This parameter determines the maximum size of the heap that is used by the Java interpreter.
There is one heap for each DB2 process (one for each agent or subagent on UNIX-based platforms, and one for each instance in other platforms), and there is also one heap for each fenced UDF and fenced stored procedure process. In all situations, only the agents or processes that run Java UDFs or stored procedures ever allocate this memory. On partitioned database systems, the heap is multiplied by the number of database partition servers.