gistfile1.txt

// Works //

public class MainActivity extends AppCompatActivity {

            // ...
            
            @Override
            protected void onCreate(Bundle savedInstanceState) {

            super.onCreate(savedInstanceState);
            ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);

            ClickHandlers handlers = new ClickHandlers(MainActivity.this);
            binding.setHandlers(handlers);

            fab.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        Intent intent = new Intent(MainActivity.this, NewWordActivity.class);
                        startActivityForResult(intent, NEW_WORD_ACTIVITY_REQUEST_CODE);
                    }
             });
                    
            // ...
}
        
===========================================================

// Does not work //

" java.lang.NullPointerException: Attempt to invoke virtual method 'android.app.ActivityThread$ApplicationThread android.app.ActivityThread.getApplicationThread()' on a null object reference "
@Line 40 (in this matter)

public class ClickHandlers extends Activity {

    Context context;

    public void fabClicked(View view) {
            Intent intent = new Intent(context, NewWordActivity.class);
            startActivityForResult(intent, NEW_WORD_ACTIVITY_REQUEST_CODE);
    }
}

===========================================================

<android.support.design.widget.FloatingActionButton
            // ...
            android:onClick="@{handlers.fabClicked}"
            // ... />

public class MainActivity extends AppCompatActivity {

            // ...
            
            @Override
            protected void onCreate(Bundle savedInstanceState) {

            super.onCreate(savedInstanceState);
            ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);

            ClickHandlers handlers = new ClickHandlers();
            binding.setHandlers(handlers);

            fab.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        Intent intent = new Intent(MainActivity.this, NewWordActivity.class);
                        startActivityForResult(intent, NEW_WORD_ACTIVITY_REQUEST_CODE);
                    }
             });
                    
            // ...
}

public class ClickHandlers {
    public void fabClicked(View view) {
            Intent intent = new Intent(view.getContext(), NewWordActivity.class);
            startActivityForResult(intent, NEW_WORD_ACTIVITY_REQUEST_CODE);
    }
}