To resolve the first problem
1. open "{jboss_home}\server\default\deploy\jbossweb-tomcat55.sar\META-INF\jboss-service.xml".
2.  <attribute name="Java2ClassLoadingCompliance">true</attribute>
      <attribute name="UseJBossWebLoader">true</attribute>

To resolve the second problem
1. open "{jboss_home}\server\default\deploy\jbossweb-tomcat55.sar\conf\web.xml".
2. locate at "<servlet>" entry, try to find "<servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>"
3. Add  2 init-params as following:
            <init-param>
               <param-name>compilerSourceVM</param-name>
               <param-value>1.5</param-value>
            </init-param>

            <init-param>
               <param-name>compilerTargetVM</param-name>
               <param-value>1.5</param-value>
            </init-param>   
4. If we want to use Log4j.properties in our own application, modify "{jboss_home}\server\default\conf\jboss_service.xml":
    <mbean code="org.jboss.logging.Log4jService" name="jboss.system:type=Log4jService,service=Logging">
         <attribute name="ConfigurationURL">resource:log4j.xml</attribute>
         <attribute name="CatchSystemOut">false</attribute>
         <attribute name="Log4jQuietMode">true</attribute>
    </mbean>