== operator

[Gaurav Pavan Kumar Jain]

hi all

please let me know the functioning of == operator in refrence of object variable. Please specify example also

[Qunfeng Wang]

The "==" operator is used to determine if two references refer to the same object when object variables concerned.

Integer i1 = new Integer(10);
Integer i2 = new Integer(10);
 
System.out.println(i1 == i2); //false
System.out.println(i1.equals(i2));//true
 
...

[Saket Barve]

The == operator will check for reference equality whereas the .equals method will compare the actual values.

In the following code, "Different Reference" will be printed out.

    
 
Integer iValue = new Integer( 5 );
Double dValue = new Double( 5 );
 
if( iValue == dValue ) {
    System.out.println( " Same Reference" );
} else {
    System.out.println( " Different Reference ") ;
}
 

Here's a good link.

[Gaurav Pavan Kumar Jain]

Thank you for your suggestion

[Anupam Sinha]

By default equals() would also check for reference equality unless it is overridden.

[sadasiva kumar]

Use == operator to compare two primitives,or to see if two references refer to the same object.
Remember ,the == operator cares only about the pattern of bits in the variable.The rules are the same whether the variable is a reference or primitive.

Example : (1) Comparing two primitives

int a = 9;
byte b = 9;
if( a == b) { // true }

(2) Comparing two references

Zoom a = new Zoom();
Zoom b = new Zoom();
Zoom c = a;
if(a == b) { // false }
if(a == c) { // true }
if(b == c) { // false }

regards
SADASIVAKUMAR UTTI
SCJP1.4