The isAnnotationPresent() method of java.lang.Class class is used to check if an annotation of the specified annotation type is present in this class. The method returns a boolean value stating the same.
Syntax:
public boolean isAnnotationPresent(Class<T> annotationClass)
Parameter: This method accepts a parameter annotationClass which is the type of the annotation to get.
Return Value: This method returns boolean value stating the same.
Exception: This method throws:
- NullPointerException: if the given annotation class is null.
Below programs demonstrate the isAnnotationPresent() method.
Example 1:
// Java program to demonstrate// isAnnotationPresent() 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 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()); // Check if there is any annotation // using isAnnotationPresent() method System.out.println( "If there is any annotation in myClass: " + myClass.isAnnotationPresent( Annotation.class)); }} |
Output:
Class represented by myClass: class Test If there is any annotation in myClass: true
Example 2:
// Java program to demonstrate// isAnnotationPresent() method import java.util.*;import java.lang.annotation.*; // Class with no annotationspublic class Test { 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 isAnnotationPresent() method System.out.println( "If there is any annotation in myClass: " + myClass.isAnnotationPresent( Annotation.class)); }} |
Output:
Class represented by myClass: class Test If there is any annotation in myClass: false
Reference: https://docs.oracle.com/javase/9/docs/api/java/lang/Class.html#isAnnotationPresent-java.lang.Class-
