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 annotations 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());
// 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-