ERROR: ANDROID STUDIO FLAMINGO 2022.2.1 android.text.Editable android.widget.EditText.getText()' on a null object reference

Question

FATAL EXCEPTION: main Process: com.example.sqlite8, PID: 7892 java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference at com.example.sqlite8.MainActivity$1.onClick(MainActivity.java:37)

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package com.example.sqlite8;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Switch;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    //references to buttons and other controls on layout
    Button btn_add, btn_viewAll;
    EditText et_name, et_age;
    Switch sw_activeCustomer;
    ListView lv_customerList;

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

    btn_add = findViewById(R.id.btn_add);
    btn_viewAll = findViewById(R.id.btn_viewAll);
    et_age = findViewById(R.id.et_age);
    sw_activeCustomer = findViewById(R.id.sw_activeCustomer);
    lv_customerList = findViewById(R.id.lv_customerList);

    //button listeners for the add and viewall buttons
        btn_add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

              CustomerModel customerModel=new CustomerModel(-1, et_name.getText().toString(), Integer.parseInt(et_age.getText().toString()), sw_activeCustomer.isChecked());

                Toast.makeText(MainActivity.this, customerModel.toString(), Toast.LENGTH_SHORT).show();


            }
        });

        btn_viewAll.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "View All Button", Toast.LENGTH_SHORT).show();

            }
        });



    }
}

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This is in Android Studio: when i enter a customer name and the customers age i the form, i click on the Add Button and it crashes.