Simple block chains service layer implementation.

BlockChainService.java

@Service
public class BlockChainService {

    private BlockChain blockChain = new BlockChain();

    public BlockChainService() {
        blockChain.addBlock(new Block(0, "", new ArrayList<>(), 0));
    }

    public void addTransaction(Transaction transaction) {
        blockChain.addTransaction(transaction);
    }

    public List<Block> getBlockChainContent() {
        return new ArrayList<>(blockChain.getBlocks());
    }

    public Block startMining() {
        Block block = blockChain.mineBlock();
        blockChain.addBlock(block);
        return block;
    }
}