Make web application start up faster

To make web application start up faster in Tomcat, you may consider the following tuning:

1. Add metadata-complete="true" as an attribute in <web-app> tag
2. Add <absolute-ordering/> inside <web-app> </web-app>

Setting Tomcat JVM in service mode

Running Tomcat (Service mode) with default Java Virtual Machine (JVM) could cause some strange problem sometimes. It's because your own development may depends on a particular VM (e.g. the HotSpot VM). In this case, you will need to specify the JVM instead of using the default one.

To do this, run the tomcat7w.exe in TOMCAT_HOME\bin\, and select the the Java tab. You will find the Java Virtual Machine option as shown below:

JSP too large for Tomcat

A long JSP just worked in Tomcat 6.0.29. Somehow when we put it in 6.0.35, it got error "Unresolved compilation problem".

It seems that the new Jasper (/lib/ecj-3.7.jar) just not work for large JSP. One of the solution will be using the Jasper from 6.0.29 (/lib/jasper-jdt.jar) instead.

Or.. keep using the 6.0.29 for some while...

Solution for java.io.NotSerializableException error when Tomcat reloads

To solve the Tomcat restart error, add <Manager> setting in <Context> section:

<Manager className="org.apache.catalina.session.PersistentManager" 
         saveOnRestart="false">
    <Store className="org.apache.catalina.session.FileStore"/>
</Manager>


References:

• http://blog.csdn.net/forandever/article/details/4553447
• http://stackoverflow.com/questions/4232222/cannot-resolve-this-error-notserializableexception

Determine user in Tomcat

To determine user authentication info in Tomcat, we can use the following:

getRemoteUser()
isUserInRole(String role)

Both methods are under javax.servlet.http.HttpServletRequest.

Some options for Tomcat 6

Not much options found, but I drop down the useful ones for reference. Note that those options should be assigned to the CATALINA_OPTS. Actually, you may put them in catalina.bat.

• Startup memory size
  -Xms256m

• Maximum memory size
  -Xmx256m

• Garbage collection path
  -Xloggc:/gc.log

• Disable DNS caching
  -Dsun.net.inetaddr.ttl=0

• Skip quote escape checking (If you have tag like this <mytags:tag value="<%= "hi!" %>" /> , which is validate in Tomcat 5 before. In Tomcat 6, you may need to turn on the following option to prevent running into error. Ref: http://www.andowson.com/posts/list/346.page)
  -Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPE=false

• Turn on JMX remote
  -Dcom.sun.management.jmxremote
  -Dcom.sun.management.jmxremote.port=9004
  -Dcom.sun.management.jmxremote.authenticate=false
  -Dcom.sun.management.jmxremote.ssl=false

• Set default Tomcat language / locale to English
  -Duser.language=en

Debug mode in Eclipse and Tomcat

For Tomcat:
  set JPDA_ADDRESS=8000
  set JPDA_TRANSPORT=dt_socket
  catalina.bat jpda start

For Eclipse:
  Set Connection Port (8000) and Connection Host (localhost) in "Run > Debug Configurations"
  Configuration Type: "Remote Java Application"
  Set connection port to "8000"
  Set connection host to "localhost"