upgarding grails 1.1.1 to 1.2.1 - grails

Question

I am trying to upgrade my grails project from grails 1.1.1 to grails 1.2.1.
when I am trying to run my application I am getting below error message:
I am using java 1.7._09 and GGTS 3.6.4.
This is my application.properties file:
when I am trying to add tomcat 1.2.1 in my application.properties file I am getting below error:
My GGTS is using default groovy compiler 2.3. Should I need to change the groovy complier?
I have searched in Google but I didn't understand:
search result from google
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite$PogoCachedMethodSiteNoUnwrapNoCoerce.invoke(PogoMetaMethodSite.java:266)
at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite.callCurrent(PogoMetaMethodSite.java:51)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallCurrent(CallSiteArray.java:44)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:143)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:155)
at gant.Gant.processTargets(Gant.groovy:480)
at org.codehaus.groovy.grails.cli.GrailsScriptRunner.callPluginOrGrailsScript(GrailsScriptRunner.java:485)
at org.codehaus.groovy.grails.cli.GrailsScriptRunner.executeCommand(GrailsScriptRunner.java:301)
at org.codehaus.groovy.grails.cli.GrailsScriptRunner.main(GrailsScriptRunner.java:115)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.codehaus.groovy.grails.cli.support.GrailsStarter.rootLoader(GrailsStarter.java:215)
at org.codehaus.groovy.grails.cli.support.GrailsStarter.main(GrailsStarter.java:240)
Caused by: java.lang.IllegalArgumentException: addChild: Child name 'grails-errorhandler' is not unique
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:781)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardContext.addChild(StandardContext.java:2128)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.apache.tomcat.util.IntrospectionUtils.callMethod1(IntrospectionUtils.java:925)
at org.apache.tomcat.util.digester.SetNextRule.end(SetNextRule.java:193)
at org.apache.tomcat.util.digester.Rule.end(Rule.java:229)
at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:1140)
... 438 more
startup.ContextConfig Occurred at line 7 column 422
startup.ContextConfig Marking this application unavailable due to previous error(s)
core.StandardContext Error getConfigured
core.StandardContext Context [/BASF_bdw] startup failed due to previous errors
Server running. Browse to http://localhost:8080/BASF_bdw
plugins.DefaultGrailsPluginManager Started to scan for plugin changes in every 5000ms.
I have found duplicate servlet name in .grails/***/resource/web.xml while running the run-app command in GGTS.
<servlet>
<servlet-name>grails-errorhandler</servlet-name>
<servlet-class>org.codehaus.groovy.grails.web.servlet.ErrorHandlingServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>grails-errorhandler</servlet-name>
<servlet-class>org.codehaus.groovy.grails.web.servlet.ErrorHandlingServlet</servlet-class>
</servlet>
may I know why it is generating duplicate servlet name and how to fix this ?

Answer 1

The blog says that you should search for every class that extends the class Exception or a subclass of it and convert it from a groovy to a java class. However, it looks like it is not your code, but the internal Grails code that throws the exception.
Looking at your previous questions, it seems your final goal is to make your war runnable in a Java 7 Environment.
You should stick to java 6 on your upgrade-journey until you hit a Grails version that just runs on Java 7.
After every successful upgrade, compile your project with Java 6 and try to run it in a servlet container that runs on Java 7. Perhaps you'r lucky and it just works.
I'm pretty sure that this will not the last problem.
I don't know how many lines of code your project has, perhaps it's an option to reimplement the whole project in grails 3.