编译错误:缺少return语句

Question

class Employee
{
int emp_no;
String emp_name;
double emp_sal;

public Employee(int e_no,String e_name,double e_sal)
{
emp_no=e_no;
emp_name=e_name;
emp_sal=e_sal;
}

public double calBonus()
{
return (emp_sal/10);
}

public void display()
{
System.out.println("Employee No: "+this.emp_no);
System.out.println("Employee Name: "+this.emp_name);
System.out.println("Employee Gross Salary: "+ (emp_sal+calBonus()));
}

}

class Clerk extends Employee
{
String Grade;

public Clerk(int e_no,String e_name,double e_sal,String e_Grade)
{
super(e_no,e_name,e_sal); 
Grade=e_Grade;
this.set_Grade(e_Grade);
}
String set_Grade(String e_Grade)
{
**this.Grade=e_Grade;
}
String get_Grade()
{
return this.Grade;
}**

public void display()
{
super.display();
System.out.println("Grade: " + this.Grade);
}

}

class PaySlip
{
public static void main(String args[])
{
Employee c1;

c1=new Clerk(76,"Saman",12000.50,"Grade1");

c1.display();
}
}

**

Bolded系列中出了点问题.但是我无法弄明白.当我编译它时会显示一条错误,显示"缺少return statement'}'.

**

Answer 1

String set_Grade(String e_Grade)
{
    this.Grade=e_Grade;
}

应该

void set_Grade(String e_Grade)
{
    this.Grade=e_Grade;
}

你已经声明了返回类型String应该是void因为你没有return语句它是一个setter.