Great question! You can think of Bitcoin, HyperLedger and Corda as 3 different flavors of blockchain, each with different set of features. BitcoinJ is an implementation of the Bitcoin protocol initially defined by Satoshi Nakamoto in a whitepaper and evolved over a decade by the Bitcoin dev community. HyperLedger and Corda borrow ideas from Bitcoin and discard other ideas and focus on blockchain that is more useful in the enterprise. For example, Bitcoin espouses the idea of transactions being open and public, anyone can see transactions occurring although they may not know who is truly behind those transactions. For enterprise situations, this may not be ideal. Instead, KYC is required and who a business is transacting with cannot be anonymous. In addition, most businesses want their transactions with other businesses to be private and not public. HL and Corda therefore focus on private transactions.
For some sort of clarity let me outline some of the different types of blockchain/decentralised ledger technology systems and the business case for them.
Open or closed would describe who can view (or read) the data. An open system would show all the data to anyone, a closed system would restrict who can see this data.
Public or private would determine who can write (or create) data. For public this would be anyone, private systems would add restrictions.
So an open and public systems tend to be used for cryptocurrencies that offer a store of value (bitcoin), payment services (ripple), or programmable networks (ethereum/de-fi). Data is identified by using a public address but owned by the person who holds the private key.
A closed and private network like Corda [and Hyperledger Fabric] would require some sort of identity access management. Typically participants only share a subset of their data with relevant customers as it may be commercially sensitive (Alice may not want Oscar to know that Bob pays less for a widget). Trade finance, supply chain, or any system which would benefit from "trusted" shared data would be the typical use case.
An open and private system would suit the publication of laws, publicly viewable tax returns, public announcements, and similar. Closed and public would suit voting use cases.
...and then there are central bank digital currencies (CBDC) - but that's a whole new topic!