Soft Parse
The Oracle parse path that reuses an existing compatible cursor rather than performing a full hard parse, while still incurring some lookup and validation work.
Oracle Runtime Context
A soft parse reuses an existing compatible cursor instead of performing all work required for a hard parse. It is cheaper, but still involves library-cache lookup, validation, and other per-call work, so an extremely high parse-call rate can remain a scalability issue.
Cache Boundary
Soft parsing and client statement caching are not the same mechanism. A JDBC or driver statement cache can avoid issuing many parse calls in the first place.