Equals and ==

[hewitt charlotte]

The base implementation of equals method in the Object class checks for reference equality.

class equals
{
public static void main(String args[]) {
Object o1= new Object();
Object o2 = new Object();
o1=o2;
System.out.println(o1==o2);;
System.out.println(o1.equals(o2));;

}

}

Then why the result is : false and true .

[James Hambrick]

I just copied your code and ran it, I got true and true.

[marc weber]

Are you sure your "o1 = o2" assignment wasn't between the println statements when you got that output?

class Equals {
  public static void main(String args[]) {
    Object o1 = new Object();
    Object o2 = new Object();
    System.out.println(o1==o2);
    o1 = o2;
    System.out.println(o1.equals(o2));;
  }
}

[hewitt charlotte]

[hewitt charlotte]

class equals
{
public static void main(String args[]) {
Object o1= new Object();
Object o2 = new Object();
o1=o2;
System.out.println("== Magic " +o1==o2);;
System.out.println("== Magic " +o1.equals(o2));;

}

}
C:\mridul>javac equals.java

C:\mridul>java equals
false
== Magic true

C:\mridul>

Please help , why its coming wrong for me.

[Bob Ruth]

System.out.println("== Magic " +o1==o2);;

This is merely a guess.... I have read something about the concatenationf of strings with the variables following them... and I wonder if precedence is getting int he way here.

If this string is being interpreted as "== Magic " + o1 (and the 01 is getting converted to string and concatenated to the "== Magic " string and THEN the == comparison is running against Object o2 and of course it will not equal! What made me suspicious is that the "== Magic " string doesnt even show up in the console output.

Try this instead.... just as a test....

System.out.println("== Magic " + (o1==o2));;

notice the extra parens around o1==o2....

give it a shot...

[marc weber]

Originally posted by hewitt charlotte:
...why its coming wrong for me.

That's an entirely different situation, which was answered when you posted the same question last weekend.