The JRE Class White List A Java App Engine application's access to the classes in the Java standard library (the Java Runtime Environment, or JRE) is limited to the following classes: java.beans.AppletInitializer java.beans.BeanDescriptor java.beans.BeanInfo java.beans.Beans java.beans.ConstructorProperties java.beans.Customizer java.beans.DefaultPersistenceDelegate java.beans.DesignMode java.bean