinJ

The name is very descriptive, don't you think? If you have wondered how to create a bitcoin wallet and manage transactions between nodes, then you should give BitcoinJ a try. The project has a growing community and very good documentation, which makes it extremely lucrative for every developer. Of course, as most open source projects that try to gain popularity, it has limitations at the beginning. There are several known security issues aligned with open bugs and scalability problems. Still, it is extremely helpful if you want to understand how the bitcoin protocol operates. Personal opinion: Not suitable for production applications.

Web3j

One word – Ethereum. It's the second most talked-about cryptocurrency based on this cutting-edge technology. The Web3j project allows you to work with the Ethereum blockchain without the additional overhead of having to write your own integration code for the platform. Again, core features are creating a wallet, managing transactions, and this time, smart contract wrappers. Yes, you heard me – wrappers. Part of the Ethereum project is a special language called Solidity, which is a de-facto standard for creating smart contracts. Web3j's smart contract wrappers are used if you want to avoid the underlying implementation details for working with smart contracts. If this is not enough for you as a developer, I need to tell you that Web3j is reactive. Good documentation along with plenty of examples makes web3j my personal favorite.

HyperLedger Fabric

HyperLedger Fabric is where enterprise meets blockchain. The Linux Foundation's framework intended as a backbone for developing blockchain solutions. This, my friends, should be considered a powerful tool no matter whether you want to create a simple PoC or a production application. The project is actively under development from the Linux Foundation members. Its main focus is on creating and managing smart contracts. Key features are:

• Managing channels for sharing confidential information

• Endorsement policies for transactions

• Consistent delivery of transactions to peers in the network

If you include HyperLedger Fabric in your software blockchain stack, then my advice is to get familiar with the other HyperLedger projects. Depending on your needs, you can select various HyperLedger projects that will guarantee a coherent, scalable, and easy-to-maintain blockchain infrastructure. For many people, blockchain will transform the whole Internet. Don't you want to be part of this phenomenon?

Share, comment, and extend this list with other Java blockchain projects!