Don't know why I am getting Null Pointer exception

Question

Here I am retrieving data from an API everything works fine but 1. Suces is showing on Toast then App crashes

public class MainActivity extends AppCompatActivity {


    public TextView textView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = findViewById(R.id.textview);
        MyWebService myWebService = MyWebService.retrofit.create(MyWebService.class);
        Call<Train>  call = myWebService.getTrain();
        call.enqueue(new Callback<Train>() {
            @Override
            public void onResponse(Call<Train> call, Response<Train> response) {
                if(response.isSuccessful() && response.body()!=null)
                {

                    Train train = response.body();
                    Toast.makeText(getApplicationContext(),"Sucess",Toast.LENGTH_LONG).show();
                    textView.setText(train.getTrain2().getName());
                }
            }

            @Override
            public void onFailure(Call<Train> call, Throwable t) {
                Toast.makeText(getApplicationContext(),t.getMessage(),Toast.LENGTH_LONG).show();

            }
        });
    }
}

I am getting error at this line

textView.setText(train.getTrain2().getName());

But I initialize the textview and also checking response!=null

Error is

02-14 22:41:40.003 1557-1557/? E/Zygote: v2
02-14 22:41:40.003 1557-1557/? E/Zygote: accessInfo : 0
02-14 22:41:41.963 1557-1557/com.piyushjaiswal121.rail E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.piyushjaiswal121.rail, PID: 1557
    java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.piyushjaiswal121.rail.Train2.getName()' on a null object reference
        at com.piyushjaiswal121.rail.MainActivity$1.onResponse(MainActivity.java:36)
        at retrofit2.ExecutorCallAdapterFactory$ExecutorCallbackCall$1$1.run(ExecutorCallAdapterFactory.java:70)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:148)
        at android.app.ActivityThread.main(ActivityThread.java:7325)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)

`Attempt to invoke virtual method 'java.lang.String com.piyushjaiswal121.rail.Train2.getName()' on a null object reference` this is why, just because the response isn't null doesn't mean that what you're trying to access inside it isn't null — a_local_nobody, Feb 14 '20 at 17:21
System.out.println(response.body()+" in system"); using this i get'02-14 22:56:38.734 11454-11454/com.piyushjaiswal121.rail I/System.out: com.piyushjaiswal121.rail.Train@214a858in system Hence not a null pointer exception — Pankaj Maurya, Feb 14 '20 at 17:28

score 0 · Answer 1 · answered Feb 14 '20 at 17:29

The reason why you're getting a Null Pointer Exception is because apparently train2 is null.

An approach to avoid that exception could be just check if train2 is null or not

if(train.getTrain2()!=null)                        
   textView.setText(train.getTrain2().getName());

Don't know why I am getting Null Pointer exception

1 Answers1