Unable to understand result of this code

[gurneeraj singh]

  class X {
           public static void main(String[ ] args) {
                     Boolean b1 = new Boolean( true );
                     boolean b2 = true;
                     Boolean b3 = Boolean.valueOf( "FALSE" );
                     Boolean b4 = Boolean.valueOf( "yes" );
 
                     if ( b1 & b2 || b3 | b4)//----> Line !
                              System.out.println( "Mercury" );
                     else
                              System.out.println( "Mars" );
           }
}
 

How we solve equation in line 1.

[ March 22, 2008: Message edited by: gurneeraj singh ]

[Jelle Klap]

The output will be "Mercury" and only the logic to the left of the || operator will ever be evaluated for the given boolean values.

You can read line 1 as:

if both b1 and b2 are true, execute the if-body immidiately.
OTHERWISE
if either b3 or b4 are true, or both are, execute the if-body.
OTHERWISE
execute the else body.

An equivalent if-else structure would be:

if(b1 & b2)
{
  System.out.println("Mercury");
}
else if(b3 | b4)
{
  System.out.println("Mercury");
}
else
{
  System.out.println("Mars");
}

Remeber that in the abscence of parentheses the order of precendence for boolean operators is (highst priority first):
1. &
2. |
3. &&
4. ||
[ March 22, 2008: Message edited by: Jelle Klap ]