Default Access Specifier in Java: A Detailed Guide

We define access specifiers as  Java’s keywords used to specify whether classes, methods, and variables are visible. These specifiers assist in determining how different program components work together and the trick to enforcing encapsulation and modularity. Java provides four main types of access specifiers:

• Public
• Private
• Protected
• Default(Package-Private)

In this article, we will explore the default access specifier in Java. This may sound confusing, but if no access specifier is given for a class, method, or variable, it is given package private access, meaning it is accessible only in the same package until further access properties are added and implemented. This specifier is commonly referred to as package-private, which restricts access to the package’s scope. To understand this concept with examples and explanations, let’s advance into it.

Also Read: Encapsulation in Java

Default Access Specifier in Java

A default access specifier (package-private) is used if you do not specify an access modifier. This is the most restrictive level of access after private, and it is used mainly to limit the visibility of members inside the same package.

Characteristics of the Default Access Specifier

• Package-Level Access: What that means is that if we declare a class, method, or variable as default, then only other classes of the same package can access it. It can not be accessed outside of this package or from classes other than those defined in the package.
• No Keyword Required: No keyword is used to apply the default access specifier. By default, Java gives any access modifier you do not specify (e.g., public, protected, or private).
• Common Usage: You can use it for classes and members that are supposed to be shared between packages but don’t want to be exposed to external packages. It helps better organize code in the same package while keeping things encapsulated.

The default access specifier can be applied to various elements in Java:

Classes

• Protecting top-level classes from each other is done by making them default accessible so that they can only be accessed by other classes inside the same package.
• Descendant packages can also see default access to inner classes (called nested classes).

Methods and Variables

• By default, its access specifier is package-private if a method or variable is declared without an access specifier. They are available only to classes in the same package, but not to other classes within the same package.

Also Read: Classes and Objects in Java

Syntax of Default Access Specifier

• The DefaultClass class has default access which means it’s accessible only for other classes inside the same package.
• The defaultMethod() method also has default access (only objects in the package can use it) and is also static, but you can ignore that and return a default.

Examples of Default Access Specifiers in Java

Usage in Classes

Accessing the Default Class Within the Package

Output:

Explanation:

Here of all classes, MyClass has default access meaning that it can be accessed from Main which is in the same package (prepbytes). This proves that in the same package, default access also works properly as the public method myMethod() is called well here.

Usage in Methods

Accessing the Default Method Within the Package

Output:

Explanation:

myMethod() here is a default method in MyClass. Because Main is in the same package, this works! It successfully calls the method and that means default methods can be used within the same package.

Usage in Variables

Accessing the Default Variable Within the Package

Output:

Explanation:

In this case, MyClass declares myVariable with default access. Since Main is in the same package it can use the default variable and print its value, showing us that default variables are accessible within the same package.

Also Read: Features of Java Programming Language

Advantages of Default Access Specifier

• Encapsulation Within Packages: It makes the package level restricted, hiding the implementation details and showing only what’s required.
• Modular Design: Then, such an interface provides a way to promote a modular approach because developers only expose the essential classes and methods, making it easier for code maintenance and management.
• Simplified API Design: Here we help to create the APIs by providing implementation details, which are not supposed to be known to other packages or modules.
• Performance Benefits: It allows for faster performance as access checks are done within the same package and decreases the overhead that simply checking access levels on multiple packages.
• Enhanced Security: Improves application security by preventing unauthorized access to package-level classes and methods.

Disadvantages of Default Access Specifier

• Limited Flexibility: When we need to access the class method or variable outside the package then it can be restrictive of package-level visibility.
• Tight Coupling Within Packages: If classes within the same package have dependencies on each other’s default members, their maintenance and refactoring can be complicated.
• Potential for Confusion: If developers are unaware of the default access level, they can think that members are public, and then misunderstand how to use, and how interact with classes.

Also Read: Java Interview Questions and Answers

Conclusion

Java’s fundamental concept is a default access specifier that dictates how class visibility and encapsulation will be managed inside a package. It limits package level visibility and helps to keep a clean architecture while at the same time limiting class interaction to a controlled environment. To build robust and maintainable Java applications, it is very important to understand how to use the default access specifier effectively and the other access specifiers. Enrol in the Certificate Program in Full Stack Development with Specialization for Web and Mobile powered by Hero Vired to get hands-on experience on Java.