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 
  },
},