Question

I am trying to develop a Java applet for scientific purposes. I am working in Eclipse, on Ubuntu 11.04; since I needed some additional features, I included the libraries “flanagan.jar”, “jcommons.jar” and “jfreechart.jar”. Now, when I run the applet from inside Eclipse everything goes fine. When I try to do so OUTSIDE of Eclipse, however, not quite. To say a few examples:

1) if I try to run it by embedding it into an HTML file with or tags, the applet fails and I get an error because the definitions for the classes taken from the libraries are missing, even though I placed them in the same folder and used the proper archive value to tell the browser where to look for them;

2) if I try to compile the applet with javac, by inserting:

javac -classpath sourcefile.java library1.jar library2.jar

I get an error saying that the class names for the .jar files are only accepted if annotation processing is explicitly requested.

3) I can find no way to produce a single output .jar file embedding all the required library files. I also think it would be neat if I could avoid embedding the entire libraries (they weigh something around ~4 MB) and actually use only the .class files I really need. I don’t know how to do however. Could you give me some suggestion on how to do one of the three things above?

Answer 1

You need to place your jar list immediately after the -classpath argument using a colon : demilited list:

javac -classpath library1.jar:library2.jar sourcefile.java 

You could use Eclipse to produce a single output jar by using:

Export...->Java->Runnable JAR File->Next->Copy required libraries into a sub-folder next to the generated JAR.

Then you can either jar up the content of the new jar file sub-folder or use:

javac -classpath sub_folder/*.jar sourcefile.java