Is Java “pass-by-reference” or “pass-by-value”?

Java is always pass-by-value. Unfortunately, when we pass the value of an object, we are passing the reference to it. There is no such thing as “pass-by-reference” in Java. This is confusing to beginners.

The key to understanding this is that something like

Dog myDog;

is not a Dog; it’s actually a pointer to a Dog.

So when you have

Dog myDog = new Dog("Rover");
foo(myDog);

you’re essentially passing the address of the created Dog object to the foo method.