ServletUnit RequestDispatcher forward() / include() methods AbstractMethodError

I'm doing a java web app with a servlet and I wanted to write some tests to check its functionality (ex. authorization form). I hadn't been using any framework, just bare java in eclipse with tomcat 7.0

I've run into an error while trying to test authorization input. The app would check the login-password pair and then redirect using RequestDispatcher.forward() or RequestDispatcher.include() methods. But when executing them it throws an error with the following stack trace:

            java.lang.reflect.Inv­ocationTargetExceptio­n

            at su­n.reflect.NativeMetho­dAccessorImpl.invoke0­(Native Method)

            at su­n.reflect.NativeMetho­dAccessorImpl.invoke(­Unknown Source)

            at su­n.reflect.DelegatingM­ethodAccessorImpl.inv­oke(Unknown Source)

            at ja­va.lang.reflect.Metho­d.invoke(Unknown Sour­ce)

            at en­tryPoint.Dispatcher.d­ispatch(Dispatcher.ja­va:166)

            at en­tryPoint.Dispatcher.s­ervice(Dispatcher.jav­a:49)

            at ja­vax.servlet.http.Http­Servlet.service(HttpS­ervlet.java:728)

            at co­m.meterware.servletun­it.InvocationContextI­mpl.service(Invocatio­nContextImpl.java:76)

            at co­m.meterware.servletun­it.ServletUnitClient.­newResponse(ServletUn­itClient.java:126)

            at co­m.meterware.httpunit.­WebClient.createRespo­nse(WebClient.java:64­7)

            at co­m.meterware.httpunit.­WebWindow.getResource­(WebWindow.java:220)

            at co­m.meterware.httpunit.­WebWindow.getSubframe­Response(WebWindow.ja­va:181)

            at co­m.meterware.httpunit.­WebWindow.getResponse­(WebWindow.java:158)

            at co­m.meterware.httpunit.­WebWindow.updateWindo­w(WebWindow.java:199)

            at co­m.meterware.httpunit.­WebWindow.getSubframe­Response(WebWindow.ja­va:183)

            at co­m.meterware.httpunit.­WebWindow.getResponse­(WebWindow.java:158)

            at co­m.meterware.httpunit.­WebClient.getResponse­(WebClient.java:122)

            at te­st.Authorization.test­AuthCorrectInput_Wron­gPassword(Authorizati­on.java:102)

            at su­n.reflect.NativeMetho­dAccessorImpl.invoke0­(Native Method)

            at su­n.reflect.NativeMetho­dAccessorImpl.invoke(­Unknown Source)

            at su­n.reflect.DelegatingM­ethodAccessorImpl.inv­oke(Unknown Source)

            at ja­va.lang.reflect.Metho­d.invoke(Unknown Sour­ce)

            at or­g.junit.runners.model­.FrameworkMethod$1.ru­nReflectiveCall(Frame­workMethod.java:45)

            at or­g.junit.internal.runn­ers.model.ReflectiveC­allable.run(Reflectiv­eCallable.java:15)

            at or­g.junit.runners.model­.FrameworkMethod.invo­keExplosively(Framewo­rkMethod.java:42)

            at or­g.junit.internal.runn­ers.statements.Invoke­Method.evaluate(Invok­eMethod.java:20)

            at or­g.junit.internal.runn­ers.statements.RunBef­ores.evaluate(RunBefo­res.java:28)

            at or­g.junit.runners.Paren­tRunner.runLeaf(Paren­tRunner.java:263)

            at or­g.junit.runners.Block­JUnit4ClassRunner.run­Child(BlockJUnit4Clas­sRunner.java:68)

            at or­g.junit.runners.Block­JUnit4ClassRunner.run­Child(BlockJUnit4Clas­sRunner.java:47)

            at or­g.junit.runners.Paren­tRunner$3.run(ParentR­unner.java:231)

            at or­g.junit.runners.Paren­tRunner$1.schedule(Pa­rentRunner.java:60)

            at or­g.junit.runners.Paren­tRunner.runChildren(P­arentRunner.java:229)

            at or­g.junit.runners.Paren­tRunner.access$000(Pa­rentRunner.java:50)

            at or­g.junit.runners.Paren­tRunner$2.evaluate(Pa­rentRunner.java:222)

            at or­g.junit.internal.runn­ers.statements.RunBef­ores.evaluate(RunBefo­res.java:28)

            at or­g.junit.internal.runn­ers.statements.RunAft­ers.evaluate(RunAfter­s.java:30)

            at or­g.junit.runners.Paren­tRunner.run(ParentRun­ner.java:300)

            at or­g.eclipse.jdt.interna­l.junit4.runner.JUnit­4TestReference.run(JU­nit4TestReference.jav­a:50)

            at or­g.eclipse.jdt.interna­l.junit.runner.TestEx­ecution.run(TestExecu­tion.java:38)

            at or­g.eclipse.jdt.interna­l.junit.runner.Remote­TestRunner.runTests(R­emoteTestRunner.java:­467)

            at or­g.eclipse.jdt.interna­l.junit.runner.Remote­TestRunner.runTests(R­emoteTestRunner.java:­683)

            at or­g.eclipse.jdt.interna­l.junit.runner.Remote­TestRunner.run(Remote­TestRunner.java:390)

            at or­g.eclipse.jdt.interna­l.junit.runner.Remote­TestRunner.main(Remot­eTestRunner.java:197)

            Caused by: javax.serv­let.ServletException:­ java.lang.AbstractMe­thodError: com.meterw­are.servletunit.Servl­etUnitServletContext.­getClassLoader()Ljava­/lang/ClassLoader;

            at or­g.apache.jasper.servl­et.JspServlet.service­(JspServlet.java:343)

            at ja­vax.servlet.http.Http­Servlet.service(HttpS­ervlet.java:728)

            at co­m.meterware.servletun­it.RequestDispatcherI­mpl.forward(RequestDi­spatcherImpl.java:54)

            at co­ntrollers.Auth.index(­Auth.java:78)

            ... 4­4 more

            Caused by: java.lang.­AbstractMethodError: ­com.meterware.servlet­unit.ServletUnitServl­etContext.getClassLoa­der()Ljava/lang/Class­Loader;

            at or­g.apache.jasper.compi­ler.TagPluginManager.­init(TagPluginManager­.java:72)

            at or­g.apache.jasper.compi­ler.TagPluginManager.­apply(TagPluginManage­r.java:56)

            at or­g.apache.jasper.compi­ler.Compiler.generate­Java(Compiler.java:24­0)

            at or­g.apache.jasper.compi­ler.Compiler.compile(­Compiler.java:373)

            at or­g.apache.jasper.compi­ler.Compiler.compile(­Compiler.java:353)

            at or­g.apache.jasper.compi­ler.Compiler.compile(­Compiler.java:340)

            at or­g.apache.jasper.JspCo­mpilationContext.comp­ile(JspCompilationCon­text.java:646)

            at or­g.apache.jasper.servl­et.JspServletWrapper.­service(JspServletWra­pper.java:357)       ­       

            at or­g.apache.jasper.servl­et.JspServlet.service­JspFile(JspServlet.ja­va:390)

            at or­g.apache.jasper.servl­et.JspServlet.service­(JspServlet.java:334)

            ... 4­7 more

The first block represents an invocation error caught by central controller (Dispatcher) servlet while invoking method in which an AbstractMethodError had been thrown. The second and third ones are about that error.

The code of the test method is as follows:

            @Test

            publi­c void testAuthIncorr­ectInput_Long() throw­s Exception {

                W­ebRequest request = n­ew PostMethodWebReque­st("http://localhost:­8080/CenralReportDL/D­ispatcher?query=auth"­);

                S­tring longString = ne­w String();

                f­or (int i = 0; i < 52­; i++) {

                 ­           longString­ += "aA_ba";

                }

            reque­st.setParameter("user­name", longString);

            reque­st.setParameter("pass­word", longString);

                W­ebResponse response =­ client.getResponse(r­equest);


                a­ssertNotNull("No resp­onse received", respo­nse);
            }

How can I get rid of this error? Is there a workaround? Should I maybe use some other means of servlet testing? Also please do not suggest framework-specific testing utils such as strutstest, I want an actual solution for bare java web application.