NativeResourceUnloadWebListener fails when JNA is not on the class path.

[mrotteveel]

The NativeResourceUnloadWebListener fails when JNA is not on the classpath as reported on https://groups.google.com/g/firebird-java/c/aRrtXQGR5Dg, as it will fail to find com.sun.jna.Library when loading FbClientLibrary. The lookup of the class loader should be isolated, or any errors when loading it should be swallowed.

Exception sending context initialized event to listener instance of class [org.firebirdsql.gds.ng.jna.NativeResourceUnloadWebListener]
java.lang.NoClassDefFoundError: com/sun/jna/Library
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:756)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2478)
        at org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:870)
        at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1371)
        at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1215)
        at org.firebirdsql.gds.ng.jna.NativeResourceUnloadWebListener.jaybirdLoadedInContext(NativeResourceUnloadWebListener.java:54)
        at org.firebirdsql.gds.ng.jna.NativeResourceUnloadWebListener.contextInitialized(NativeResourceUnloadWebListener.java:40)

Workarounds:

• Set system property org.firebirdsql.nativeResourceShutdownDisable to true
• Add jna-5.5.0 (or higher) to the class path

[mrotteveel]

Fixed by checking class loader of FbClientDatabaseFactory instead.