How to synchronize a java method called by PL/SQL

Question

I just have a problem relative to concurrency whose logic flow is when a client (called Oracle Forms) will submit a request （called concurrent program ) and call a plsql procedu

Answer 1

I have no idea how the JVM inside the Oracle DB is implemented, but since (at least in some common configurations) every database connection gets its own server process, then if a separate JVM is embedded into each of those, a synchronized block won't do you much good. You'd need to use database locks.