文件名:Project.java
class Human
{
   char name,nativeplace;
   int height,weight;
   void language()
   {
      System.out.println("human speak");
   }
  }
class Technician extends Human
{
 char department,technique;
 void express()
 {
   System.out.println("This person is at leaste a master!");
 }
}
class Artlist extends Technician
{
   char artdegreen,arttask;
   void task(artdegreen,arttask)
   {
      System.out.println("what art_degreen,what art_task!");
   }
}
class Programmer extends Technician
{
   char prodegreen,protask;
   void task(prodegreen,protask)
   {
      System.out.println("what pro_degreen,what pro_task!");
   }
}
class Network extends Technician
{
   char netdegreen,nettask;
   void task(netdegreen,nettask)
   {
      System.out.println("what net_degreen,what net_task!");
   }
}
class Project
{
 public static void main(sting[] args)
 {
   Human hu=new Human();
   hu.language();
   Technician te=new Technician();
   te.express();
   Artlist ar=new Artlist();
   ar.artdegreen="yj";
   ar.arttask="painting";
   ar.task("yj","painting");
 }
}

你的void task()里面写得不对，方法的签名应该是method_name(class_name1 arg_name1,class_name2 arg_name2)

谢谢,再试试,基础相当的不好,努力中....

努力就好

纠正一下自己，是method_name(typename1 arg1, typename2 arg2)