why equals() method when we have == operator?

java equals referenceequals
GuruKulki picture GuruKulki · May 5, 2010 · Viewed 10.2k times · Source

When i see the implementation of equals() method it does nothing but same as what == does. So my question is what was the need to have this as separate method when we have == operator which does the same work?

Answer

Thomas Lötzer picture Thomas Lötzer · May 5, 2010

You can not overload the == operator, but you can override equals(Object) if you want it to behave differently from the == operator, i.e. not compare references but actually compare the objects (e.g. using all or some of their fields).

Also, if you do override equals(Object), have a look at hashCode() as well. These two methods need to be compatible (i.e. two objects which are equal according to equals(Object) need to have the same hashCode()), otherwise all kinds of strange errors will occur (e.g. when adding the objects to a set or map).

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