在实现的方法上获取java.lang.AbstractMethodError
正如标题所述，我在一个由我的类明确实现的方法上得到了一个java.lang.AbstractMethodError 。 完整的错误消息是：
java.lang.AbstractMethodError: htmlexport.HTMLExport.getParameterFormDescriptor()Ljava/util/List;
我有一个接口，定义方法如下：
List getParameterFormDescriptor();
正如我所说，这个方法是由实现类实现的。
该接口包含在我本地Maven存储库中的jar中。 我已经尝试过mvn clean和mvn install并碰撞版本号，但这并没有解决问题。
实现类在另一个jar文件中，我使用ANT脚本创建。 然后通过主应用程序中的ClassLoader加载该文件。
为什么我得到这个错误的任何线索？ 界面定义的所有其他方法都有效。
这是代码
我有一个Wicket WebPage ，我调用这个方法：
public class AddJobPage extends BasePage { public AddJobPage(final PageParameters params) { super(params); final Workable w = WorkableManager.getInstance().findWorkableByName(params.get("workableName").toString()); w.getParameterFormDescriptor(); } }
WorkableManager内部使用URLClassLoader加载包含实现类的jar文件。 这工作正常，我得到了所需类的实例。
定义方法的接口是：
public interface Workable { List getParameterFormDescriptor(); }
实现类看起来像这样（ Module extends Workable ）：
public class HTMLExport implements Module { @Override public final List getParameterFormDescriptor() { final List form = new ArrayList(); form.add(new ParamFormElement(ParamFormElement.Type.TEXT, "Bitte eingeben:", "test")); return form; } }
该接口位于一个单独的项目中，并在我的本地Maven存储库中组装为一个jar文件。 HTMLExport类也在不同的项目中，并使用Ant进行编译和组装。 生成的jar文件位于我的主应用程序旁边的文件夹中，正如我所说的加载类工作。 主应用程序是一个Maven项目，并将接口添加为依赖项。 在Eclipse中，我没有任何错误或警告。
堆栈跟踪如下：
Root cause: java.lang.AbstractMethodError: htmlexport.HTMLExport.getParameterFormDescriptor()Ljava/util/List; at web.pages.AddJobPage.(AddJobPage.java:30) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at java.lang.reflect.Constructor.newInstance(Constructor.java:525) at org.apache.wicket.session.DefaultPageFactory.newPage(DefaultPageFactory.java:171) at org.apache.wicket.session.DefaultPageFactory.newPage(DefaultPageFactory.java:99) at org.apache.wicket.DefaultMapperContext.newPageInstance(DefaultMapperContext.java:137) at org.apache.wicket.core.request.handler.PageProvider.resolvePageInstance(PageProvider.java:268) at org.apache.wicket.core.request.handler.PageProvider.getPageInstance(PageProvider.java:166) at org.apache.wicket.request.handler.render.PageRenderer.getPage(PageRenderer.java:78) at org.apache.wicket.request.handler.render.WebPageRenderer.isPageStateless(WebPageRenderer.java:300) at org.apache.wicket.request.handler.render.WebPageRenderer.shouldRenderPageAndWriteResponse(WebPageRenderer.java:342) at org.apache.wicket.request.handler.render.WebPageRenderer.respond(WebPageRenderer.java:203) at org.apache.wicket.core.request.handler.RenderPageRequestHandler.respond(RenderPageRequestHandler.java:175) at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:837) at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64) at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:265) at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:222) at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:293) at org.apache.wicket.protocol.http.WicketFilter.processRequestCycle(WicketFilter.java:261) at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:203) at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:284) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1631) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:549) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:568) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:221) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1111) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:478) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:183) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1045) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:199) at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:109) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97) at org.eclipse.jetty.server.Server.handle(Server.java:462) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:279) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:232) at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:534) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:607) at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:536) at java.lang.Thread.run(Thread.java:722) Complete stack: org.apache.wicket.WicketRuntimeException: Can't instantiate page using constructor 'public web.pages.AddJobPage(org.apache.wicket.request.mapper.parameter.PageParameters)' and argument 'workableName=[HTML Export]'. An exception has been thrown during construction! at org.apache.wicket.session.DefaultPageFactory.newPage(DefaultPageFactory.java:194) at org.apache.wicket.session.DefaultPageFactory.newPage(DefaultPageFactory.java:99) at org.apache.wicket.DefaultMapperContext.newPageInstance(DefaultMapperContext.java:137) at org.apache.wicket.core.request.handler.PageProvider.resolvePageInstance(PageProvider.java:268) at org.apache.wicket.core.request.handler.PageProvider.getPageInstance(PageProvider.java:166) at org.apache.wicket.request.handler.render.PageRenderer.getPage(PageRenderer.java:78) at org.apache.wicket.request.handler.render.WebPageRenderer.isPageStateless(WebPageRenderer.java:300) at org.apache.wicket.request.handler.render.WebPageRenderer.shouldRenderPageAndWriteResponse(WebPageRenderer.java:342) at org.apache.wicket.request.handler.render.WebPageRenderer.respond(WebPageRenderer.java:203) at org.apache.wicket.core.request.handler.RenderPageRequestHandler.respond(RenderPageRequestHandler.java:175) at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:837) at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64) at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:265) at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:222) at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:293) at org.apache.wicket.protocol.http.WicketFilter.processRequestCycle(WicketFilter.java:261) java.lang.reflect.InvocationTargetException at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at java.lang.reflect.Constructor.newInstance(Constructor.java:525) at org.apache.wicket.session.DefaultPageFactory.newPage(DefaultPageFactory.java:171) at org.apache.wicket.session.DefaultPageFactory.newPage(DefaultPageFactory.java:99) at org.apache.wicket.DefaultMapperContext.newPageInstance(DefaultMapperContext.java:137) at org.apache.wicket.core.request.handler.PageProvider.resolvePageInstance(PageProvider.java:268) at org.apache.wicket.core.request.handler.PageProvider.getPageInstance(PageProvider.java:166) at org.apache.wicket.request.handler.render.PageRenderer.getPage(PageRenderer.java:78) at org.apache.wicket.request.handler.render.WebPageRenderer.isPageStateless(WebPageRenderer.java:300) at org.apache.wicket.request.handler.render.WebPageRenderer.shouldRenderPageAndWriteResponse(WebPageRenderer.java:342) at org.apache.wicket.request.handler.render.WebPageRenderer.respond(WebPageRenderer.java:203) at org.apache.wicket.core.request.handler.RenderPageRequestHandler.respond(RenderPageRequestHandler.java:175) at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:837) at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64) at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:265) at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:222) at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:293) at org.apache.wicket.protocol.http.WicketFilter.processRequestCycle(WicketFilter.java:261)
确保您的类路径中有最新的jar文件而不是旧版本。 如果您在运行时看到这种情况，则会由于不兼容的二进制文件而发生这种情况
来自Oracle java站点
应用程序尝试调用抽象方法时抛出。 通常，编译器会捕获此错误; 如果自上次编译当前正在执行的方法以来某些类的定义发生了不兼容的更改，则此错误只能在运行时发生 。
链接到类AbstractMethodError
还可以尝试-U标志强制更新依赖项。
mvn clean install -U
如果你的实现类的jar不在类路径中或不确定
尝试下面的代码
YourInterfaceName obj = (YourInterfaceName)Class.forName ("yourPackageName.YourInterfaceImplClassName").newInstance();
问题是实现类没有正确编译，Ant脚本没有将正确的类复制到jar文件中。 我将它转换为maven项目，现在可以找到该方法。