title: Exception while testing my application on device by connecting divce with usb
body: <p>It gives exception whenever app is installed and launched . And somtime it suddenly through <strong>exception</strong> and my gets <strong>crashed</strong></p>
  
  <blockquote>
    <p>java.lang.RuntimeException: Unable to instantiate application com.android.tools.fd.runtime.BootstrapApplication: java.lang.NullPointerException
                                                                                  at android.app.LoadedApk.makeApplication(LoadedApk.java:501)
                                                                                  at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4255)
                                                                                  at android.app.ActivityThread.access$1400(ActivityThread.java:140)
                                                                                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1297)
                                                                                  at android.os.Handler.dispatchMessage(Handler.java:99)
                                                                                  at android.os.Looper.loop(Looper.java:174)
                                                                                  at android.app.ActivityThread.main(ActivityThread.java:4952)
                                                                                  at java.lang.reflect.Method.invokeNative(Native Method)
                                                                                  at java.lang.reflect.Method.invoke(Method.java:511)
                                                                                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
                                                                                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
                                                                                  at dalvik.system.NativeStart.main(Native Method)
                                                                               Caused by: java.lang.NullPointerException
                                                                                  at android.app.LoadedApk.initializeJavaContextClassLoader(LoadedApk.java:377)
                                                                                  at android.app.LoadedApk.getClassLoader(LoadedApk.java:320)
                                                                                  at android.app.LoadedApk.makeApplication(LoadedApk.java:493)
                                                                                  at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4255) 
                                                                                  at android.app.ActivityThread.access$1400(ActivityThread.java:140) 
                                                                                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1297) 
                                                                                  at android.os.Handler.dispatchMessage(Handler.java:99) 
                                                                                  at android.os.Looper.loop(Looper.java:174) 
                                                                                  at android.app.ActivityThread.main(ActivityThread.java:4952) 
                                                                                  at java.lang.reflect.Method.invokeNative(Native Method) 
                                                                                  at java.lang.reflect.Method.invoke(Method.java:511) 
                                                                                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027) 
                                                                                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794) 
                                                                                  at dalvik.system.NativeStart.main(Native Method) </p>
  </blockquote>
  
  <p>Why this exception is thrown ? and how to handle it .I am new to android world </p>