Implementing the equals() Method

This short article contains the recent facts for implementing the equals() method of a class. If you are interested in the full explanation of the details, please take a look at the article from Angelika Langer: Implementing the equals() Method - Part 1 (german only, sorry).

This is the basic implementation for a class that is directly derived from java.lang.Object:

public boolean equals(final Object object) {
    if (this == object) {
        return true;
    }

    if (object == null) {
        return false;
    }

    if (getClass() != object.getClass()) {
        return false;
    }

    // TODO compare all fields of this class
    return true;
}

This is the basic implementation for a class that is NOT directly derived from java.lang.Object:

public boolean equals(final Object object) {
    if (this == object) {
        return true;
    }

    if (!super.equals(object)) {
        return false;
    }

    // TODO compare all fields of this class
    return true;
}