What does the == operator compare in Java?

The == operator in Java is used to verify if two references point to the same object instance. This means that when you use this operator, you're checking whether both references are referring to the exact same memory location in the heap, not necessarily if the objects they point to are logically equivalent or have the same state.

For instance, if you create two different objects with the same attribute values, using == on these two object references would return false because they reside at different memory addresses.

In contrast, if you want to check whether two objects are equivalent in value or contain the same data, you would typically use the .equals() method, which is designed for that purpose. This understanding is crucial, as it helps avoid unintended behavior when comparing objects in Java.