String swapping without temp var

// String swapping without temp variables:

// in PHP
function swap($a,$b)
{
	$a=$a.$b;
	$b=substr($a,0, strpos($a, $b));
	$a=substr($a,strlen($b),strlen($a));
	return array($a,$b);
}

// in Java
public static String[] swap(String a, String b)
{
	a=a.concat(b);
        b=a.substring(0,a.indexOf(b));
	a=a.substring(b.length(), a.length());
	return new String[]{a,b};
}