Wsrtjtyk

I have 2 modules in my application as follow app and interface. interface was an imported aar file.
I am trying to launch an activity in the interface module but every time the application crashes. Launching activities on the app module works fine
I had tried the other solutions available in this forum but was in vain. Find the codes below

QuestionAnalyser class

    package com.example.dell.bubblebot;



import android.content.Intent;

import android.os.Bundle;

import android.support.annotation.NonNull;

import android.support.v7.app.AppCompatActivity;

import android.widget.Toast;



import com.example.dell.yandexapilanguagetranslator.Translator;

import com.google.firebase.database.DataSnapshot;

import com.google.firebase.database.DatabaseError;

import com.google.firebase.database.DatabaseReference;

import com.google.firebase.database.FirebaseDatabase;

import com.google.firebase.database.ValueEventListener;



import java.util.ArrayList;

import java.util.List;





public class QuestionAnalyser extends AppCompatActivity {

    public static String question;

    public  static String words;

    String entityIdentified;

    static boolean identified = false;

    DatabaseReference entityRef;

    TranslatorServant t = new TranslatorServant();



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_interface);

        Translator.setKey ("trnsl.1.1.20181013T134643Z.debdb5811d6caba2.3a4daf18b25c9f4b97662d5e9ac45ed81b199c84");



    }



    public void analyse(String userQues) {

            TranslatorServant t = new TranslatorServant();

            question = userQues.replaceAll("\p{Punct}|\d", "");

          //  question = t.translateText(userQues).replaceAll("\p{Punct}|\d", "");

              words = question.split(" ");

            getEntity(words);

    }



    private void getEntity(final String words) {

                entityRef = FirebaseDatabase.getInstance().getReference().child("IRAdata").child("Entities");

                entityRef.addValueEventListener(new ValueEventListener() {

                    @Override

                    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

                        for (DataSnapshot entity : dataSnapshot.getChildren()) {

                            String synonyms = entity.child("syn").getValue().toString().split(",");

                            for (String syn : synonyms) {

                                for (String word : words) {

                                    if (word.equalsIgnoreCase(syn) || question.equalsIgnoreCase(syn)) {

                                        entityIdentified = entity.getKey();

                                        identified = true;



                                    }

                                }

                            }

                        }

                        check(words);

                    }

                    @Override

                    public void onCancelled(@NonNull DatabaseError databaseError) {

                        Toast.makeText(getApplicationContext(), databaseError.getMessage(), Toast.LENGTH_SHORT).show();



                    }



                });

    }





    public void mimicOtherMessage(String message) {

        ChatMessage chatMessage = new ChatMessage(message, false);

        Interface.madapter.add(chatMessage);

    }



    public void mimicOtherMessage() {

        ChatMessage chatMessage = new ChatMessage(null, false);

        Interface.madapter.add(chatMessage);

    }



    public void check(String words) {

        if (identified == true) {

            initialiseEntityServant(entityIdentified, question, words);

        }

        if (identified == false) {

            for (String yes : YesNo.yes) {

                for (String w : words) {

                    if (w.equalsIgnoreCase(yes) || question.equalsIgnoreCase(yes)) {

                        identified = true;

                        entityIdentified = "basic";

                        initialiseEntityServant(entityIdentified, question, words);

                    }

                }

                for (String no : YesNo.no) {

                    for (String w : words) {

                        if (w.equalsIgnoreCase(no) || question.equalsIgnoreCase(no)) {

                            identified = true;

                            entityIdentified = "basic";

                            initialiseEntityServant(entityIdentified, question, words);

                        }

                    }

                }



            }

        }

        if (identified == false) {

            mimicOtherMessage("Sorry, I failed to understand your question.");

        }

    }



    private void initialiseEntityServant(String ent, final String userQues, final String words) {

        if (ent.equalsIgnoreCase("cuisine")) {

           cuisine c=new cuisine();

           c.analyse();

        }

        if(ent.equalsIgnoreCase("basic")){

            final List<String> urlsList = new ArrayList<String>();

            final List<String> descList = new ArrayList<String>();

            urlsList.add("https://media.timeout.com/images/103708802/image.jpg");

            urlsList.add(""https://images.myguide-cdn.com/mauritius/companies/eighty-eight-chinese-restaurant/large/eighty-eight-chinese-restaurant-492783.png");



            descList.add("A Chinese dish of small steamed or fried savoury dumplings containing various fillings. Definitely worth a try");

            descList.add("Traditionally, this Chinese chicken dish is a dry-stir fry — not a lot of sauce is added into Kung Pao chicken. However, with the amount of flavour explosions happening in this dish, you don’t miss OR want any more sauce.");

            Intent i= new Intent(getApplicationContext(),gallery.class);

            i.putExtra("urls",urlsList.toArray());

            i.putExtra("desc",descList.toArray());

            startActivity(i);

        }



        // will need to initialise other classes

    }

    //add class to check if question and answer already exists



}

In this code i am calling the gallery activity 

gallery class:

package com.example.dell.bubblebot;



import android.support.v4.view.ViewPager;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.widget.TextView;





public class gallery extends AppCompatActivity {

    public static Stringdesc;

    public static TextView descTextbox;



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_gallery);

        descTextbox=(TextView)findViewById(R.id.desc);

        ViewPager viewPager=findViewById(R.id.view_pager);

        String imageUrls=getIntent().getStringArrayExtra("urls");

        String  descArr=getIntent().getStringArrayExtra("desc");

        desc=descArr;

        ViewPagerAdapter adapter= new ViewPagerAdapter(this,imageUrls);

        viewPager.setAdapter(adapter);



    }



}

Error message:

E/AndroidRuntime: FATAL EXCEPTION: main

                  Process: com.samples.chatbotsample1, PID: 14653

                  java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference

                      at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:112)

                      at com.example.dell.bubblebot.QuestionAnalyser.initialiseEntityServant(QuestionAnalyser.java:126)

                      at com.example.dell.bubblebot.QuestionAnalyser.check(QuestionAnalyser.java:93)

                      at com.example.dell.bubblebot.QuestionAnalyser$1.onDataChange(QuestionAnalyser.java:61)

                      at com.google.firebase.database.obfuscated.zzap.zza(com.google.firebase:firebase-database@@16.0.3:75)

                      at com.google.firebase.database.obfuscated.zzca.zza(com.google.firebase:firebase-database@@16.0.3:63)

                      at com.google.firebase.database.obfuscated.zzcd$1.run(com.google.firebase:firebase-database@@16.0.3:55)

                      at android.os.Handler.handleCallback(Handler.java:739)

                      at android.os.Handler.dispatchMessage(Handler.java:95)

                      at android.os.Looper.loop(Looper.java:148)

                      at android.app.ActivityThread.main(ActivityThread.java:7406)

                      at java.lang.reflect.Method.invoke(Native Method)

                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)

                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)

Notice:

Class A { ...

}

getApplicationContext belongs to abstract class Context, if you want to use this method in your custom class, the class should extends Context or any of its sub class, such as Application,Activity, etc.