Question

Is there any way to actually see the source code of standard java classes by the way? I’m making a hash table of points (HashSet<Point>) and I want to make sure that it will hash well, but I can’t see what Point’s hashCode() method actually looks like, so I don’t know how good it really is. Can anyone help me? Should I override it? And if so, is there an easy way to do this without creating a whole new java file/class?

Answer 1

If you’re searching for the hashCode() of java.awt.Point, it is defined in java.awt.geom.Point2D.

/**
 * Returns the hashcode for this <code>Point2D</code>.
 * @return      a hash code for this <code>Point2D</code>.
 */
public int hashCode() {
    long bits = java.lang.Double.doubleToLongBits(getX());
    bits ^= java.lang.Double.doubleToLongBits(getY()) * 31;
    return (((int) bits) ^ ((int) (bits >> 32)));
}

Note that the question “Will it hash well?” is hard to answer, it depends primarily on usage pattern.

You can access the source code of nearly all “standard Java classes”, just search for the src.zip file in your JDK installation directory (or use an IDE like Eclipse/NetBeans and click F3 on the class name).