The four levels of visibility in Java (thing)

More specifically:

• Public access means that any object can directly access the variable or method.
• Protected access means that subclass objects, as well as members of classes in the same package, can access the thing being modified
• Package access means that classes within the same package can directly access that which is modified.
• Finally, the Private access modifier denies access to all objects not in the same class; practically speaking, almost always, even those should use accessor and mutator methods.