What is the explanation for the different access modifiers in Java?

An Access Modifier is a key Word in Java that determines what level of access or visibility a particular Java variable/method or class has. There are 4 basic access modifiers in Java. They are:

1. Public
2. Protected
3. Unspecified (package-private)
4. Private

Classes can only be declared public or left unspecified (the "package-private" default level). Methods can be declared any of the above.

See the Link on the Java Tutorial for a very good explanation of the various levels of access each modifier provides.