Im able to run exe's in runtime via Runtime.getRuntime().exec(filePath), but this only seems to work for external exe's outside of the jar. I want to run an exe that I've packaged inside of the jar. How would I do this? I'd believe theres a jar load function, because I've seen code that loads it the same way using the name of the file in the jar, but that returns an IO error for me.
You can copy it to a temporary location outside the jar file, I think that is possible.
Related
I want to run a fat client delivered as a Java web start application without Java web start. I launched it via javaws and managed to get all the jar files mentioned in the JNLP file from the cache after they were downloaded.
I tried running the jar file that contains the main class according to the JNLP file, but I get the 'Could not find or load main class' error. Were I just trying to run a class I'd set the classpath accordingly, but since I'm running a jar file with java -jar, as far as I know the classpath settings will be ignored anyway. Now I'm not sure what to do, does anybody know how to tackle this?
I'll answer this myself now, turns out it is stupidly simple: Get all the jar files, unzip them to get the content, merge all the content (best done with rsync), create a new MANIFEST.MF file that contains the main class to be loaded and the merged hashes for all existing files from all MANIFEST.MF files, zip again to create a jar. That's it.
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).
Uploaded a jar file from my computer to a server and tried to run it. When I run it I get java.lang.NoClassDefFoundError and it seems to be related to the twitter4j jar that my main method depends on.
However, I have this jar file in my libraries so shouldn't this be included when I build my code in to a jar? Here's a pic in case it helps.
is the error that I'm getting. (can't upload a pic just yet.
Not sure what this has to do with twitter, but anyway, the issue is that you do not have the correct class files. In other words, when you are running your fat JAR in the command prompt, you do not have any libraries exported with it (Or if you do, you don't have that specific one).
Sometimes such an error can be because there is an incorrect version of java, however that is not the case here since java has got no "twitter" packages or classes in it.
Using something like JarSplice would fix this.
Assuming you did not package the twitter4j classes inside your application jar, you need to tell Java where it can look for classes that are not inside your application jar. You typically use the classpath flag for that. In your case, it should look something like
java -cp /tmp/twitter4j.jar -jar /tmp/myapp.jar
An alternative would be to package all twitter4j's classes inside your application jar. This is called a 'fat' jar. How to make one depends on how you build your application jar.
The JAR file that you are trying to use needs to be in the classpath. This can be done by using the -cp attribute from the command line. However, when using java -jar, you cannot use the -cp attribute.
To get around this, you can do the following:
java -cp /tmp/myapp.jar;\path\to\external.jar com.example.package.MyClass
where MyClass has the main() method defined.
Alternately, you can specify jar files on the classpath using the manifest.mf file. See http://docs.oracle.com/javase/tutorial/deployment/jar/manifestindex.html for details.
In eclipse I have a java project that runs an external program (a .exe) from the main method. This program is in a folder ext under the rot of the project on the same level as the source folder. Now when I run this program from Eclipse it works Like a charm. But when I export a jar file, it does not. I end up with a jar file that does contain the ext folder, but I still get a FileNotFoundException.
I did think of using getClass.getResource('path'), but I can't use this from the static main method.
Any ideas?
To get around the static issue, you can use ClassLoader.getSystemClassLoader().getResource('path')
This may or may not work depending on how you are launching your .exe (it doesn't really have a file path now, since it is inside the .jar, and I'm guessing it won't) - having a .exe inside a .jar seems odd to me. Why not leave it outside the .jar, and specify its location with a configuration parameter? This would make much more sense.
Try
Foo.class.getResource("...");
I would like to ship my application as a self-contained jar file. The jar file should contain all the class files, as well as two shared libraries. One of these shared libraries is written for the JNI and is essentially an indirection to the other one (which is 100% C).
I have first tried running my jar file without the libraries, but having them accessible through the LD_LIBRARY_PATH environment variable. That worked fine.
I then put the JNI library into the jar file. I have read about loading libraries from jar files by copying them first to some temporary directory, and that worked well for me (note that the 100% C library was, I suppose, loaded as before).
Now I want to put both libraries into the jar, but I don't understand how I can make sure that they will both be loaded. Sure I can copy them both to a temporary directory, but when I load the "indirection" one, it always gives me:
java.lang.UnsatisfiedLinkError: /tmp/.../libindirect.so: /libpure.so: cannot open shared object file: No such file or directory
I've tried to force the JVM to load the "100% C" library first by explicitely calling System.load(...) on its temporary file, but that didn't work better. I suspect the system is looking for it when resolving the links in libindirect.so but doesn't care about what the JVM loaded.
Can anyone help me on that one?
Thanks
One way would be to spawn another Java process from the first, generating the appropriate invocation script.
The jar is invoked by the user
The libraries are extracted to a temp directory
A (bash) script is written to the temp directory
this sets/exports the necessary environment variables
this launches the second JRE instance
The code makes the script executable
The code invokes the script
I know, spawning two JRE instances to launch one app would not be my first choice either.
If you are using Eclipse IDE, then this answer might help you.
I had same problem in eclipse windows that I couldn't added dependant .class files from the JNI.
After searching for a while I came to know that "Its a known bug inside Eclipse", In order resolve the same, I ported all the code to NetBeans IDE.
Can not add all the classes files from the JNI folder in Eclipse (JAVA, Windows 7)