Compiling and running java packages from a command line

To compile the above example, you must be outside the packagetest directory. To compile the classes:

   javac packagetest/ClassB.java
  javac packagetest/ClassA.java

To run the main program in ClassA.

   java packagetest.ClassA

or

   java packagetest/ClassA

In windows the "/" can be replaced by the "\" in the javac command, but not in the java command. Generally use a forward slash ("/") because it is used more commonly than the backslash in other places as well.