android - Error after implementing StartApp Sdk -

i have implemented startapp sdk serve add in application giving error below. error showing in crash report. please remove error , avoid crash

please see crash report below

exception java.lang.nullpointerexception: attempt invoke interface methodjava.util.iterator java.util.list.iterator()' on null object reference com.startapp.android.publish.j.c.a () com.startapp.android.publish.j.c.a () com.startapp.android.publish.g.c.a () com.startapp.android.publish.g.d.d () com.startapp.android.publish.g.d$1.run () java.lang.thread.run (thread.java:818) 

here java file

package sujaynambiar.textilecalculation;  import android.app.dialog; import android.content.context; import android.os.bundle; import android.support.v7.app.appcompatactivity; import android.view.view; import android.view.window; import android.widget.arrayadapter; import android.widget.button; import android.widget.edittext; import android.widget.imageview; import android.widget.spinner; import android.widget.textview; import android.widget.toast;  import com.startapp.android.publish.startappad; import com.startapp.android.publish.startappsdk;  import java.text.numberformat; import java.util.arraylist; import java.util.list;  public class combertotaldraftdrafting extends appcompatactivity {     edittext inputbatttension, inputfeedamount, inputnoil, inputbattweight, inputsliverhank;     textview answer;     spinner spinner;     button calculate, buttonformula;     final context context = this;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         startappsdk.init(this, "210963358", true);         startappad.disablesplash();         setcontentview(r.layout.activity_comber_total_draft_drafting);         getsupportactionbar().setdisplayhomeasupenabled(true);         getsupportactionbar().sethomebuttonenabled(true);         inputbatttension = (edittext) findviewbyid(r.id.inputbatttensioncombertotaldraft);         inputbatttension.addtextchangedlistener(new numbertextwatcherforthousand(inputbatttension));         inputbattweight = (edittext) findviewbyid(r.id.inputbattweightcombertotaldraft);         inputbattweight.addtextchangedlistener(new numbertextwatcherforthousand(inputbattweight));         inputnoil = (edittext) findviewbyid(r.id.inputnoilbcombertotaldraft);         inputnoil.addtextchangedlistener(new numbertextwatcherforthousand(inputnoil));         inputfeedamount = (edittext) findviewbyid(r.id.inputfeedamountcombertotaldraft);         inputfeedamount.addtextchangedlistener(new numbertextwatcherforthousand(inputfeedamount));         inputsliverhank = (edittext) findviewbyid(r.id.inputsliverhankcombertotaldrfat);         inputsliverhank.addtextchangedlistener(new numbertextwatcherforthousand(inputsliverhank));         answer = (textview) findviewbyid(r.id.answercombertotaldraft);         calculate = (button) findviewbyid(r.id.calculatecombertotaldraft);         spinner = (spinner) findviewbyid(r.id.spinnerselectcountunit);         list<string> list1 = new arraylist<string>();         list1.add("ne");         list1.add("ktex");         arrayadapter<string> dataadapter1 = new arrayadapter<string>(this,                 r.layout.custom_simple_spinner, list1);         dataadapter1.setdropdownviewresource(r.layout.custom_spinner_dropdown);         spinner.setadapter(dataadapter1);         calculate.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                 int index = spinner.getselecteditemposition();                 double value1 = 0;                 double value2 = 0;                 double value3 = 0;                 double value4 = 0;                 double value5 = 0;                 if (inputbatttension.gettext().tostring().isempty() ||                         inputfeedamount.gettext().tostring().isempty() ||                         inputnoil.gettext().tostring().isempty() || inputbattweight.gettext().tostring().isempty()                         || inputsliverhank.gettext().tostring().isempty())                     toast.maketext(getapplicationcontext(), getresources().getstring(r.string.toastmessage3),                             toast.length_long).show();                 else {                     value1 = double.parsedouble(inputbatttension.gettext().tostring().replaceall(",", ""));                     value2 = double.parsedouble(inputfeedamount.gettext().tostring().replaceall(",", ""));                     value3 = double.parsedouble(inputnoil.gettext().tostring().replaceall(",", ""));                     value4 = double.parsedouble(inputbattweight.gettext().tostring().replaceall(",", ""));                     value5 = double.parsedouble(inputsliverhank.gettext().tostring().replaceall(",", ""));                 }                 if (index == 0) {                     double answer1 = 0;                     answer1 = (0.417 * value2 * value4 * ((100 - value1) / 100) * ((100 - value3) / 100) * value5);                     numberformat formatter = numberformat.getnumberinstance();                     formatter.setminimumfractiondigits(2);                     formatter.setmaximumfractiondigits(2);                     answer.settext(formatter.format(answer1) + " ");                 }                 if (index == 1) {                     double answer2 = 0;                     answer2 = (((0.245 / value5) * value2 * value4 * ((100 - value1) / 100) * ((100 - value3) / 100)));                     numberformat formatter = numberformat.getnumberinstance();                     formatter.setminimumfractiondigits(2);                     formatter.setmaximumfractiondigits(2);                     answer.settext(formatter.format(answer2) + " ");                 }             }         });         buttonformula = (button) findviewbyid(r.id.formulacombertotaldraft);         buttonformula.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view arg0) {                 final dialog dialog = new dialog(context);                 dialog.requestwindowfeature(window.feature_no_title);                 dialog.setcontentview(r.layout.layout_formula);                 textview title = (textview) dialog.findviewbyid(r.id.title);                 title.settext(r.string.combertotaldraftcalculation);                 imageview image = (imageview) dialog.findviewbyid(r.id.test_image);                 image.setimageresource(r.drawable.combertotaldraftne);                 imageview image1 = (imageview) dialog.findviewbyid(r.id.test_image1);                 image1.setimageresource(r.drawable.combertotaldraftktex);                 textview text = (textview) dialog.findviewbyid(r.id.text);                 text.settext(r.string.formula_combertotaldraftcalculation);                 button dialogbutton = (button) dialog.findviewbyid(r.id.dialogbuttonok);                 dialogbutton.setonclicklistener(new view.onclicklistener() {                     @override                     public void onclick(view v) {                         dialog.dismiss();                     }                 });                 dialog.show();             }         });     }     @override     public void onbackpressed() {         startappad.onbackpressed(this);         super.onbackpressed();     } } 

xml file

<?xml version="1.0" encoding="utf-8"?> <relativelayout     xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:background="@color/layoutbackgroundcolor"> <scrollview xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:layout_above="@+id/startappbanner"     android:fillviewport="true">      <relativelayout xmlns:android="http://schemas.android.com/apk/res/android"         xmlns:app="http://schemas.android.com/apk/res-auto"         xmlns:tools="http://schemas.android.com/tools"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:background="@color/layoutbackgroundcolor"         app:layout_behavior="@string/appbar_scrolling_view_behavior"         tools:context="sujaynambiar.paid.combertotaldraftdrafting"         tools:showin="@layout/activity_comber_total_draft_drafting">          <view             android:id="@+id/dot"             android:layout_width="fill_parent"             android:layout_height="3dp"             android:layout_marginbottom="@dimen/separator_textview"             android:layout_margintop="@dimen/firstviewmargintop"             android:background="@drawable/separator"             android:layertype="software" />          <linearlayout             android:id="@+id/rl1"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_below="@+id/dot"             android:layout_marginbottom="@dimen/gap_for_all"             android:orientation="horizontal"             android:weightsum="3">              <textview                 android:id="@+id/textview14"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="center"                 android:layout_marginend="@dimen/padding_left"                 android:layout_marginleft="@dimen/padding_left"                 android:layout_marginright="@dimen/padding_right"                 android:layout_marginstart="@dimen/padding_right"                 android:layout_weight="1.25"                 android:text="@string/showtext52"                 android:textcolor="@color/textviewtextcolor"                 android:textsize="@dimen/textviewsize" />              <edittext                 android:id="@+id/inputbatttensioncombertotaldraft"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="center"                 android:layout_marginend="@dimen/padding_left"                 android:layout_marginleft="@dimen/padding_left"                 android:layout_marginright="@dimen/padding_right"                 android:layout_marginstart="@dimen/padding_right"                 android:layout_weight="1.75"                 android:ems="10"                 android:gravity="center"                 android:inputtype="numberdecimal" />         </linearlayout>          <view             android:id="@+id/dot1"             android:layout_width="fill_parent"             android:layout_height="3dp"             android:layout_below="@+id/rl1"             android:layout_marginbottom="@dimen/separator_textview"             android:background="@drawable/separator"             android:layertype="software" />          <linearlayout             android:id="@+id/rl2"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_below="@+id/dot1"             android:layout_marginbottom="@dimen/gap_for_all"             android:orientation="horizontal"             android:weightsum="3">              <textview                 android:id="@+id/textview15"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="center"                 android:layout_marginend="@dimen/padding_left"                 android:layout_marginleft="@dimen/padding_left"                 android:layout_marginright="@dimen/padding_right"                 android:layout_marginstart="@dimen/padding_right"                 android:layout_weight="1.25"                 android:text="@string/showtext51"                 android:textcolor="@color/textviewtextcolor"                 android:textsize="@dimen/textviewsize" />              <edittext                 android:id="@+id/inputbattweightcombertotaldraft"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="center"                 android:layout_marginend="@dimen/padding_left"                 android:layout_marginleft="@dimen/padding_left"                 android:layout_marginright="@dimen/padding_right"                 android:layout_marginstart="@dimen/padding_right"                 android:layout_weight="1.75"                 android:ems="10"                 android:gravity="center"                 android:inputtype="numberdecimal" />         </linearlayout>          <view             android:id="@+id/dot2"             android:layout_width="fill_parent"             android:layout_height="3dp"             android:layout_below="@+id/rl2"             android:layout_marginbottom="@dimen/separator_textview"             android:background="@drawable/separator"             android:layertype="software" />          <linearlayout             android:id="@+id/rl3"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_below="@+id/dot2"             android:layout_marginbottom="@dimen/gap_for_all"             android:orientation="horizontal"             android:weightsum="3">              <textview                 android:id="@+id/textview16"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="center"                 android:layout_marginend="@dimen/padding_left"                 android:layout_marginleft="@dimen/padding_left"                 android:layout_marginright="@dimen/padding_right"                 android:layout_marginstart="@dimen/padding_right"                 android:layout_weight="1.25"                 android:text="@string/showtext50"                 android:textcolor="@color/textviewtextcolor"                 android:textsize="@dimen/textviewsize" />              <edittext                 android:id="@+id/inputnoilbcombertotaldraft"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="center"                 android:layout_marginend="@dimen/padding_left"                 android:layout_marginleft="@dimen/padding_left"                 android:layout_marginright="@dimen/padding_right"                 android:layout_marginstart="@dimen/padding_right"                 android:layout_weight="1.75"                 android:ems="10"                 android:gravity="center"                 android:inputtype="numberdecimal" />         </linearlayout>          <view             android:id="@+id/dot5"             android:layout_width="fill_parent"             android:layout_height="3dp"             android:layout_below="@+id/rl3"             android:layout_marginbottom="@dimen/separator_button"             android:background="@drawable/separator"             android:layertype="software" />          <linearlayout             android:id="@+id/rl4"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_below="@+id/dot5"             android:layout_marginbottom="@dimen/gap_for_all"             android:orientation="horizontal"             android:weightsum="3">              <textview                 android:id="@+id/textview17"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="center"                 android:layout_marginend="@dimen/padding_left"                 android:layout_marginleft="@dimen/padding_left"                 android:layout_marginright="@dimen/padding_right"                 android:layout_marginstart="@dimen/padding_right"                 android:layout_weight="1.25"                 android:text="@string/showtext49"                 android:textcolor="@color/textviewtextcolor"                 android:textsize="@dimen/textviewsize" />              <edittext                 android:id="@+id/inputfeedamountcombertotaldraft"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="center"                 android:layout_marginend="@dimen/padding_left"                 android:layout_marginleft="@dimen/padding_left"                 android:layout_marginright="@dimen/padding_right"                 android:layout_marginstart="@dimen/padding_right"                 android:layout_weight="1.75"                 android:ems="10"                 android:gravity="center"                 android:inputtype="numberdecimal" />         </linearlayout>          <view             android:id="@+id/dot6"             android:layout_width="fill_parent"             android:layout_height="3dp"             android:layout_below="@+id/rl4"             android:layout_marginbottom="@dimen/separator_textview"             android:background="@drawable/separator"             android:layertype="software" />          <textview             android:id="@+id/textview18"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_below="@+id/dot6"             android:layout_marginbottom="@dimen/textview_spinner"             android:layout_marginend="@dimen/padding_left"             android:layout_marginleft="@dimen/padding_left"             android:layout_marginright="@dimen/padding_right"             android:layout_marginstart="@dimen/padding_right"             android:text="@string/showtext43"             android:textcolor="@color/textviewtextcolor"             android:textsize="@dimen/textviewsize" />          <textview             android:id="@+id/textview11"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_below="@+id/textview18"             android:layout_marginbottom="@dimen/textview_spinner"             android:layout_marginend="@dimen/padding_left"             android:layout_marginleft="@dimen/padding_left"             android:layout_marginright="@dimen/padding_right"             android:layout_marginstart="@dimen/padding_right"             android:text="@string/showtext30a"             android:textcolor="@color/textviewtextcolor"             android:textsize="@dimen/textviewsize" />          <linearlayout             android:id="@+id/rl5"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_below="@+id/textview11"             android:layout_marginbottom="@dimen/gap_for_all"             android:orientation="horizontal"             android:weightsum="3">              <spinner                 android:id="@+id/spinnerselectcountunit"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="center"                 android:layout_marginend="@dimen/padding_left"                 android:layout_marginleft="@dimen/padding_left"                 android:layout_marginright="@dimen/padding_right"                 android:layout_marginstart="@dimen/padding_right"                 android:layout_weight="1.25"                 android:gravity="center"                 android:spinnermode="dialog" />              <edittext                 android:id="@+id/inputsliverhankcombertotaldrfat"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="center"                 android:layout_marginend="@dimen/padding_left"                 android:layout_marginleft="@dimen/padding_left"                 android:layout_marginright="@dimen/padding_right"                 android:layout_marginstart="@dimen/padding_right"                 android:layout_weight="1.75"                 android:ems="10"                 android:gravity="center"                 android:inputtype="numberdecimal" />         </linearlayout>          <view             android:id="@+id/dot7"             android:layout_width="fill_parent"             android:layout_height="3dp"             android:layout_below="@+id/rl5"             android:layout_marginbottom="@dimen/separator_button"             android:background="@drawable/separator"             android:layertype="software" />          <button             android:id="@+id/calculatecombertotaldraft"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_below="@+id/dot7"             android:layout_marginbottom="@dimen/button_separator"             android:layout_marginend="@dimen/padding_left"             android:layout_marginleft="@dimen/padding_left"             android:layout_marginright="@dimen/padding_right"             android:layout_marginstart="@dimen/padding_right"             android:background="@drawable/button_background"             android:text="@string/calculate"             android:textcolor="@color/buttontextcolor"             android:textsize="@dimen/buttontext" />          <view             android:id="@+id/dot8"             android:layout_width="fill_parent"             android:layout_height="3dp"             android:layout_below="@+id/calculatecombertotaldraft"             android:layout_marginbottom="@dimen/separator_answer"             android:background="@drawable/separator"             android:layertype="software" />          <textview             android:id="@+id/answercombertotaldraft"             android:layout_width="match_parent"             android:layout_height="@dimen/answerviewsize"             android:layout_below="@+id/dot8"             android:layout_marginbottom="@dimen/answerview_separator"             android:layout_marginend="@dimen/padding_left"             android:layout_marginleft="@dimen/padding_left"             android:layout_marginright="@dimen/padding_right"             android:layout_marginstart="@dimen/padding_right"             android:gravity="center"             android:text="@string/answer"             android:textcolor="@color/textviewtextcolor"             android:textsize="@dimen/answerview" />          <view             android:id="@+id/dot10"             android:layout_width="fill_parent"             android:layout_height="3dp"             android:layout_below="@+id/answercombertotaldraft"             android:layout_marginbottom="@dimen/separator_button"             android:background="@drawable/separator"             android:layertype="software" />          <button             android:id="@+id/formulacombertotaldraft"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_below="@+id/dot10"             android:layout_marginbottom="@dimen/button_separator"             android:layout_marginend="@dimen/padding_left"             android:layout_marginleft="@dimen/padding_left"             android:layout_marginright="@dimen/padding_right"             android:layout_marginstart="@dimen/padding_right"             android:background="@drawable/button_background"             android:text="@string/formula"             android:textcolor="@color/buttontextcolor"             android:textsize="@dimen/buttontext" />          <view             android:id="@+id/dot9"             android:layout_width="fill_parent"             android:layout_height="3dp"             android:layout_below="@+id/formulacombertotaldraft"             android:layout_marginbottom="@dimen/separator_textview"             android:background="@drawable/separator"             android:layertype="software" />      </relativelayout> </scrollview>     <com.startapp.android.publish.banner.banner         android:id="@+id/startappbanner"         android:layout_width="wrap_content"         android:layout_alignparentbottom="true"         android:layout_height="wrap_content"         android:layout_centerhorizontal="true"/> </relativelayout>