How To Make An Executable JAR File In NetBeans 3.6 (NetBeans is an industrial strength Java IDE found at

Transcription

1 How To Make An Executable JAR File In NetBeans 3.6 (NetBeans is an industrial strength Java IDE found at Directions & Screen Shots by David Yeung. Wordsmithing by Gerry Donaldson. Date of This Revision: May 31, 2004 Java was conceived as a language that would allow developers to write once, run everywhere. The tremendous cost savings of this strategy over having to twig, configure and recompile new machine language files for every platform are tremendous. The tradeoff, in Java s case, is that Java programs typically run significantly slower because an interpreter program (java.exe) is used to translate JVM (Java Virtual Machine) machine language to native machine language during execution of a program. A second major disadvantage is that Java does not allow for automatically launching executable files such as those generated by native machine language compilers, thus obviating the need of the user to know anything more about the system than clicking an icon. The Java executable JAR file addresses the user s need to launch a Java application by simply clicking an icon. In order for executable JAR files to automatically execute outside of NetBeans, it is necessary that the operating system have previously associated the javaw.exe file with the.jar extension. To do that in Windows 2000, for example, check out the following web site Locate your Source Code: Example Hello World (See below.) package HelloWorld; import javax.swing.*; public class Hello { public Hello() { JOptionPane.showMessageDialog( null, "Hello World!"); } public static void main(string[] args) { Hello hello = new Hello(); System.exit(0); } } 2. Launch NetBeans 3.6. Mount the source code directories appropriately for use in NetBeans.

2 3. Right click name of folder containing the source code. > Click New > Select & Left Click All Templates... How To Make An Executable JAR File In NetBeans 3.6 Page 2 of 8

3 4. The New Wizard screen appears. Click the + sign beside JAR Archives > Select JAR Recipe. The screen should appears as follows. 5. Click the Next button. Give a name to the JAR Recipe file. In our example we will call that file Hello. The screen should appears as follows. How To Make An Executable JAR File In NetBeans 3.6 Page 3 of 8

4 6. Click Next. > A screen appears as follows. Note that the JAR file will be saved in the same directory as the file containing the source code. 7. Click on Next>. > Now navigate to the source code folder by clicking the + sign beside the Documents and Settings folder in this case. > The following screen appears. How To Make An Executable JAR File In NetBeans 3.6 Page 4 of 8

5 8. Select the source code folder ( HelloWorld in this case.) > Left mouse click the ADD> button. > Click the Next> button. > The following screen should appear. 9. Click the Next> button. The screen should appear as follows. How To Make An Executable JAR File In NetBeans 3.6 Page 5 of 8

6 10. Press the Generate button in order to generate the manifest text which will launch the JAR file. > Add the line Main-Class: followed by the path of the class name. ( HelloWorld.Hello in this case.) > The screen appears as follows. The background shows the directory structure containing the HelloWorld files. How To Make An Executable JAR File In NetBeans 3.6 Page 6 of 8

7 11. Left mouse click the Finish button. > A JAR Recipe file should appear in the folder containing the source code. > Right mouse click the JAR Recipe file. A screen should appears as follows. 12. Select and left mouse click the Compile menu item. The menu window then disappears while NetBeans compiles the code. > Right mouse click and select Execute which executes the executable JAR file. A screen similar to the following should appear. How To Make An Executable JAR File In NetBeans 3.6 Page 7 of 8

8 Note 1: The JAR file executes only if the operating system knows the location of Java s javaw.exe file. The executable JAR file automatically executes within NetBeans because NetBeans knows where the javaw.exe (java interpreter for windows) file is. In order for the executable JAR files to automatically execute outside of NetBeans, it is necessary that the operating system have previously associated the javaw.exe file with the.jar extension. To do that in Windows 2000, for example, check out the following web site. Note 2: Note 3: Note 4: It is always necessary that class(es) be organized as a package. This occurs automatically when the code is written in NetBeans, but the package statement must be added to source code created in most editors and IDEs outside of NetBeans. Do NOT place any unrelated source code files in the source code directory(ies). If JAR files have been correctly associated with JAVA s javaw.exe file, then clicking the executable JAR file will now automatically launch the Java application. How To Make An Executable JAR File In NetBeans 3.6 Page 8 of 8