出现了Could not find the main class的错误

我写了一个关于线程的java程序，出现了Could not find the main class的提示，错误如下java.lang.SecurityException: Prohibited package name: java.jion
at java.lang.ClassLoader.preDefineClass(Unknown Source)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
Exception in thread "main" ；

我的源代码：package java.jion;


public class Cooking {
public static void main(String argv[]){
Thread mother=new Thread(new MotherThread());
mother.start();
}

}

package java.jion;

public class MotherThread implements Runnable {
public void run(){
System.out.println("妈妈准备煮饭");
System.out.println("妈妈发现米酒用完了");
System.out.println("妈妈叫儿子去买米酒");
Thread son=new Thread(new SonThread());
son.start();
System.out.println("妈妈等待儿子把米酒买回来");
try {
son.join();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("妈妈开始煮饭");
System.out.println("妈妈煮好饭了");
}
/* public static void main(String args[]){
MotherThread mother=new MotherThread();
mother.run();
}
*/
}package java.jion;

public class SonThread implements Runnable {

public void run(){
System.out.println("儿子出去买米酒");
System.out.println("儿子买东西回来需要五分钟");
try {
for(int i=0;i<=5;i++)
{
Thread.sleep(1000);
System.out.print(i+"分钟");
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
System.err.println("儿子发生意外");
}
System.out.println("\n儿子买米酒回来了");
}
}
谁能帮我看看 是什么地方的问题