Question

I read (somewhere) that finalize() for a parent class is not guaranteed to be called when the subclass is garbage-collected, does this mean most developers override finalize() in the subclass and call super.finalize()?

Answer 1

Finalize is not automatically called for the super class. So if you override finalize, the proper way to ensure the super class gets cleaned up would be

protected void finalize() {
    try {
       // do subclass cleanup
    }
    finally {
       super.finalize();
    }
}

See this reference article http://www.ibm.com/developerworks/java/library/j-jtp06294/index.html

It should be worth noting that finalizers are not very predictable and you don’t have any control over if/when they run. Nothing critical should be done in finalize methods. In general it is better practice to just perform explicit cleanup of your class.