The Deprecated Annotation in Java

In Java, the Deprecated annotation can be defined as an annotation that is utilized for indicating that a specific class, method, interface, or field should not be available to use. A deprecated element or entity is marked for indicating that is not available for usage anymore.

What is Deprecated Annotation in Java

As explained in the introduction, a deprecated element such as a class, field, method, or interface cannot be used by anyone. If an element gets deprecated, it becomes irrelevant. In simple words, a deprecated element is considered unimportant or useless.

The compiler gets notified by the deprecated annotation when any element or entity is deprecated, and the compiler will generate and throw a warning if any user tries to use the deprecated element.

Why Do We Use Deprecated Annotations in Java

Every program contains certain kinds of API for functioning. Over time, the Application Programming Interface of the project will change and evolve. Specific elements in the project such as methods, fields, classes, constructors, or types are not required to be used by the people or end-users.

The deprecated annotation in Java can be utilized for marking these specific elements as deprecated. Once an element is marked as deprecated, other users or developers get indicated that the marked element should not be used.

How To Deprecate an Element in Java?

The Deprecated annotation is majorly utilized for deprecating any element in Java.

In Java, an interface, class, method, members of class and constructor can be deprecated using the @Deprecated annotation.

Implementing Deprecation Annotation in Java

Let us understand more about Deprecation Annotation in Java with the help of a few example Java programs.

Example 1:

In this Java example program, we will be learning how to use a deprecated variable.

Filename: DeprecatedAnnotation1.java

// Java example program to demonstrate the features and functionalities of Deprecated Annotation in Java

public class DeprecatedAnnotation1{

@Deprecated

// Declaration and Initialization of Integer Variables
int SALARY = 50000;

// New Variable
int NEW_SALARY = 60000;

public static void main(String[] args) {

// Object creation of the Main JTP class
DeprecatedAnnotation1 o1 = new DeprecatedAnnotation1();

// Printing the value stored in the Integer variable
System.out.println(o1.SALARY);
}
}

Output:

Example 2:

In this Java example program, we will be learning how to use a deprecated method.

Filename: DeprecatedAnnotation2.java

// Java program for demonstrating the features and functionalities of Deprecated Annotation in Java

public class DeprecatedAnnotation2{

// With the help of Deprecated keyword, the PREVIOUS_METHOD will be replaced by
// the latest method LATEST_METHOD.
@Deprecated

// Method 1
// Old method
public void PREVIOUS_METHOD() {

// INSTRUCTIONS of the method
System.out.println("THIS METHOD IS DEPRECATED");
}

// Latest method which should be used
public void LATEST_METHOD() {

// INSTRUCTIONS of the method
System.out.println("THIS METHOD IS NOT DEPRECATED");
}

public static void main(String a[]) {

// Object creation of the Main JTP class
DeprecatedAnnotation2 o1 = new DeprecatedAnnotation2();

// Executing the previous method.
o1.PREVIOUS_METHOD();
}
}

Output:

THIS METHOD IS DEPRECATED

Example 3:

In this Java example program, we will be learning how to use a deprecated variable and a deprecated method.

Filename: DeprecatedAnnotation3.java

// Java program for demonstrating the features and functionalities of Deprecated Annotation
public class DeprecatedAnnotation3{

// The Latest method will replace the previously deprecated method
@Deprecated

// Declaration and initialization of Integer variables as class members.
int ROLL_NO = 47;
final int COUNT = 60;

@Deprecated

// PREVIOUS METHOD, which is deprecated and not relevant anymore.

public void PREVIOUS_METHOD() {

// Instructions of the Method
System.out.println("THIS METHOD IS DEPRECATED");
}

// Latest Method, which is relevant and will be replacing the Deprecated Method
public void NEW_METHOD() {

// Instructions of the Method
System.out.println("THIS METHOD IS NOT DEPRECATED");
}

public static void main(String a[]) {

// Object Creation of the Main JTP class
DeprecatedAnnotation3 obj = new DeprecatedAnnotation3();

// The Previous method is being executed.
obj.PREVIOUS_METHOD();

// Displaying the value stored in an integer variable
System.out.println(obj.ROLL_NO);
}
}

Output:

THIS METHOD IS DEPRECATED
47

Example 4:

In this Java example program, we will be learning how to use a deprecated variable and a deprecated constructor.

Filename: DeprecatedAnnotation4.java

// Java program to demonstrate the features and functionalities of Deprecated Annotation in Java.
import java.util.*;

public class DeprecatedAnnotation4{

// @deprecated
// The Class member or variable is declared and initialized and is Deprecated
// meaning it is not relevant.
@Deprecated

static int ID = 47;

// New Integer variable as Class Member
protected int NEW_ID = 48;

// @deprecated
// The first constructor is deprecated and will be replaced by the Second
// constructor.

// Old Constructor of the JTP class
DeprecatedAnnotation4 (int X, int Y, int Z) {

// Instructions of the constructor.
System.out.println("This Constructor is DEPRECATED");
}

// New Constructor of the JTP class
DeprecatedAnnotation4 (float X, int Y, float Z) {

// Instructions of the constructor.
System.out.println("This is the NEW CONSTRUCTOR");
}

public static void main(String X[]) {

// Object Creation of the Main class JTP
DeprecatedAnnotation4 obj = new DeprecatedAnnotation4 (ID, ID, ID);

// Displaying the value of the ID of the object created.
System.out.println(obj.ID);
}
}

Output: