How to implement hashCode and equals method

Question

How should I implement hashCode() and equals() for the following class in Java?

class Emp 
{
  int empid ; // unique across all the         


        

Answer 1

Guava has helper methods for creating them. You tell it which fields to take in consideration and it will handle nulls for you and do the prime number calculation for hashcode.

IDEs can also generate them based on the fields you choose.

The advantage of delegating it to a tool like that is you get a standard solution and will worry less about bugs and maintenance of varied implementations spread all over your project.

Here's an example of using Guava and generated by an IntelliJ plugin: https://plugins.jetbrains.com/plugin/7244?pr=