Java class Access Control

Introduction

Java's access modifiers are public, private, and protected.

Java also defines a default access level. If we do not specify any access modifiers, Java uses default value access control.

protected is applied for inheritance.

public

When a member of a class is modified by public, the member can be accessed by any other code.

private

When a member of a class is specified as private, the member can only be accessed by its class.

Here is an example: 

public int i;  
private double j;  
           
private int myMethod(int a, char b) {
  //...
}

Here is an example to illustrate the the effects of public and private access: 

//demonstrates the difference between public and private.
class Test {/*from  w ww.ja  va2 s.co  m*/
  int a; // default access
  public int b; // public access
  private int c; // private access

  // methods to access c
  void setc(int i) { // set c's value
    c = i;
  }
  int getc() { // get c's value
    return c;
  }
}
  
public class Main {
  public static void main(String args[]) {
    Test ob = new Test();

    // These are OK, a and b may be accessed directly
    ob.a = 10;
    ob.b = 20;

    // ob.c = 100; // Error!

    // You must access c through its methods
    ob.setc(100); // OK
   
    System.out.println("a, b, and c: " + ob.a + " " +
                       ob.b + " " + ob.getc());
  }
}

Inside the Test class, a uses default access.

b is specified as public.

c has private access.




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