The Bitcoin ecosystem and landscape suffers from limited inter-operability. Nicolas Dorier did some great work with NBitcoin:
https://github.com/MetacoSA/NBitcoin NBitcoin offers a lot of features bitcoind and bitcoinJ do not:
- TransactionBuilder to create transactions easily
- Transacting indexing
- Cloud/Azure integration
- OpenAssets
- most BIPs: BIP32, BIP38, ...
I think these kinds of things should be available to the Bitcoin ecosystem as a whole. Is anyone interested in helping building part or all of these functions in Java (and/or C/Python)?