Apache Tomcat 6 starting problem

When I start my Tomcat 6.0 in netbeans I get such exceptions(3 times) in tomcat log:

SEVERE: Exception starting filter HTTPMonitorFilter
java.lang.ClassNotFoundException: org.netbeans.modules.web.monitor.server.MonitorFilter
        at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1387)
        at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1233)
        at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:249)
        at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:3开发者_Python百科97)
        at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:108)
        at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3800)
        at org.apache.catalina.core.StandardContext.start(StandardContext.java:4450)
        at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1173)
        at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1271)
        at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:296)
        at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
        at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1337)
        at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601)
        at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
        at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590)
        at java.lang.Thread.run(Thread.java:662)

Also netbeans is showing that tomcat is starting and I can't stop it(stop menu is inactive). After 2 or 3 minutes it shows an error that can't to start and shutdowns. But during this process and after it I can browse to localhost:8080 (I've set 8080 to server port in tomcat properties in netbeans) How can I fix this problem?

edit: I have reinstalled Apache tomcat and add it to netbeans. Now when I start the server it doesn't throw any exceptions, but after 2-3 minutes gives me the message: Starting of Tomcat failed Any ideas?

solved issue: if to set tomcat's server port to 8084 than it works fine! The problem was that netbeans "don't want" to run tomcat server on 8080 port(it is not associated with that some program is running on 8080 port, beacuse netstat -a command don't show any record with 8080 port). So I think it is a feauture/bug of Netbeans:)

What worked for me was:

Remove all the libraries that are in the folder "WebContent\WEB-INF\lib" and add all libraries again.

Additionally in the "Servers" window, select "Tomcat v8.0" then right click and select "Clean..." and "Clean Tomcat Work Directory" options.

:)