What is tcnative.dll in Tomcat?

The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: C:\Program Files\Apache Software Foundation\Apache Tomcat 6.0.16\lib;

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:585)

at org.apache.catalina.core.AprLifecycleListener.init(AprLifecycleListener.java:135)

at org.apache.catalina.core.AprLifecycleListener.lifecycleEvent(AprLifecycleListener.java:80)

at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)

at org.apache.catalina.core.StandardServer.initialize(StandardServer.java:770)

at org.apache.catalina.startup.Catalina.load(Catalina.java:530)

at org.apache.catalina.startup.Catalina.load(Catalina.java:550)

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:585)

at org.apache.catalina.startup.Bootstrap.load(Bootstrap.java:260)

at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:412)

Caused by: java.lang.UnsatisfiedLinkError: no tcnative-1 in java.library.path, no libtcnative-1 in java.library.path(C:\Program Files\Apache Software Foundation\Apache Tomcat 6.0.16\lib;)

Cause:

You get this message when you start Tomcat. Tomcat is looking for a shared object call tcnative (dll or so depending on the platform). If it doesn't find it, it'll revert to java libs. Either way, this shouldn't affect your application. tcnative dll is needed to address scalability in Tomcat.

Solution:

1. Turn down debugging level for Tomcat or
2. Get tcnative from http://tomcat.apache.org/native-doc/ (windows users can download the binary) and place it in your library path.
3. Lib path is usually: C:\Program Files\Apache Software Foundation\Apache Tomcat 6.0.16\lib; for windows