== Vs .equals()

[Clarence J M Tauro]

Consider the following code

  
a == b;
a.equals(b);

Is it the same, considering that the Object class's .equals() method being invoked?

[Steve Luke]

That depends on the runtime type of a.

If a's type is Object, 
  then yes they behave the same
else If (a's class does not override .equals()) AND (a does not subclass a class which overrides .equals())
  then yes they behave the same
else  //a overrides equals, or one of a's parent's type does 
  then no they behave differently

[Clarence J M Tauro]

Ha ha, Nice way to answer. Thanks a lot..

[Anirudh Aithal]

I found a nice article about this:
http://www.ccnyddm.com/JavaBook/EqualsEtc.htm

[Raj chiru]

The default behaviour (default implementation) of equals() is to do == comparisions.
if you do't override the equals() in a class ,no two objects can ever be consider equal since references to two different objects will always contain a
different pattern (i.e hash value is different)

[Chitta Ranjan Mahato]

    public class EqualTest {
    
    public static void main(String args[])
    {
        Integer i1 = new Integer(10);
        Integer i2 = new Integer(10);
        if(i1==i2)
        {
            System.out.print("equals");
        }
        
        else
        {
            System.out.println("not equal");
        }
    }
        
            

}
Output: not equals
public class EqualTest1 {
    
    public static void main(String args[])
    {
        Integer i1 = new Integer(10);
        Integer i2 = new Integer(10);
        if(i1.equals(i2))
        {
            System.out.print("equals");
        }
        
        else
        {
            System.out.println("not equal");
        }
    }
        
            

}
Output:equals

[Raj chiru]

In case of Wrapper classes it's true