Finalizing Java Objects

The Java run-time system includes a garbage collector which automatically destroys unwanted objects. The garbage collector deletes any object which is not referenced by any other object. Once you have a proxy to a Java object in a COBOL program, the COBOL run-time system has a reference to the Java object which prevents the Java garbage collector from removing it.

When you have finished with a Java object, you must release the reference to it so that the garbage collector can delete the object - otherwise your application has a memory leak. To finalize the object:

invoke javaobject "finalize" returning javaobject

The returning parameter is important, as otherwise the COBOL run-time system passes the message on to the actual Java object instead of destroying the COBOL proxy. If the message is passed to the Java object, it invokes this function:

public void finalize()

This function is either inherited or implemented by all Java classes, and is called by the Java garbage collector before it destroys an object.

In the unlikely event that your Java class implements a finalize() method which returns a value, use the "delete" method to destroy the OO COBOL proxy instead:

invoke javaobject "delete" returning javaobject