Public method and field access - Java Object Oriented Design

Java examples for Object Oriented Design:Access Level

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Description

Public method and field access

Demo Code

public class DeltaTwo {
    public static void main(String[] args) {
        Alpha a = new Alpha();
        //a.privateMethod();    //illegal
        //a.packageMethod();    //illegal
        //a.protectedMethod();  //illegal
        a.publicMethod(); //legal

        //System.out.format("privateVariable:   %2d%n",
        //  a.privateVariable);       //illegal
        //System.out.format("packageVariable:   %2d%n",
        //  a.packageVariable);       //illegal
        //System.out.format("protectedVariable: %2d%n",
        //  a.protectedVariable);   //illegal
        System.out.format("publicVariable:    %2d%n", a.publicVariable); //legal
    }//from   w  ww .j av a2  s .c o m
}
class Alpha {

    //member variables
    private int privateVariable = 1;
    int packageVariable = 2; //default access
    protected int protectedVariable = 3;
    public int publicVariable = 4;

    //methods
    private void privateMethod() {
        System.out.format("privateMethod called%n");
    }

    void packageMethod() { //default access
        System.out.format("packageMethod called%n");
    }

    protected void protectedMethod() {
        System.out.format("protectedMethod called%n");
    }

    public void publicMethod() {
        System.out.format("publicMethod called%n");
    }

    public static void main(String[] args) {
        Alpha a = new Alpha();
        a.privateMethod(); //legal
        a.packageMethod(); //legal
        a.protectedMethod(); //legal
        a.publicMethod(); //legal

        System.out.format("privateVariable: %2d%n", a.privateVariable); //legal
        System.out.format("packageVariable: %2d%n", a.packageVariable); //legal
        System.out.format("protectedVariable: %2d%n", a.protectedVariable); //legal
        System.out.format("publicVariable: %2d%n", a.publicVariable); //legal
    }
}
/*
 * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle or the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

Result


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