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.

The next example shows how a 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