This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
The Java virtual machine (JVM) employs a class loader to load classes used by an application on an as-needed basis. The CLASSPATH environment variable tells the class loader where to find third-party and user-defined classes. You can also specify the classpath on a per-application basis with the -classpath JVM command-line argument, which overrides the classpath specified in the CLASSPATH environment variable. Classpath entries can be directories that contain class files for classes not in a package, the package root directory for classes in a package, or archive files (such as .zip or .jar files) that contain classes. Classpath entries are colon-separated on Unix-type systems and semicolon-separated on MS Windows systems. http://java.sun.com/j2se/1.3/docs/tooldocs/win32/classpath.html When you type a command into the shell, it has to find the program on your hard disk before executing it. If the shell had to look all over the disk, it would be very slow; instead, it looks in a list of directories contained in the PATH environment variable. This list of directories makes up the shell's search path; when you enter a command, it goes through each one in turn looking for the program you asked to run. http://www.panix.com/help/path.html