Restarting Tomcat, log4j error

You can find hint, when you see the tomcat error.

log4j:WARN No appenders could be found for logger (org.apache.catalina.startup.Embedded).
log4j:WARN Please initialize the log4j system properly.
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:294)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:432)
Caused by: java.lang.NullPointerException
    at org.apache.catalina.startup.Catalina.await(Catalina.java:615)
    at org.apache.catalina.startup.Catalina.start(Catalina.java:575)
    ... 6 more

It means error occured in starting tomcat. so that you should look carefully at tomcat configuration files such as server.xml.

Wow!!! port string is not wrapped by double quotation("), 'port=6101' must be changed to 'port="6101"'.

<Server port="5101" shutdown="SHUTDOWN">
  <Service name="Catalina">
    <Connector port=6101 enableLookups="false" redirectPort="8443" protocol="AJP/1.3" URIEncoding="UTF-8" />
    <Engine name="Catalina" defaultHost="localhost" jvmRoute="hangame_hsec">
      <Host workDir="work/google_hsec" name="localhost" debug="0" appBase="webapps" unpackWARs="true" autoDeploy="true">
        <Context docBase="/home/www/work/project/google_hsec/web" path="">
          <Logger className="org.apache.catalina.logger.SystemOutLogger" verbosity="4" timestamp="true" />
        </Context>
      </Host>
    </Engine>
  </Service>
</Server>