In Java, everything is passed by value, including object references.

When a method is called and an object reference is passed as an argument, the reference is copied and passed to the method. This means that the method receives a copy of the reference to the object, not a copy of the object itself.

If the method modifies the state of the object (i.e., changes the values of its instance variables), those changes will be reflected in the original object because both the original reference and the copy point to the same object in memory. However, if the method reassigns the reference to a new object, that change will not be reflected in the original object, since the original reference still points to the original object.

In summary, Java is pass-by-value, but for object references, the value being passed is a copy of the reference, not the object itself.