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-
