swap : Java Glossary

// swap int variables a and b
int a = 1;
int b = 2;
// save a copy of "a" you are about to clobber
int swap = a;
a = b;
b = swap;

// swap references a and b
Thing a = new Thing( 1 );
Thing b = new Thing( 2 );
// save a copy of "a" you are about to clobber
Thing swap = a;
a = b;
b = swap;
// avoid packratting Thing( 1 )
swap = null;

// Swap references a and b without a temporary
// It works on the principle that if you xor
// with something twice you
// get back to where you started.
// Note, this is slower than using a swap temp variable.
int a = 17;
int b = 42;
a = a ^ b;
b = a ^ b; // a ^ b ^ b = a
a = a ^ b; // a ^ b ^ a ^ b ^ b = b