Ondra Žižka Ondra Žižka - 5 months ago 17
Java Question

Java: Automatic equals() and hashCode()

Implementing

equals()
and
hashCode()
for simple data POJOs is cluttering my code and maintaining is tedious.

What are the libraries handling this automatically?

I prefer bytecode instrumentation over AOP approach due to performance reasons.

Update: Topic of necessity of implementing equals() and hashCode() has been discussed, here's my point:

Isn't it better to have it done right upfront with minimal effort rather than digging in the code, adding hC/eq when it comes to it?

Answer

Project Lombok provides the annotation @EqualsAndHashCode which will generate equals() and hashCode() for your Java classes. Of course there are some drawbacks in comparison to manually implementing these methods, so make sure you read the "small print" on the linked page.