應用場景：

專案架構:  Emmbed Jetty + Spring + JSP+Maven。

專案通過maven-shade-plugin外掛打為jar包，通過命令：“java -jar xxx.jar” 方式執行。

注意：伺服器端安裝JRE環境，而非JDK。如果安裝JDK則訪問正常！！！

Maven JSP配置：

<dependency>
     <groupId>org.eclipse.jetty</groupId>
     <artifactId>jetty-jsp</artifactId>
     <version>8.1.4.v20120524

訪問頁面，報錯：

HTTP ERROR 500

Problem accessing /. Reason:

    PWC6345: There is an error in invoking javac.  A full JDK (not just JRE) is required

Caused by:

org.apache.jasper.JasperException: PWC6345: There is an error in invoking javac.  A full JDK (not just JRE) is required
	at org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:92)
	at org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:378)
	at org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:119)
	at org.apache.jasper.compiler.Jsr199JavaCompiler.compile(Jsr199JavaCompiler.java:208)
	at org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:384)
	at org.apache.jasper.compiler.Compiler.compile(Compiler.java:453)
	at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:625)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:492)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:378)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:643)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:450)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:131)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:542)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1067)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:377)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:192)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1001)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:129)
	at org.eclipse.jetty.server.Dispatcher.forward(Dispatcher.java:271)
	at org.eclipse.jetty.server.Dispatcher.forward(Dispatcher.java:98)
	at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
	at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:262)
	at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1180)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:950)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:735)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:643)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:450)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:131)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1067)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:377)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:192)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1001)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:129)
	at org.eclipse.jetty.server.handler.HandlerList.handle(HandlerList.java:47)
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:149)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:111)
	at org.eclipse.jetty.server.Server.handle(Server.java:360)
	at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:454)
	at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:890)
	at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:944)
	at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:630)
	at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:230)
	at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:77)
	at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:622)
	at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:46)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:603)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:538)
	at java.lang.Thread.run(Unknown Source)

搜尋了半天，一直不明白是什麼原因，曾經想過在專案打包時對JSP進行預編譯是否能解決問題，沒有找到相應的方法。

後來想想應該是JSP依賴的問題，故將maven配置修改為：

<dependency>
    <groupId>org.mortbay.jetty</groupId>
    <artifactId>jsp-2.1-glassfish</artifactId>
    <version>9.1.02.B04.p0</version>
</dependency>
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>jstl</artifactId>
    <version>1.2</version>
</dependency>

在進行打包，放到伺服器端執行，不再報錯！

但是暫時還沒明白是什麼具體原因，先備註之。