I have written a java program that is actually works as a gui to an existing command line program.
so in basic all my program does is Runtime.getRuntime().exec("myprogram parameter");. So I have exported my java source as a executable-jar file by using Eclipse IDE and it is working nice, however I indeed need to include this myprogram.exe to the directory of the generated jar file inorder to work.
Now I am looking for a way to include myprogram.exe inside the jar file so I can keep it bundled as a single file, a method using using Eclipse would be preferred.
You can simply jar it up as an extra resource (like a .css, .properties etc.).
When your Java program runs, extract the .exe using Class.getResourceAsStream() and write it to a temporary directory in order to run it from there (since you can't run it directly from the .jar file).
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I don't understand how Java jar files work. I am trying to understand what is possible and not possible when creating a Java jar file. Is it possible to have a String path running normally in a Java jar file? Will this normally work as it works when running main class in eclipse? I mean, I have an absolute path in my main class that grabs the file and reads from it.
public static final String file1 = "C:\\Users\\Documents\\test1.txt";
public static final String file2 = "C:\\Users\\Documents\\test2.txt";
This is what I have when running my program and it works fine. This is inside a class that is called somewhere along when I want to read a file. My question is... will this prevent my jar file from working properly normally AS when running the main class from eclipse?
I have the jar file but what if it doesn't or does it still look for file1 and file2?
It doesn't matter whether that code is in a jar file or not. The strings will still be exactly as they are, and if you pass them to methods that look for files with those paths, it'll look for files with those paths in the file system of the machine where the code is running. It won't look for them inside the jar file.
A Jar file is basically an executable of your project, it is used for example by frontend's who need a backend but don't want to open an IDE for compiling and executing purposes. Your Jar file contains .class files responsible for the execution of your project, you an execute your jar in a server too, so your application will run for more people (if you configure right).
I have around 10 java files with their corresponding class files. The whole application works when i execute one of the main class. I execute it using cmd. I need help converting it into a single self executing file. eg: exe or jar
A jar file is little more than just a zip of all classes and resource files. You need to add details into META-INF/MANIFEST.MF file so that the class containing the main method to be executed is know.
This should help: Link
You can try invoking the jar file as follows:
java -cp <jarfile.jar> <Complete.Package.ClassNameWithMainMethod>
You can make jar by Exporting the project using following methods in Eclipse IDE
File->Export->Java->JAR.
Note: This is already have a solution to change to exe or JAR.
How can I convert a .jar to an .exe?
I have an existing Java project that compiles and runs properly through Eclipse. I have created the following .bat file to run the program sans Eclipse:
java -classpath jflashplayer.jar;bin TestProgram
The file is saved within the project folder, but not within the bin folder (located in same directory as bin). When I try to run the batch, I am met with a large number of runtime errors, the first being
Exception in thread "AWT-EventQueue-0" java.lang.NoClassDefFoundError: org/apache/commons/io/FileUtils
I'm not sure why I get this error when it compiles and runs properly via Eclipse. I have the commons-io jar files linked to the project within Eclipse as libraries, and the jar files are themselves located in the project file (same directory as the batch file and the bin folder).
Also, I'm not entirely sure what the -classpath jflashplayer.jar bit of the batch file is doing. I am using the jflashlayer.jar library (also linked to the project within Eclipse and in the same location as the other jar files), but I am not sure why it would appear in the batch file. I edited an existing batch file from a similar project that uses the jflashplayer.jar files, and it has worked previously to leave that part in.
When I write code in Java, I rarely require it to compile/run outside of the IDE, so I usually have troubles when it comes to this part. Perhaps there is a more robust and foolproof method to run the program outside of the IDE other than the batch file method.
The batch file method is fine, but you have to specify all the libraries you're using on the classpath, just like the jflashplayer.jar.
In this case, the error you're getting is because the Apache commons-io library is not specified on the classpath. Your command would have to look something like:
java -classpath jflashplayer.jar;commons-io.jar;<other jars ...>;bin TestProgram
Alternatively, you can create a runnable jar from Eclipse as described here. When you select a library handling strategy, choose the option Extract required libraries into generated JAR. This will make it so that all the library classes you're using are packaged into your application's jar file, and you can just execute it by invoking java -jar my_application.jar.
The Netbeans created Jar does not work, but inside the IDE program it works perfectly.
I believe that the main class is set, so I'm not sure what the problem is, I think it might have something to do with the txt files I'm using, in the IDE they are in C:\Users\J\Documents\NetBeansProjects\PointOfSale\src\pointofsale (the text files are with my java files). After building the dist/ jar though the text files are inside the jar with no folders or anything (Jar is in C:\Users\J\Documents\NetBeansProjects\PointOfSale\dist). I this this might be the problem, if its helpful, I access the files using
File file = new File(System.getProperty("user.dir")+"\\src\\pointofsale\\list.txt");
You need to use Class.getResourceAsStream() to load the file. It searches from inside the classpath (and therefore from inside the jar). Now you can't load the list.txt because it doesn't exist in the directory you're specifying, it's inside your jar.
Something along the lines of
getClass().getResourceAsStream("list.txt"); // Or "/list.txt"
Will give you an InputStream you can use to load the file contents.
I have started getting into game programming.
My question is, that when I am working with files, either parsing data, writing to files, etc. Should I be using relative path names, or absolute pathnames, or something else which is better. I've heard about using jar files, but I am not sure
1. how that works
2. if it is a good way to do it.
So when developing a game that will be cross platform, what is the best method for managing files that the program will need to read from and write to.
there are several ways in which you can ship your code as a product. the most common are
packaging everything in one executable jar file.
having a set of folders where you place all necessary resources.
minecraft, for example, is written in java and distributed as a single executable jar file that contains all necessary class files and resources. to run the game (assuming you have java installed) all you need to do is double-click the jar file.
read this short tutorial about how to add a main class to a jar file.
either way, always treat classes and resources in your code as if they're in your classpath. for example, if you have a my.properties file on the root of the source tree then load it by using 'my.properties'. if you put it under a 'conf' folder then use 'conf/my.properties'.
i think it is the safest way not to get lost.
are you using maven?
The jar file is a zip of all your compiled *.class files and your resources. You can safely load your resources and even default data FROM a jar if you package your program, but you can NOT safely write data back to the jar. This detail is answered in depth already at
How can an app use files inside the JAR for read and write?
For information on how to package a jar see
http://docs.oracle.com/javase/tutorial/deployment/jar/