The isAnnotationPresent() method of java.lang.Package class is used to check if an annotation of the specified annotation type is present in this class. The method returns a boolean value starting 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 starting 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
