Use of 'new' operator

Question

public void main()
Test obj=new Test();
obj.display();
obj= new Test("xyz",10,"agg");
/*why is new used again here when the object is already allocated with memory*/
obj.display();
Test is a predefined class. Why do we need to use 'new' operator again in the 3rd line???

Answer 1

public static void main(String[] args) {    
     Test obj=new Test();  
// creates a new Test object and assigns its reference to the variable "obj"
     obj.display();  
// calls the display() method on this object
     obj= new Test("xyz",10,"agg");  
// creates another, different Test object and re-assigns it to "obj".
// Any reference to the first Test object has been destroyed  
     obj.display();
// calls the display() method on the other Test object.
}