Java
USING THE DOS COMMAND PROMPT

GETTING TO THE DOS

DOS, the old operating system that the first versions of Windows relied upon, can still be accessed in newer versions of Windows. It is not really called DOS anymore, but rather simply the command prompt.

To access it, simply go in the START menu, pick RUN and type in cmd and hit Enter. This will bring up your DOS window.

In newer versions of Windows, as soon as you hit START, you have a text field that immediately appears and you can type cmd in there (see below).

Doing so will bring you to a window that looks like this:

NAVIGATING IN DOS

PART 1 – THE cd.. COMMAND

In the window above, you get a listing of the folder (also known as directory) that you are currently in. Above, you see that you are on the C drive, then inside the Users folder, and then inside the Administrator folder.

We can go up one level by using the cd.. command. Using the command twice will bring us to the C drive (See below).

PART 2 – THE dir COMMAND

To see a listing of files and subfolders that are in the current folder, you simply type in dir.

In the listing above, you see the file names and folders on the right hand side. The <DIR> specifies that those are folders (directories).

PART 3 – THE cd dirName COMMAND

We can go into a subfolder by also using the cd command. In this case, we simply add the folder’s name.

For example, in the listing above, you see the folder Python24 folder. To go inside that folder, we use: cd Python24

With these commands, you should now be able to go to any folder on any drive on your computer.

GOING TO JAVA’S FOLDER

We need to go to the folder that contains Java. To do this, we use the following commands:

cd C:\ <hit enter>

cd Program Files <hit enter>

cd Java <hit enter>

We can now see what is inside this folder using the dir command.

You can see that there one folder with JDK1.7 and three different folders with JRE software. This will vary on different computers.

To run a program, we will go inside the JDK folder. We have to type that exactly.

cd jdk1.7.0_13

We now want to go inside the bin folder.

cd bin

We are now in the folder that contains both the java compiler and the java interpreter! Woo hoo!

LOCATING/CREATING YOUR JAVA FILE

OPTION 1
You need to write the source code for a program and copy that file to this same folder.

OPTION 2
Type in the following:

notepad Test.java

In Notepad, type your program. Make sure the class name matches the file name. Save it.

COMPILING YOUR FILE

Simply type javac Test.java

RUNNING YOUR APPLICATION

Simply type java Test

In the example above, the filename is called PATTEST.java