getting "java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener)' on a null object reference"

I was trying to make firebase authentication but for some reason this button is giving a NullPointerException, I checked the button name and I cant find why it is throwing such error

the code and the Logcat are included below

Logcat:

     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at com.anan.login.MainActivity.onCreate(MainActivity.java:45)
at android.app.Activity.performCreate(Activity.java:7802)
at android.app.Activity.performCreate(Activity.java:7791)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) 
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
at android.os.Handler.dispatchMessage(Handler.java:107) 
at android.os.Looper.loop(Looper.java:214) 
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) 

Main.java:

public class MainActivity extends AppCompatActivity {
EditText mEmail,mPassword;
Button mButton;
TextView Login;
FirebaseAuth fAuth;
ProgressBar progressBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mEmail = findViewById(R.id.Email);
mPassword = findViewById((R.id.Password));
//mButton = findViewById(R.id.button);
progressBar = findViewById(R.id.progressBar);
fAuth = FirebaseAuth.getInstance();
if (fAuth.getCurrentUser() != null){
startActivity(new Intent(getApplicationContext(),Main2Activity.class));
finish();
}
mButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String Email = mEmail.getText().toString().trim();
String password = mPassword.getText().toString().trim();
progressBar.setVisibility(View.VISIBLE);
//Register user in Firebase
fAuth.createUserWithEmailAndPassword(Email,password).addOnCompleteListener(new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()){
Toast.makeText(MainActivity.this, "Register Successful", Toast.LENGTH_SHORT).show();
startActivity(new Intent(getApplicationContext(),Main2Activity.class));
}else{
Toast.makeText(MainActivity.this, "Register failed", Toast.LENGTH_SHORT).show();
}
}
});
}
});
}
}

Main.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<EditText
android:id="@+id/Email"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textPersonName"
android:text="Email"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.52"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.25" />
<EditText
android:id="@+id/Password"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textPersonName"
android:text="Password"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.52"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="@+id/imageView"
app:layout_constraintVertical_bias="0.405" />
<Button
android:id="@+id/button"
android:layout_width="79dp"
android:layout_height="52dp"
android:text="Button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

...............................................................................................................

You never assigned a value to mButton. You have an assignment commented out:

        //mButton = findViewById(R.id.button);

If you don't assign it a value which is an actual View in your view hierarchy, it's going to retain the default value of null.

Also, I'm noticing that you never inflated your layout. You simply don't have any views to work with at all.

Bind view to your activity before accessing its widget

Add below line just after super.onCreate(savedInstanceState); inside onCreate(..) method

   setContentView(R.layout.main);

1. You did not specify the layout in your onCreate method so your main activity has no layout to inflate

2. You did not assign a value to mButton in your onCreate method so it is authomatically assigned null.

Replace your onCreate code with the following:

    @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);                   //Specify your layout
mEmail = findViewById(R.id.Email);
mPassword = findViewById((R.id.Password));
mButton = findViewById(R.id.button);             //Assign a value to mButton from your layout
progressBar = findViewById(R.id.progressBar);
fAuth = FirebaseAuth.getInstance();
if (fAuth.getCurrentUser() != null){
startActivity(new Intent(getApplicationContext(),Main2Activity.class));
finish();
}
}