Java类抛出java.lang.NullPointerException [重复]

Java类抛出java.lang.NullPointerException [重复]

嗨，大家好我是Java新手，为什么会引发空指针异常？我的客户类别

package com.syncfusion;

import java.util.List;

public class Customers {

    private List<String> customerNamesList;

    public void addCustomerName(String customerName) {

        customerNamesList.add(customerName);
        System.out.println(customerName);

    }


    public void printAllCustomers() {
        for(String customer : customerNamesList) {

            System.out.println(customer);


        }
    }
}

我的主要功能如下所示：

package com.syncfusion;

public class Persons {

public static void main(String[] args) {
     Customers customer = new Customers();
     customer.addCustomerName("Inteflex Inc");




}

}

为什么它抛出空指针？我希望我已经实例化了Customer Class，但是它有错误

问题来源：stackoverflow