UnsatisfiedLinkError While Calling Native Method from OSGi Bundle

I have created one OSGi plugin (Bundle) using eclipse File-->New-->Other-->Plug-in Project called plugin 1. I want to use a native .so library in this plugin. I have added libtest_app_wrap1.so at the root of my plugin project.

my project structure looks like below

And here is the manifest file

Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: JniTest
Bundle-SymbolicName: JniTest
Bundle-Version: 1.0.0.qualifier
Bundle-Activator: jnitest.Activator
Bundle-RequiredExecutionEnvironment: JavaSE-1.8
Import-Package: org.osgi.framework;version="1.3.0"
Bundle-NativeCode: libtest_app_wrap1.so; osname=linux; processor=amd64

And this is the code of my Activator class

    package jnitest;

import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;

public class Activator implements BundleActivator {

    public Activator() {
        System.loadLibrary("test_app_wrap1");
        System.out.println("Library Loaded Successfully.......");
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.osgi.framework.BundleActivator#start(org.osgi.framework.BundleContext)
     */
    public void start(BundleContext context) throws Exception {
        try {
            test_app.foo();

        } catch (Throwable tr) {
            tr.printStackTrace();

        }
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.osgi.framework.BundleActivator#stop(org.osgi.framework.BundleContext)
     */
    public void stop(BundleContext context) throws Exception {
        System.out.println("Goodbye World!!");
    }

}

I create jar file from plugin project using eclipse export feature. output jar file contains .so library.

I don't get any exception or error when I call the System.loadLibrary("test_app_wrap1");, but when I call the method test_app.foo(); it gives me UnsatisfiedLinkError. test_app.foo() is a jni method which is defined in .so.

I am not getting any clue to resolve this error. Please help to get it resolve.

[Edit: Output bundle content]

Here is the content of the output jar