Mega Code Archive
Specifying a Retention Policy
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A retention policy determines at what point an annotation is discarded.
SOURCE: annotation retained only in the source file and is discarded during compilation.
CLASS: annotation stored in the .class file during compilation, not available in the run time.
RUNTIME: annotation stored in the .class file and available in the run time.
They are defined java.lang.annotation.RetentionPolicy enumeration.
A retention policy is specified using Java's built-in annotations: @Retention.
@Retention(retention-policy)
the default policy is CLASS.
MyAnnotation uses @Retention to specify the RUNTIME retention policy.
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
// A simple annotation type.
@Retention(RetentionPolicy.RUNTIME)
@interface MyAnnotation {
String stringValue();
int intValue();
}
public class MainClass {
// Annotate a method.
@MyAnnotation(stringValue = "Annotation Example", intValue = 100)
public static void myMethod() {
}
}
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