"jackhexy" wrote : When I change nul to null,execute run.bat, | DOS prompt #Exception in thread "main" java.lang.NoClassDefFoundError: %JAVA_OPTS%#. | How to configure %JAVA_OPTS%? Doing these random changes is not going to lead us to a solution. Undo all the changes that you have done to your run.bat file, use the run.bat file which you downloaded from JBoss then try running it. When you run into that error again follow the instruction that i mentioned earlier (which are as follows) : "jaikiran" wrote : | Thats right. Its evident that the problem happens on this specific line. In the past week, there have been a couple of posts where similar issue was observed which resulted in the run.bat file terminating without any messages. The cause for that behaviour was turned out to be JAVA_HOME value not being properly set. In your case though the JAVA_HOME value and the output of %JAVA% -version look good. So that does not seem to be the issue. | | The second reason why this line might fail is related to 'findstr' not being in the PATH env variable (the link that i posted in my first reply http://wiki.jboss.org/wiki/Wiki.jsp?page=FindstrCommandNotFound ). Are you sure the 'findstr' is be on the PATH. You can find it under windows\system32 folder on your system. If you dont have it in the PATH then you will have to add it as follows(just an example): | | set PATH=%PATH%;C:\windows\system32 | | Once you have successfully ruled out these 2 probable causes, we will be able to move forward. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4104641#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...