Java has a bug

Question

Hi
All variable pass into a function, shuould passed by value, so we are not able to change the original variable through the parameter. But something wrong here:
import javax.swing.tree.DefaultMutableTreeNode;
public class tt{
public static void main(String[] args){
     DefaultMutableTreeNode t=new DefaultMutableTreeNode("123");
ccc(t);
     System.out.println(t.getUserObject());
static private void ccc(DefaultMutableTreeNode a){
     a.setUserObject("456");
it should print 123, but it print 456. Should it be a bug of Java?
thanks from Peter ([email protected])

Answer 1

u have not understood the concept of object references thats y u feel its wrong..be careful when u make such statements.
When objects are passed to functions, its the object reference thats getting passed, and obviously the reference is passed by value.but using this reference, the function can point to the actual object in the heap and if any change is made..it reflects the actual object.
here..object reference is passed by value which gets allocated in the functions stack and it points to the actual object which is allocated in the heap.
hope its clear..its not a bug..
sandeep joseph