class not found exception using backward compatibility library in android
<p>I have developed project in android3.1 and i am trying to run in android2.1 emulator . I have added android-support-v4.jar and specified     
 in manifest file .can anybody tell what is problem how to solve?</p>

<pre><code>02-03 15:06:08.623: E/AndroidRuntime(223): Uncaught handler: thread main exiting due to uncaught exception
02-03 15:06:08.641: E/AndroidRuntime(223): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test.fragment/com.test.fragment.FragmentTestWebActivity}: android.view.InflateException: Binary XML file line #13: Error inflating class fragment
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.app.ActivityThread.access$2200(ActivityThread.java:119)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.os.Handler.dispatchMessage(Handler.java:99)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.os.Looper.loop(Looper.java:123)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.app.ActivityThread.main(ActivityThread.java:4363)
02-03 15:06:08.641: E/AndroidRuntime(223):  at java.lang.reflect.Method.invokeNative(Native Method)
02-03 15:06:08.641: E/AndroidRuntime(223):  at java.lang.reflect.Method.invoke(Method.java:521)
02-03 15:06:08.641: E/AndroidRuntime(223):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
02-03 15:06:08.641: E/AndroidRuntime(223):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
02-03 15:06:08.641: E/AndroidRuntime(223):  at dalvik.system.NativeStart.main(Native Method)
02-03 15:06:08.641: E/AndroidRuntime(223): Caused by: android.view.InflateException: Binary XML file line #13: Error inflating class fragment
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:576)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.view.LayoutInflater.rInflate(LayoutInflater.java:618)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.view.LayoutInflater.inflate(LayoutInflater.java:407)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.view.LayoutInflater.inflate(LayoutInflater.java:320)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.view.LayoutInflater.inflate(LayoutInflater.java:276)
02-03 15:06:08.641: E/AndroidRuntime(223):  at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:198)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.app.Activity.setContentView(Activity.java:1622)
02-03 15:06:08.641: E/AndroidRuntime(223):  at com.test.fragment.FragmentTestWebActivity.onCreate(FragmentTestWebActivity.java:13)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
02-03 15:06:08.641: E/AndroidRuntime(223):  ... 11 more
02-03 15:06:08.641: E/AndroidRuntime(223): Caused by: java.lang.ClassNotFoundException: android.view.fragment in loader dalvik.system.PathClassLoader@48079860
02-03 15:06:08.641: E/AndroidRuntime(223):  at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
02-03 15:06:08.641: E/AndroidRuntime(223):  at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
02-03 15:06:08.641: E/AndroidRuntime(223):  at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.view.LayoutInflater.createView(LayoutInflater.java:466)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.view.LayoutInflater.onCreateView(LayoutInflater.java:544)
02-03 15:06:08.641: E/AndroidRuntime(223):  at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:66)
02-03 15:06:08.641: E/AndroidRuntime(223):  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:563)
02-03 15:06:08.641: E/AndroidRuntime(223):  ... 20 more
</code></pre>

<p>thanks</p>
