作业3-8

为什么代码运行后所赋值的属性如姓名年龄性别等都为空值，请问出现这种错误，一般是因为什么原因？

class test	：
Department dep1=new Department("人事部");
		Department dep2=new Department("市场部");
		//测试Position
		Position pos1=new Position("经理");
		Position pos2=new Position("助理");
		Position pos3=new Position("职员");
		//测试Employee
		Employee emp1=new Employee("张铭","S001",29,"男");
		System.out.println(emp1.introduction(dep1, pos1));
		System.out.println("========================================");
		
	class employee：		
		
		public String introduction(Department myDepartment,Position myPosition) {
		String str = "姓名：" + this.getEmployeeName() + "\n工号：" + this.getEmployeeNo() + "\n性别："
				+ this.getEmployeeSex() + "\n年龄：" + this.getEmployeeAge()+"\n职务："+this.getEmployeeDepartment().getDepartmentName()+this.getEmployeePosition().getPositionName();
		return str;
	}