Class getAnnotationsByType() method in Java with Examples

The getAnnotationsByType() method of java.lang.Class class is used to get the annotations of the specified annotation type present in this class. The method returns an array of annotations for the specified annotation type.

Syntax:

public A[] getAnnotationsByType(Class<T> annotationClass)

Parameter: This method accepts a parameter annotationClass which is the type of the annotation to get.

Return Value: This method returns an array of annotations for the specified annotation type.

Exception: This method throws:

• NullPointerException: if the given annotation class is null.

Below programs demonstrate the getAnnotationsByType() method.

Example 1:

// Java program to demonstrate
// getAnnotationsByType() method

import java.util.*;
import java.lang.annotation.*;

// create a custom Annotation
@Retention(RetentionPolicy.RUNTIME)
@interface Annotation {

    // This annotation has two attributes.
    public String key();

    public String value();
}

// call Annotation for method
// and pass values for annotation
@Annotation(key = "GFG", value = "GeeksForGeeks")
public class Test {

    public Object obj;

    public static void main(String[] args)
        throws ClassNotFoundException
    {

        // returns the Class object for this class
        Class myClass = Test.class;

        System.out.println(
            "Class represented by myClass: "
            + myClass.toString());

        // Get the annotation
        // using getAnnotationsByType() method
        System.out.println(
            "Annotation of myClass of type Annotation: "
            + Arrays.toString(
                  myClass
                      .getAnnotationsByType(
                          Annotation.class)));
    }
}

Output:

Class represented by myClass: class Test
Annotation of myClass of type Annotation: [@Annotation(key=GFG, value=GeeksForGeeks)]

Example 2:

// Java program to demonstrate
// getAnnotationsByType() method

import java.util.*;
import java.lang.annotation.*;

@Deprecated
public class Test {

    public Object obj;

    public static void main(String[] args)
        throws ClassNotFoundException
    {
        try {
            // returns the Class object for this class
            Class myClass = Test.class;

            System.out.println(
                "Class represented by myClass: "
                + myClass.toString());

            // Get the annotation
            // using getAnnotationsByType() method
            System.out.println(
                "Annotation of myClass of type Deprecated: "
                + Arrays.toString(
                      myClass
                          .getAnnotationsByType(
                              Deprecated.class)));
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

Class represented by myClass: class Test
Annotation of myClass of type Deprecated: [@java.lang.Deprecated()]

Reference: https://docs.oracle.com/javase/9/docs/api/java/lang/Class.html#getAnnotationsByType-java.lang.Class-