I have a Problem with Android Studio an Java?

Hello i have a question my app keeps crashing i only have this activity with this code:

package com.example.tst;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.text.Editable;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

import org.w3c.dom.Text;

public class MainActivity extends AppCompatActivity {
    private EditText startTime;
    private EditText endTime;
    private TextView textView;

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

    public void start(View view){
        startTime = findViewById(R.id.editText);
        endTime = findViewById(R.id.editText1);
        textView = findViewById(R.id.textView3);

        int start = Integer.parseInt(startTime.getText().toString());
        int end = Integer.parseInt(endTime.getText().toString());



        textView.setText(start + end);


    }
}

I want to calculate the sum of both editText objects an want them to display in the text view! And this is the Error: I have tried changing the EditText Objects in the xml but this does not work.

E/com.example.ts: Invalid ID 0x00000008.
E/InputEventSender: Exception dispatching finished signal.
E/MessageQueue-JNI: Exception in MessageQueue callback: handleReceiveCallback
E/MessageQueue-JNI: java.lang.IllegalStateException: Could not execute method for android:onClick
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:390)
        at android.view.View.performClick(View.java:7125)
        at android.view.View.performClickInternal(View.java:7102)
        at android.view.View.onKeyUp(View.java:14143)
        at android.widget.TextView.onKeyUp(TextView.java:8586)
        at android.view.KeyEvent.dispatch(KeyEvent.java:2825)
        at android.view.View.dispatchKeyEvent(View.java:13352)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1922)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1922)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1922)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1922)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1922)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1922)
        at com.android.internal.policy.DecorView.superDispatchKeyEvent(DecorView.java:453)
        at com.android.internal.policy.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1839)
        at android.app.Activity.dispatchKeyEvent(Activity.java:3953)
        at androidx.core.app.ComponentActivity.superDispatchKeyEvent(ComponentActivity.java:108)
        at androidx.core.view.KeyEventDispatcher.dispatchKeyEvent(KeyEventDispatcher.java:84)
        at androidx.core.app.ComponentActivity.dispatchKeyEvent(ComponentActivity.java:126)
        at androidx.appcompat.app.AppCompatActivity.dispatchKeyEvent(AppCompatActivity.java:535)
        at androidx.appcompat.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:59)
        at androidx.appcompat.app.AppCompatDelegateImpl$AppCompatWindowCallback.dispatchKeyEvent(AppCompatDelegateImpl.java:2533)
        at com.android.internal.policy.DecorView.dispatchKeyEvent(DecorView.java:367)
        at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:5413)
        at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:5281)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4788)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4841)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4807)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4947)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4815)
        at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:5004)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4788)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4841)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4807)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4815)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4788)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4841)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4807)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4980)
        at android.view.ViewRootImpl$ImeInputStage.onFinishedInputEvent(ViewRootImpl.java:5141)
        at android.view.inputmethod.InputMethodManager$PendingEvent.run(InputMethodManager.java:3064)
        at android.view.inputmethod.InputMethodManager.invokeFinishedInputEventCallback(InputMethodManager.java:2607)
        at android.view.inputmethod.InputMethodManager.finishedInputEvent(InputMethodManager.java:2598)
        at android.view.inputmethod.InputMethodManager$ImeInputEventSender.onInputEventFinished(InputMethodManager.java:3041)
        at android.view.InputEventSender.dispatchInputEventFinished(InputEventSender.java:143)
        at android.os.MessageQueue.nativePollOnce(Native Method)
        at android.os.MessageQueue.next(MessageQueue.java:336)
        at android.os.Looper.loop(Looper.java:174)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
    Cau
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.tst, PID: 8996
    java.lang.IllegalStateException: Could not execute method for android:onClick
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:390)
        at android.view.View.performClick(View.java:7125)
        at android.view.View.performClickInternal(View.java:7102)
        at android.view.View.onKeyUp(View.java:14143)
        at android.widget.TextView.onKeyUp(TextView.java:8586)
        at android.view.KeyEvent.dispatch(KeyEvent.java:2825)
        at android.view.View.dispatchKeyEvent(View.java:13352)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1922)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1922)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1922)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1922)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1922)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1922)
        at com.android.internal.policy.DecorView.superDispatchKeyEvent(DecorView.java:453)
        at com.android.internal.policy.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1839)
        at android.app.Activity.dispatchKeyEvent(Activity.java:3953)
        at androidx.core.app.ComponentActivity.superDispatchKeyEvent(ComponentActivity.java:108)
        at androidx.core.view.KeyEventDispatcher.dispatchKeyEvent(KeyEventDispatcher.java:84)
        at androidx.core.app.ComponentActivity.dispatchKeyEvent(ComponentActivity.java:126)
        at androidx.appcompat.app.AppCompatActivity.dispatchKeyEvent(AppCompatActivity.java:535)
        at androidx.appcompat.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:59)
        at androidx.appcompat.app.AppCompatDelegateImpl$AppCompatWindowCallback.dispatchKeyEvent(AppCompatDelegateImpl.java:2533)
        at com.android.internal.policy.DecorView.dispatchKeyEvent(DecorView.java:367)
        at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:5413)
        at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:5281)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4788)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4841)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4807)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4947)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4815)
        at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:5004)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4788)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4841)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4807)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4815)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4788)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4841)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4807)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4980)
        at android.view.ViewRootImpl$ImeInputStage.onFinishedInputEvent(ViewRootImpl.java:5141)
        at android.view.inputmethod.InputMethodManager$PendingEvent.run(InputMethodManager.java:3064)
        at android.view.inputmethod.InputMethodManager.invokeFinishedInputEventCallback(InputMethodManager.java:2607)
        at android.view.inputmethod.InputMethodManager.finishedInputEvent(InputMethodManager.java:2598)
        at android.view.inputmethod.InputMethodManager$ImeInputEventSender.onInputEventFinished(InputMethodManager.java:3041)
        at android.view.InputEventSender.dispatchInputEventFinished(InputEventSender.java:143)
        at android.os.MessageQueue.nativePollOnce(Native Method)
        at android.os.MessageQueue.next(MessageQueue.java:336)
        at android.os.Looper.loop(Looper.java:174)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime:     at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Method.invoke(Native Method)
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
            ... 51 more
     Caused by: android.content.res.Resources$NotFoundException: String resource ID #0x8
        at android.content.res.Resources.getText(Resources.java:367)
        at android.widget.TextView.setText(TextView.java:6370)
        at com.example.tst.MainActivity.start(MainActivity.java:35)
            ... 53 more

I hope you can help me i have no idea.