HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException Unable to compile class for JSP
    org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java97)
    org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java342)
    org.apache.jasper.compiler.AntCompiler.generateClass(AntCompiler.java248)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java288)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java267)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java255)
    org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java556)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java296)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java295)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java245)
    javax.servlet.http.HttpServlet.service(HttpServlet.java802)
    org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java362)

root cause

Unable to find a javac compiler;
com.sun.tools.javac.Main is not on the classpath.
Perhaps JAVA_HOME does not point to the JDK
    org.apache.tools.ant.taskdefs.compilers.CompilerAdapterFactory.getCompiler(CompilerAdapterFactory.java106)
    org.apache.tools.ant.taskdefs.Javac.compile(Javac.java935)
    org.apache.tools.ant.taskdefs.Javac.execute(Javac.java764)
    org.apache.jasper.compiler.AntCompiler.generateClass(AntCompiler.java216)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java288)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java267)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java255)
    org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java556)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java296)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java295)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java245)
    javax.servlet.http.HttpServlet.service(HttpServlet.java802)
    org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java362)

note The full stack trace of the root cause is available in the Apache Tomcat5.5.7 logs.
Apache Tomcat5.5.7