Garbage collection of unused objects

Java objects do not need to be explicitly destroyed; as long as an object is referenced by a variable, on the stack or in an expression, it will remain. When the last reference to an object is removed, the object is destroyed automatically.

This example shows how an unique object can be referenced twice, using two variables:

FUNCTION test()
  -- Declare 2 variables to reference a StringBuffer object
  DEFINE sb1, sb2 java.lang.StringBuffer
  -- Create object and assign reference to variable
  LET sb1 = StringBuffer.create()
  -- Same object is now referenced by 2 variables
  LET sb2 = sb1
  -- Object is modified through first variable
  CALL sb1.append("abc")
  -- Object is modified through second variable
  CALL sb2.append("def")
  -- Shows content of StringBuffer object
  DISPLAY sb1.toString()
  -- Same output as previous line 
  DISPLAY sb2.toString()
  -- Object is only referenced by second variable
  LET sb1 = NULL
  -- sb2 removed from stack, object is no longer referenced and is destroyed.
END FUNCTION