MainActivity.java

package com.lgmbrydan.uselessbutton;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button crashButton = findViewById(R.id.crashButton);
        crashButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // Simulate a crash by causing a null pointer exception
                String crashString = null;
                crashString.length(); // This will cause a NullPointerException
            }
        });
    }
}