how to solve Test run failed: Instrumentation run failed due to 'Native crash' in robotium -

i trying junit test facing following issue.

when select android junit test right clicking on project shows following message

test run failed: instrumentation run failed due 'native crash'

and when right click on testapk.java , select android junit test, shows

test run failed: instrumentation run failed due java.lang.classnotfoundexception

two cases occurs

here source code.

@suppresswarnings("unchecked") public class testapk extends activityinstrumentationtestcase2 {        private static final string launcher_activity_full_classname = "com.nhn.android.ndrive";       private static class launcheractivityclass;       static {            try {               launcheractivityclass = class                 .forname(launcher_activity_full_classname);           } catch (classnotfoundexception e) {             throw new runtimeexception(e);           }       }        public testapk() throws classnotfoundexception {           super(launcheractivityclass);       }        private solo solo;        @override       protected void setup() throws exception {          super.setup();          solo = new solo(getinstrumentation(), getactivity());       }        public void testdisplayblackbox() {          //enter integer/decimal value first editfield, writing  10          solo.clickonwebelement(by.id("com.nhn.android.ndrive:id/actionbar_photo_left_button"));          solo.clickonwebelement(by.id("com.nhn.android.ndrive:id/gnb_group_layout"));          //enter integer/decimal value first editfield, writing  20           solo.clickonwebelement(by.id("com.nhn.android.ndrive:id/actionbar_open_drawer_button"));          //click on multiply button          solo.clickonbutton("com.nhn.android.ndrive:id/base_menu_task_open_button");          //verify resultant of 10 x 20         //asserttrue(solo.searchtext("200"));        }         @override        public void teardown() throws exception {             solo.finishopenedactivities();        }  } 

but package name not wrong.

how solve problem?