我有一个很小的程序，只有一个Java文件，里面有主方法。我用和在我的Ubuntu终端上测试了这个程序，结果都很好。然后我使用rsync将项目目录发送到正在VM中运行的FreeBSD。在那里我做了，但是当我运行时，它找不到main。这是一些类路径的东西-我需要在VM机器上的JDK中进行配置吗？

hk222su@freebsd-vm-group25:/home/hk222su % ls
groupAssignment1    Program.class       Program.java        Received
hk222su@freebsd-vm-group25:/home/hk222su % rm Program.class Program.java 
hk222su@freebsd-vm-group25:/home/hk222su % ls
groupAssignment1    Received
hk222su@freebsd-vm-group25:/home/hk222su % cd groupAssignment1 
hk222su@freebsd-vm-group25:/home/hk222su/groupAssignment1 % ls
1dv512_group25_assignment1.iml  out             screenshots         some_notes          src
hk222su@freebsd-vm-group25:/home/hk222su/groupAssignment1 % cd src
hk222su@freebsd-vm-group25:/home/hk222su/groupAssignment1/src % ls
Program.class   Program.java
hk222su@freebsd-vm-group25:/home/hk222su/groupAssignment1/src % javac Program.java 
hk222su@freebsd-vm-group25:/home/hk222su/groupAssignment1/src % java Program.java
Error: Could not find or load main class Program.java
hk222su@freebsd-vm-group25:/home/hk222su/groupAssignment1/src % java Program.java
Error: Could not find or load main class Program.java
hk222su@freebsd-vm-group25:/home/hk222su/groupAssignment1/src % javac Program.java
hk222su@freebsd-vm-group25:/home/hk222su/groupAssignment1/src % java Program.java 
Error: Could not find or load main class Program.java
hk222su@freebsd-vm-group25:/home/hk222su/groupAssignment1/src %