Java protected keyword

A Java protected keyword is an access modifier. It can be assigned to variables, methods, constructors and inner classes.

Points to remember

The protected access modifier is accessible within the package. However, it can also accessible outside the package but through inheritance only.
We can't assign protected to outer class and interface.
If you make any constructor protected, you cannot create the instance of that class from outside the package.
If you are overriding any method, overridden method (i.e., declared in the subclass) must not be more restrictive.
According to the previous point, if you assign protected to any method or variable, that method or variable can be overridden to sub-class using public or protected access modifier only.

Examples of protected keyword

Example 1

Let's see an example to determine whether the protected variable is accessible or not outside the package.

//save by A.java
package com.java;

public class A {

 protected String msg="Try to access the protected variable outside the package";
	 
}
//save by ProtectedExample1.java
package com.javatpoint;
import com.java.A;

public class ProtectedExample1 {
public static void main(String[] args) {
	A a=new A();
   System.out.println(a.msg);
	
}
}

Output:

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
	The field A.msg is not visible

Example 2

Let's see an example to determine whether the protected variable is accessible or not outside the class and within the package.

class A {

 protected String msg="Try to access the protected variable outside the class within the package";
	 
}

public class ProtectedExample2 {
public static void main(String[] args) {
	A a=new A();
   System.out.println(a.msg);
	
}
}

Output:

Try to access the protected variable outside the class within the package

Example 3

Let's see an example to determine whether the protected method is accessible or not outside the package.

//save by A.java
package com.java;

public class A {

protected void msg()
 {
	 System.out.println("Try to access the protected method outside the package ");
 }
	 
}
//save by ProtectedExample3.java
package com.javatpoint;
import com.java.A;

public class ProtectedExample3 {
public static void main(String[] args) {
	A a=new A();
   a.msg();
	
}
}

Output:

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
	The method msg() from the type A is not visible

Example 4

Let's see an example to determine whether the protected method is accessible or not outside the package using inheritance.

//save by A.java
package com.java;

public class A {

protected void msg()
 {
	 System.out.println("Try to access the protected method outside the package using inheritance");
 }
	 
}
//save by ProtectedExample4.java
package com.javatpoint;
import com.java.A;

public class ProtectedExample4 extends A {
public static void main(String[] args) {
	ProtectedExample4 a=new ProtectedExample4();
   a.msg();
	
}
}

Output:

Try to access the protected method outside the package using inheritance

Example 5

Let's see an example to determine whether we assign protected to the outer class.

protected class ProtectedExample5 {
void display()
{
	System.out.println("Try to access outer protected class");
}
public static void main(String[] args) {
	ProtectedExample5 p=new ProtectedExample5();
	p.display();
	
}
}

Output:

Exception in thread "main" java.lang.Error: Unresolved compilation problem:

Example 6

Let's see an example to determine whether we create the instance of protected constructor from outside the class.

//save by A.java

package com.java;

public class A
{
 String msg;
protected A(String msg)
 {
	this.msg=msg;
 }
public void display()
{
	System.out.println(msg);
}
	 
}
//save by ProtectedExample6.java
package com.javatpoint;
import com.java.A;
	
public class ProtectedExample6 {
public static void main(String[] args) {
	A a=new A("Try to create the instance of protected constructor outside the package");	
	a.display();

	
}
}

Output:

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
	The constructor A(String) is not visibles

Example 7

Let's see an example to determine whether the protected method is overridden to sub-class using protected access modifier.

//save by A.java

class A
{
	protected void msg()
	{
		System.out.println("Try it");
	}
}
//save by ProtectedExample7.java
class ProtectedExample7 extends A {
	protected void msg()
{
	System.out.println("Try to access the overridden method");
}
public static void main(String[] args) {
	ProtectedExample7 p=new ProtectedExample7();
	p.msg();
	
}
}

Output:

Try to access the overridden method

Example 8

Let's see an example to determine whether the protected method is overridden to sub-class using private access modifier.

class A
{
	protected void msg()
	{
		System.out.println("Try it");
	}
}

class ProtectedExample8 extends A {
	private void msg()
{
	System.out.println("Try to access the overridden method");
}
public static void main(String[] args) {
	ProtectedExample8 p=new ProtectedExample8();
	p.msg();
	
}
}

Output:

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
	Cannot reduce the visibility of the inherited method from A

Example 9

Let's see an example to determine whether the protected method is overridden to sub-class using default access modifier.

class A
{
	protected void msg()
	{
		System.out.println("Try it");
	}
}

class ProtectedExample8 extends A {
	void msg()
{
	System.out.println("Try to access the overridden method");
}
public static void main(String[] args) {
	ProtectedExample9 p=new ProtectedExample9();
	p.msg();
	
}
}

Output:

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
	Cannot reduce the visibility of the inherited method from A

Example 10

Let's see an example to determine whether the protected method is overridden to sub-class using public access modifier.

class A
{
	protected void msg()
	{
		System.out.println("Try it");
	}
}

class ProtectedExample10 extends A {
	public void msg()
{
	System.out.println("Try to access the overridden method");
}
public static void main(String[] args) {
	ProtectedExample10 p=new ProtectedExample10();
	p.msg();
	
}
}

Output: