Struts Result interface is a public interface of package com.opensymphony.xwork2. It extends Serializable interface. All the known classes such as PlainTextResult, ServletRedirectResult, ServletActionRedirectResult, FreemarkerResult, StrutsResultSupport, VelocityResult, NullResult, XSLTResult, ActionChainResult, FreemarkerResult, ServletDispatcherResult, MockResult implements it.
It has a single method method execute(ActionInvocation invocation). It represents a generic interface for execution results for all actions.