java - How to stub an exception multiple times in Mockito -

i want stub method call 40 times exception , real object. far can see, mockito 1.10.8's thenthrow() method accepts n number of throwables:

ongoingstubbing<t> thenthrow(throwable... throwables); 

therefore, thought following.

@runwith(mockitojunitrunner.class) public class myobjecttest {     @mock(answer = answers.returns_mocks)     private mama mama;      @mock(answer = answers.returns_deep_stubs)     private papa papa;      private myobject _instance;      @test     public void test()     {         _instance = new myobject(papa, mama);          throwable[] exceptions = new throwable[41];          arrays.fill(exceptions, 0, 40, new connectionexception("exception message"));          when(papa.getmapper().map(anystring())).thenthrow(exceptions).thenreturn(new mymap());          verify(papa, times(41)).getmapper().map(anystring());     } } 

however, when run test following.

org.mockito.exceptions.base.mockitoexception: cannot stub null throwable! @ myobjecttest.test(myobjecttest.java:105)

myobjecttest.java:105 line stubbing takes place.

why error?

you exception because have throwable[] 41 elements, fill 40 of them actual connectionexception value. last 1 null.

thenthrow not accept throwing null (which cause nullpointerexception thrown instead).

your array should contain 40 elements

throwable[] exceptions = new throwable[40];