Method: setAccessible(boolean flag)
import java.lang.reflect.Constructor; import java.lang.reflect.Field; import java.lang.reflect.Method; public class Main { public static void main(String[] argv) throws Exception { Class cls = java.lang.String.class; Method method = cls.getMethods()[0]; Field field = cls.getFields()[0]; Constructor constructor = cls.getConstructors()[0]; field.setAccessible(true); constructor.setAccessible(true); method.setAccessible(true); } }