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Running Java Applications
Some java software may be run as a stand-alone application outside of
a web browser. This requires the JavaTM 2 SDK Tools which come with
the JavaTM 2 Runtime Environment (JRE) software. In particular, you'll need
A Brief How-To This page will briefly explain how to launch a java application on a Windows system. It is assumed that the java application is a jar archive file residing in a local directory on your system whose name ends with .jar. If you can find a command prompt and navigate to the directory containing the jar file named "SomeJavaApp.jar", you can typejava -jar SomeJavaApp.jar to launch the app. Otherwise read on. The Easy Way Windows may already know it should open jar files with the application launcher.
If so, you can double-click the jar archive file to launch it as you would any
other program. Otherwise, double-clicking the jar file should bring up an "Open With" window
with a checkbox that says "Always use this program to open this file" - all you need
to do is locate the "java.exe" file (the launcher) and select it (select the
"javaw.exe" file to run java with no console window). If you don't see the launcher
listed in the "Open With" window, you can use the "Other..." button to browse around
and find it. The surest place to look is in the "bin" directory of your JRE installation,
although there might also be a copy of the file in the Windows directory.
Usually the path to the launcher resembles Command Line Intro
This section refers to the use of the command line to type in commands.
If this is unfamailiar to you, look up "command prompt" in Windows help
and read this introduction. To run a program, you type the name of the program on the
command line and hit Enter. For example, you could type in "java.exe" to run the
application launcher. Some programs accept an additional file name on the command line. For
example, the app launcher can be run with java.exe SomeJavaClass to launch a java program named SomeJavaClass. In fact, you can drop the ".exe" from the command : java SomeJavaClass will work the same. Where do you enter commands? Under the Start button there is a "Run" item which brings up a window which allows you to enter commands. A better place to enter commands is at a command prompt. Check Windows Help to locate and launch the command prompt window. The command prompt window is often called a console window. It displays the current drive and directory and you can type in commands such as "dir" to list the directory's contents. Other commands allow you to change directories and navigate around your system. Read the help entries on the MS-DOS commands to learn more. Running the Application Launcher from the Command Line
If you enter "java" on the command line, you can get a help message describing
the usage of the java application launcher. Try entering the following on the
command line : java -version You should see a message concerning the JRE version unless the system can't find the launcher (java.exe). If you get a "Bad command or file name" message, you'll need to add the location of the launcher to your system's PATH, a topic which is beyond the scope of this explanation. If you know where the launcher is, you can put the full path on the command line (enclose commands in quotes if there are blank spaces): "C:\Program Files\Java\j2re1.4.2_03\bin\java" -version Note : Replace the typical path above with your actual path to the launcher. Hint : the Windows directory is always in the PATH, so if you place a copy of the launcher file there, you can omit the path and just type in "java".
Assuming you can successfully run the app launcher from the command line,
locate the .jar archive file. You will need to type in its full path
on the command line. Say the jar file is named "SomeJavaApp.jar" and
it is located in the directory "C:\javastuff\". You would launch it by entering the following
command :
java -jar -cp C:\javastuff C:\javastuff\SomeJavaApp.jar The "-jar" and "-cp" items tell the app launcher that the java program is a jar file and that the paths to it are included in the command. As mentioned above, you might need to include the entire path to the app launcher: "C:\Program Files\Java\j2re1.4.2_03\bin\java" -jar -cp C:\javastuff C:\javastuff\SomeJavaApp.jar Using a Command Prompt console window to enter your commands allows you to see any error messages as well as other messages generated by the java program. Why Would Anyone Type All This on a Command Line ?
Instead of using the "-cp" option, which requires putting the path on the command line,
you can navigate to the directory containing the jar archive file and then type
java -jar SomeJavaApp.jar to launch the SomeJavaApp.jar file as an application. To navigate, use the "cd" or "chdir" (stands for change directory) DOS command.
Here is an example which uses the "cd" command to change directories : cd \ and hit enter. The backslash after "cd" changes directories to the root directory. From there you can change directories to the one with the jar file by typing something like cd javastuff or cd javastuff\somedirectory\somesubdirectory and then view the contents of the directory by typing dir /p If you see the jar file listed, you can type java -jar SomeJavaApp.jar to launch SomeJavaApp.jar. One Last Bit The DOS "exit" command will close the command prompt window. |