Options for automating Equals and Hashcode generation in Java (Number #3 BLEW MY MIND!)

1. Your IDE. I would not recommend it for most objects as they can slowly drift out of date with the actual class definition. They also look ugly and pollute your codebase with boilerplate code.
2. Apache Commons has a bunch of stuff for making this easier, including a reflective version so no risk of drifting out of date with the class definition. It is better than #1 unless you require a speedy equals/hashcode, but still too much boilerplate for my liking. 
3. Project Lombok and annotation processing. Whack an EqualsAndHashCode annotation on ya class and be done with it. I recommend using Project Lombok. It adds a touch of magic into the build (but not much) and so requires a plugin for your IDE to behave nicely but they are a small price to pay for no boilerplate code. Lombok is an annotation processor that run at compile time so you have no runtime performance hit.
4. Using a different language that supports it out the box, but also targets the JVM. Groovy uses an annotation and Kotlin supports data classes. Unless your existing code can quickly be converted, I would avoid this.
5. Google's Auto has an AutoValue. Like Project Lombok this is an annotation processor, however has less magic at the expense of little more boilerplate (thanks to Louis Wasserman).

This post is a repost of my answer on Stack Overflow.