Which of the following access modifier can be accessed with in a class private protected public?

In object-oriented programming, the concept of 'Encapsulation' is used to make class members public or private i.e. a class can control the visibility of its data members. This is done using access modifiers.

There are three types of access modifiers in TypeScript: public, private and protected.

public

By default, all members of a class in TypeScript are public. All the public members can be accessed anywhere without any restrictions.

class Employee { public empCode: string; empName: string; } let emp = new Employee(); emp.empCode = 123; emp.empName = "Swati";

In the above example, empCode and empName are declared as public. So, they can be accessible outside of the class using an object of the class.

Please notice that there is not any modifier applied before empName, as TypeScript treats properties and methods as public by default if no modifier is applied to them.

private

The private access modifier ensures that class members are visible only to that class and are not accessible outside the containing class.

class Employee { private empCode: number; empName: string; } let emp = new Employee(); emp.empCode = 123; // Compiler Error emp.empName = "Swati";//OK

In the above example, we have marked the member empCode as private. Hence, when we create an object emp and try to access the emp.empCode member, it will give an error.

protected

The protected access modifier is similar to the private access modifier, except that protected members can be accessed using their deriving classes.

class Employee { public empName: string; protected empCode: number; constructor(name: string, code: number){ this.empName = name; this.empCode = code; } } class SalesEmployee extends Employee{ private department: string; constructor(name: string, code: number, department: string) { super(name, code); this.department = department; } } let emp = new SalesEmployee("John Smith", 123, "Sales"); emp.empCode; //Compiler Error

In the above example, we have a class Employee with two members, public empName and protected property empCode. We create a subclass SalesEmployee that extends from the parent class Employee. If we try to access the protected member from outside the class, as emp.empCode, we get the following compilation error:

error TS2445: Property 'empCode' is protected and only accessible within class 'Employee' and its subclasses.

In addition to the access modifiers, TypeScript provides two more keywords: readOnly and static. Learn about them next.

Want to check how much you know TypeScript?

Java access modifiers are used to provide access control in java. Java provides access control through three keywords - private, protected and public. We are not required to use these access modifiers always, so we have another one namely “default access”, “package-private” or “no modifier”.

Java Access Modifiers

Which of the following access modifier can be accessed with in a class private protected public?
We can use java access modifiers with Classes as well as Class variables and methods. We are allowed to use only “public” or “default” access modifiers with java classes.

  1. If a class is “public” then we can access it from anywhere, i.e from any other class located in any other packages etc.
  2. We can have only one “public” class in a source file and file name should be same as the public class name.
  3. If the class has “default access” then it can be accessed only from other classes in the same package.

Java Access Modifiers with Class Member

We can have all the four access modifiers for class member variables and methods. However, member access modifier rules get applied after the class level access rules. For example, if a class is having default access then it will not be visible in other packages and hence methods and variables of the class will also be not visible. We will look into each of them separately and then we will show the java access modifiers usage with a simple program.

Java Access Modifiers - public keyword

If a class member is “public” then it can be accessed from anywhere. The member variable or method is accessed globally. This is the simplest way to provide access to class members. However, we should take care of using this keyword with class variables otherwise anybody can change the values. Usually, class variables are kept as private and getter-setter methods are provided to work with them.

Java Access Modifiers - private keyword

If a class member is “private” then it will be accessible only inside the same class. This is the most restricted access and the class member will not be visible to the outer world. Usually, we keep class variables as private and methods that are intended to be used only inside the class as private.

Java Access Modifiers - protected keyword

If class member is “protected” then it will be accessible only to the classes in the same package and to the subclasses. This modifier is less restricted from private but more restricted from public access. Usually, we use this keyword to make sure the class variables are accessible only to the subclasses.

Java Access Modifiers - default access

If a class member doesn’t have any access modifier specified, then it’s treated with default access. The access rules are similar to classes and the class member with default access will be accessible to the classes in the same package only. This access is more restricted than public and protected but less restricted than private. (Least Accessible) private < default < protected < public (Most Accessible) The below table summarise above access modifiers with respect to different classes in the same package or other packages and subclasses.

Which of the following access modifier can be accessed with in a class private protected public?
Let’s write some simple classes where we will see the java access modifiers in action. TestA.java

package com.journaldev.access; class TestA { public void methodPublic(){ methodPrivate(); } protected void methodProtected(){ methodPrivate(); } void methodDefault(){ methodPrivate(); } private void methodPrivate(){} }

Note that TestA class has default access and the private class method is accessible to all other parts of the same class. TestB.java

package com.journaldev.access; import com.journaldev.access.TestA; public class TestB { public static void main(String args[]) { new TestA().methodPublic(); new TestA().methodProtected(); new TestA().methodDefault(); } public void methodPublic() { } protected void methodProtected() { } void methodDefault() { } private void methodPrivate() { } }

Note that TestB is in the same package as TestA class and hence it is able to access it’s class members. private members are not accessible but all other members are accessible because of the same package. TestC.java

package com.journaldev.access.child; import com.journaldev.access.TestB; public class TestC { public static void main(String[] args) { new TestB().methodPublic(); } }

TestB class is accessible because it’s public. Only public members of TestB class is accessible because TestC class is not in the same package nor its subclass of TestB. TestE.java

package com.journaldev.util; import com.journaldev.access.TestB; public class TestE extends TestB { public static void main(String[] args) { new TestB().methodPublic(); new TestB().methodProtected(); // compile time error // works, accessing super class protected method using subclass new TestE().methodProtected(); } }

Since TestE class is a subclass of TestB, we can access TestB protected members through child class TestE. If we try to access the superclass protected method directly, we will get a compile-time error. That’s all for the java access modifiers, it’s simple to understand. Just don’t confuse with the default and protected access. An easy way to remember is that default access is more restricted than protected and protected members are accessible in subclasses. Recently I made a video to explain java access modifiers in detail, you can watch it below on YouTube. https://www.youtube.com/watch?v=QKjnbC3UBtY

Which of the following access modifier can be accessed within a class?

For members, there are two additional access modifiers: private and protected . The private modifier specifies that the member can only be accessed in its own class.

Which of the following can be used as access modifier of a method private/public protected default?

Types of Access Modifier.

Which of the following can be used as access modifier of a method?

An access modifier is a modifier which restricts the access of a class, constructor, data member and method in another class.So, we have four access modifiers: - default , private , protected , and public . public - in this modifier , the members, methods and classes are declared public can be accessed from anywhere.

Can we use private access modifier for class?

Private Access Modifier - Private Class and interfaces cannot be private. Variables that are declared private can be accessed outside the class, if public getter methods are present in the class. Using the private modifier is the main way that an object encapsulates itself and hides data from the outside world.