Why Java does not allow overriding equals(Object) in an Enum?

Question

I\'ve noticed that the following snippet...

@Override
public boolean equals(Object otherObject) {
    ...
}

...is not allowed for an Enum,

Answer 1

Sometimes we need to deal with data that does not conform to Java naming standards. It would be nice to be able to do something like this:

public enum Channel
{
    CallCenter("Call Center"),
    BankInternal("Bank Internal"),
    Branch("Branch");

    private final String value;

    Channel(String value)
    {
        this.value = value;
    }

    @Override
    public String toString()
    {
        return value;
    }

    public static Channel valueOf(String value)
    {
        for (Channel c : Channel.values())
            if (c.value.equals(value))
                return c;
        return null;
    }

    @Override
    public boolean equals(Object other) 
    {
        if (other instanceof String)
            other = Channel.valueOf((String)other);
        return super.equals(other);
    }
}

The "String" class would need to be modified to accommodate...

public boolean equals (Object object) {
    if (object == this) return true;
    if (object instanceof Enum) 
        object = object.toString();
    if (object instanceof String) {
        String s = (String)object;
        // There was a time hole between first read of s.hashCode and second read
        //  if another thread does hashcode computing for incoming string object
        if (count != s.count ||
            (hashCode != 0 && s.hashCode != 0 && hashCode != s.hashCode))
                return false;
        return regionMatches(0, s, 0, count);
    }
    return false;
}