Error 500--Internal Server Error

java.lang.ArithmeticException: / by zero
	at inet.controller.GioiThieuController.handleRequestInternal(GioiThieuController.java:30)
	at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:154)
	at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:50)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:945)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:876)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:645)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:750)
	at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:295)
	at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:260)
	at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:137)
	at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:353)
	at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:250)
	at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:649)
	at weblogic.servlet.internal.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:290)
	at org.tuckey.web.filters.urlrewrite.NormalRewrittenUrl.doRewrite(NormalRewrittenUrl.java:213)
	at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:171)
	at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:145)
	at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:92)
	at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:394)
	at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:82)
	at inet.trimfilter.ReplaceHTMLFilter.doFilter(ReplaceHTMLFilter.java:42)
	at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:82)
	at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3866)
	at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3829)
	at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:344)
	at weblogic.security.service.SecurityManager.runAsForUserCode(SecurityManager.java:197)
	at weblogic.servlet.provider.WlsSecurityProvider.runAsForUserCode(WlsSecurityProvider.java:203)
	at weblogic.servlet.provider.WlsSubjectHandle.run(WlsSubjectHandle.java:71)
	at weblogic.servlet.internal.WebAppServletContext.processSecuredExecute(WebAppServletContext.java:2502)
	at weblogic.servlet.internal.WebAppServletContext.doSecuredExecute(WebAppServletContext.java:2351)
	at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2326)
	at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2304)
	at weblogic.servlet.internal.ServletRequestImpl.runInternal(ServletRequestImpl.java:1779)
	at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1733)
	at weblogic.servlet.provider.ContainerSupportProviderImpl$WlsRequestExecutor.run(ContainerSupportProviderImpl.java:272)
	at weblogic.invocation.ComponentInvocationContextManager._runAs(ComponentInvocationContextManager.java:352)
	at weblogic.invocation.ComponentInvocationContextManager.runAs(ComponentInvocationContextManager.java:337)
	at weblogic.work.LivePartitionUtility.doRunWorkUnderContext(LivePartitionUtility.java:57)
	at weblogic.work.PartitionUtility.runWorkUnderContext(PartitionUtility.java:41)
	at weblogic.work.SelfTuningWorkManagerImpl.runWorkUnderContext(SelfTuningWorkManagerImpl.java:651)
	at weblogic.work.ExecuteThread.execute(ExecuteThread.java:420)
	at weblogic.work.ExecuteThread.run(ExecuteThread.java:360)