关于java：Abstract方法中的构造函数

Constructor in Abstract method

本问题已经有最佳答案，请猛点这里访问。

当抽象方法不能实例化时，为什么抽象方法中有构造函数？我很困惑……

来自tutorialspoint.com的代码

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public abstract class Employee
{
private String name;
private String address;
private int number;
public Employee(String name, String address, int number)
{
System.out.println("Constructing an Employee");
this.name = name;
this.address = address;
this.number = number;
}
public double computePay()
{
System.out.println("Inside Employee computePay");
return 0.0;
}
public void mailCheck()
{
System.out.println("Mailing a check to" + this.name
+"" + this.address);
}
public String toString()
{
return name +"" + address +"" + number;
}
public String getName()
{
return name;
}
public String getAddress()
{
return address;
}
public void setAddress(String newAddress)
{
address = newAddress;
}
public int getNumber()
{
return number;
}
}

现在可以尝试实例化Employee类，如下所示：

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* File name : AbstractDemo.java */
public class AbstractDemo
{
public static void main(String [] args)
{
/* Following is not allowed and would raise error */
Employee e = new Employee("George W.","Houston, TX", 43);

System.out.println("
Call mailCheck using Employee reference--");
e.mailCheck();
}
}

编译上述类时，会出现以下错误：

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Employee.java:46: Employee is abstract; cannot be instantiated
Employee e = new Employee("George W.","Houston, TX", 43);
^
1 error

我遇到的问题是，如果必须显示错误，为什么抽象类中的构造函数是出于什么原因？