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java.lang.reflect.Field.getAnnotation() Method Example
Description
The java.lang.reflect.Field.getAnnotation(Class<T> annotationClass) method returns this element's annotation for the specified type if such an annotation is present, else null.
Declaration
Following is the declaration for java.lang.reflect.Field.getAnnotation(Class<T> annotationClass) method.
public <T extends Annotation> T getAnnotation(Class<T> annotationClass)
Parameters
annotationClass − the Class object corresponding to the annotation type.
Returns
this element's annotation for the specified annotation type if present on this element, else null.
Exceptions
NullPointerException − if the given annotation class is null.
Example
The following example shows the usage of java.lang.reflect.Field.getAnnotation(Class<T> annotationClass) method.
package com.tutorialspoint; import java.lang.annotation.Annotation; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.reflect.Field; public class FieldDemo { public static void main(String[] args) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException { Field field = SampleClass.class.getField("sampleField"); Annotation annotation = field.getAnnotation(CustomAnnotation.class); if(annotation instanceof CustomAnnotation){ CustomAnnotation customAnnotation = (CustomAnnotation) annotation; System.out.println("name: " + customAnnotation.name()); System.out.println("value: " + customAnnotation.value()); } } } @CustomAnnotation(name = "SampleClass", value = "Sample Class Annotation") class SampleClass { @CustomAnnotation(name="sampleClassField", value = "Sample Field Annotation") public String sampleField; public String getSampleField() { return sampleField; } public void setSampleField(String sampleField) { this.sampleField = sampleField; } } @Retention(RetentionPolicy.RUNTIME) @interface CustomAnnotation { public String name(); public String value(); }
Let us compile and run the above program, this will produce the following result −
name: sampleClassField value: Sample Field Annotation
java_reflect_field.htm
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