følgende fejl får jeg fra tomcat

Cannot use classic compiler , as it is not available.
A common solution is to set the environment variable JAVA_HOME to your jdk directory.
It is currently set to "D:\IBM\WebSphereStudio\eclipse\jre"
    at org.apache.tools.ant.taskdefs.compilers.Javac12.execute(Javac12.java:69)
    at org.apache.tools.ant.taskdefs.Javac.compile(Javac.java:997)
    at org.apache.tools.ant.taskdefs.Javac.execute(Javac.java:820)
    at org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:310)
    at org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)
    at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:427)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:142)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:240)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:187)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:199)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:145)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
    at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:955)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:139)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
    at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:955)
    at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2460)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:133)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
    at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:119)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:594)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:594)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
    at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:955)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:127)
    at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
    at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:955)
    at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:157)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:874)
    at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
    at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
    at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
    at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:685)
    at java.lang.Thread.run(Thread.javavad :512)

hvad skal der gøres