This Java tutorial helps you understand the use of protected keyword in Java with code example.

Basically, the protected keyword is an access modifier for method and variable of a class.

When a method or a variable is marked as protected, it can be accessed from:

• •           Within the enclosing class.
  •           Other classes in the same package as the enclosing class.
  •           Sub classes, regardless of packages.

The main purpose of protected keyword is to have the method or variable can be inherited from sub classes.

 

Java protected keyword Examples:

The following class Person, declares a protected variable name, inside package p1:

package p1;

public class Person {
    protected String name;
}

The following class in the same package can access the variable name directly:

package p1;

public class Employer {
    void hireEmployee() {
        Person p = new Person();
        p.name = "Nam";    // access protected variable directly
    }
} 

The following class is in different package but it extends the Person class so it can access the variable name directly:

package p2;

import p1.Person;

class Employee extends Person {
    void doStuff() {
        name = "Bob";
    }
}

But the following class, in different package, cannot access the variable name directly:

package p2;

import p1.Person;

class AnotherEmployer {
    void hire() {
        Person p = new Person();
        // compile error, cannot acceess protected variable
        // from different package
        p.name = "Nam";
    }
}

The above code will cause compilation error:

AnotherEmployer.java:8: error: name has protected access in Person

 

Related keyword: public and private. See all keywords in Java.

 

Related Topics:

• Understand access modifiers in Java

 

Other Recommended Tutorials:

• 9 Rules about Constructors in Java
• 12 Rules and Examples About Inheritance in Java
• 12 Rules of Overriding in Java You Should Know
• 10 Java Core Best Practices Every Java Programmer Should Know
• Understand Interfaces in Java
• Understand how variables are passed in Java
• Understand encapsulation in Java