It means exactly what it says: "The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path"
The library referred to is bundled into an OS specific dll (tcnative-1.dll) loaded via JNI. It allows tomcat to use OS functionalities not provided in the Java Runtime (such as sendfile, epoll, OpenSSL, system status, etc.). Tomcat will run just fine without it, but for some use cases, it will be faster with the native libraries.
If you really want it, download the tcnative-1.dll
(or libtcnative.so
for Linux) and put it in the bin folder, and add a system property to the launch configuration of the tomcat server in eclipse.
-Djava.library.path=c:\dev\tomcat\bin