When you create an object in Java, such as in the following code:
Button b = new Button();
Java creates a new Button object in memory and sets the value of
variable b so that it points to this object on the heap. It also sets a
reference count to the object. When you are finished with the object set
the reference variable to null. This reduces the reference count and,
when the reference count reaches zero, the object's memory can be
reclaimed by Java's garbage collector.
Remember to set unused object references to null:
b = null;
to help out the Java garbage collector.