Classpath

Question

Good evening,
I've searched a lot about this issue and tried several things, but still couldn't get to a solution. I've coded my program with BlueJ. From BlueJ, it runs perfectly, but when I try to run it from the command prompt, I'm getting the error "Exception in thread "main" java.lang.NoClassDefFoundError: gate/LanguageResource.
The classes for my program are stored in C:\JavaClasses but the jar files required by my code reside in C:\gateApp and C:\gateApp\plugins. In fact, I have this piece of code in the main method:
{code}
// initialising the GATE library
Out.prln("Initialising GATE...");
String applicationPath = "C:/gateApp/";
File gateHome = new File(applicationPath);
// setting parameters
Gate.setGateHome(gateHome);
System.setProperty("gate.user.session", gateHome.getPath());
// setting plugins home
Gate.setPluginsHome(new File(applicationPath + "/plugins"));
// setting configuration file
Gate.setUserConfigFile(new File(gateHome, "user-gate.xml"));
Gate.setSiteConfigFile(new File(applicationPath + "gate.xml"));
Gate.init();
Gate.getCreoleRegister().registerDirectories(gateHome.toURL());
Gate.getCreoleRegister().registerDirectories(new File(applicationPath + "plugins/ANNIE").toURL());
{code}
Can you help me with this problem in simple steps please since I'm a bit of a beginner?
Thanks for your help!

Answer 1

alley wrote:
May I just ask you one more question please? The rules for my project state that the code should be run from a cd by running the command java tempClass from, say, e:\. So if I put all classes and jars into a single folder in the cd, would that be possible to run the command without having to specify the classpaths onto the command line?Strictly speaking yes, but not in a way that you want it to, probably.
An alternative to specifying the classpath on the command line is to specify it in the environment variable CLASSPATH (with the same syntax).
So if you set the environment variable to the value you use on the command line now and then just run "java tempClass", then it would work, but that's probably not what you want to do.
To produce programs that need no "-cp" switches and no "CLASSPATH" environment variables, you'd have to produce a .jar file. A .jar file is an archive containing all your classes and some meta-data. That meta-data (found in the manifest file) can include a "Class-Path" attribute which points to other resources necessary to run that program (i.e. to other jar files, usually).
When you did this (google is your friend for info on how to do it), then you can run it with a simple "java -jar myApp.jar"