Public vs Private vs Protected vs Default in Java: Key Differences

In Java, public members are accessible from anywhere, private members only within their own class, protected members within the same package and subclasses, and default (no modifier) members only within the same package. These access levels control how classes and their members can be accessed to protect data and organize code.

Quick Comparison

This table summarizes the visibility of each access modifier in Java.

Access Modifier	Class	Package	Subclass (same or different package)	World (anywhere)
public	Yes	Yes	Yes	Yes
private	Yes	No	No	No
protected	Yes	Yes	Yes	No
default (no modifier)	Yes	Yes	No	No

Key Differences

public means the member or class is visible everywhere, so any other class can access it regardless of package.

private restricts access strictly to the defining class, hiding details from all other classes even in the same package.

protected allows access within the same package and also to subclasses outside the package, supporting inheritance while limiting general access.

default (no modifier) restricts access to classes within the same package only, providing package-level encapsulation.

Code Comparison

java

package example;

public class AccessDemo {
    public String publicVar = "Public";
    private String privateVar = "Private";
    protected String protectedVar = "Protected";
    String defaultVar = "Default"; // no modifier

    public void show() {
        System.out.println(publicVar);
        System.out.println(privateVar);
        System.out.println(protectedVar);
        System.out.println(defaultVar);
    }
}

class Test {
    public static void main(String[] args) {
        AccessDemo obj = new AccessDemo();
        System.out.println(obj.publicVar);      // Accessible
        // System.out.println(obj.privateVar);  // Error: private
        System.out.println(obj.protectedVar);   // Accessible (same package)
        System.out.println(obj.defaultVar);     // Accessible (same package)
    }
}

Output

Public
Protected
Default

Subclass Equivalent

java

package example.sub;

import example.AccessDemo;

public class SubClass extends AccessDemo {
    public void testAccess() {
        System.out.println(publicVar);      // Accessible
        // System.out.println(privateVar);  // Error: private
        System.out.println(protectedVar);   // Accessible (subclass)
        // System.out.println(defaultVar);  // Error: default not visible outside package
    }

    public static void main(String[] args) {
        SubClass sub = new SubClass();
        sub.testAccess();
    }
}

Output

Public
Protected

When to Use Which

Choose public when you want your class or member to be accessible from anywhere, such as API methods.

Use private to hide internal details and protect data within the class itself.

protected is best when you want to allow subclasses to access members but keep them hidden from unrelated classes.

Use default (no modifier) to share members only within the same package, useful for grouping related classes without exposing them globally.

Key Takeaways

Public members are accessible from any class in any package.

Private members are only accessible within their own class.

Protected members are accessible in the same package and subclasses outside the package.

Default access restricts visibility to the same package only.

Choose access modifiers based on how much you want to expose your class members.