Java Visibility

From JavaProgramming.

Visibility of class members is almost the same as in C++, with a couple of important exceptions:

Default (no visibility specified)

• Not visible outside the class, except for classes in the same package
• Not visible from subclasses

Private

• Not visible outside the class
• Not visible from subclasses

Protected

• Not visible outside the class, except for classes in the same package
• Visible from subclasses

Public

• Visible outside the class
• Visible from subclasses

Here is a test program to demonstrate visibility:

/* TestVisibility.java */
class Classname {
int defaultVar;
public int publicVar;
protected int protectedVar;
private int privateVar;
}
public class TestVisibility {
public static void main(String[] args) {
Classname foo = new Classname();
foo.defaultVar++; // Visible within the package
foo.publicVar++; // Evidently public visibility
foo.protectedVar++; // Visible within the package!!!
foo.privateVar++; // Compiler error: privateVar has private access
}
}