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Rule:  Basic10Checked automatically with code checker

Synopsis:Ensure you override both equals() and hashCode()
Language:Java
Severity Level:2
Category:Basic


Description:
Override both public boolean Object.equals(Object other), and public int Object.hashCode(), or override neither. Even if you are inheriting a hashCode() from a parent class, consider implementing hashCode and explicitly delegating to your superclass.
// this is bad
public class Bar {
  public boolean equals(Object o) {
      // do some comparison
  }
}

// and so is this
public class Baz {
  public int hashCode() {
      // return some hash value
  }
}

// this is OK
public class Foo {
  public boolean equals(Object other) {
      // do some comparison
  }
  public int hashCode() {
      // return some hash value
  }
}