The private keyword is an access control modifier that may be applied to a class, a method or a field (a variable declared in a class).
public class MyPublicClass { private class MyPrivateClass { } private int i; private String myMethod() { <statements> } }
A private (inner) class, method or field may only be referenced from within the class in which it is declared. It is not visible outside the class or to subclasses.
The default access for all class members is package access, meaning that unless a specific access control modifier is present the class members are accessible from within any class in the same package.