Develop Reference

Create Java projects without eclipse?

Is there any way I can create Java projects using a simple text editor? Not an IDE like eclipse?
I want to be able to create .jar files without the assistance of an IDE, I have all the JDK commands installed already on my computer (such as javac)
I'd like to know what file structure I need, how I need to arrange my class files, what compilation steps I need to go through etc. to be able to create jar files.

Yes, completely doable (just not much fun once the project gets bigger).
I suggest if it's not a throwaway project, use a build tool like Maven or Gradle to manage your build process, so that you don't need to assemble classpaths and resources yourself, but still retain full control of the build and test lifecycle, without IDEs. This comes at a complexity cost, of course, but once it's set up life becomes easier.
See also How can I create an executable JAR with dependencies using Maven? or the Gradle docs about creating JARs
I'd highly recommend the standard Maven source directory layout too (src/main, src/test etc) as it's both commonplace and makes for easy integration with the above tools.

Follow the below steps to create a jar file
Compile the java source using javac
Create a manifest file (if main exists) to identify main class
Use the below command to create a jar file
jar -cvfm *.class

Yeah. You can create your project structure without an IDE. But it's time consuming and you have to do everything.
To talk about creating JAR, you don't want any extra software. You can use jar utility, which comes with JDK.
Here are steps to create jar:
Compile classes which you want to in jar
Create manifest file (.mf). It's needed if you want to make jar as executable. If you want to bundle classes only together, then no need. (eg. Dependency jar)
Go to command prompt and execute following command "jar cvf MyJarName.jar *.class". Make sure java is set in environment path and you're inside the directory of classes.
cvf means "create a jar; show verbose output; specify the output jar file name.
That's all. If you want to include any folders inside jar then you can use folder name in above command after classes and it must be separated by space.
Example: jar cvf TicTacToe.jar TicTacToe.class audio images

Creating a .exe for a java project

I've developped a game during a Game Jam and I'd like to create an executable to distribute it to the other team members.
The game uses the slick2d and lwjgl library. I've tried to use JExePack, but the .exe file I get isn't runnable, I get an error while launching it.
Even the jar file gets me errors.
I'm only able to launch the game on the IDE. When I launch it with the command line : java -jar "game.jar", it obviously tells me that there's missing libraries, even if I indicate the path to the lib folder.
Is there an easy way to create an executable ?
Thanks in advance.

I think using a jar was a good idea.
You need to add every required jar in the classpath one-by-one for the jar to run properly.

Launch4J (http://launch4j.sourceforge.net/) is my favorite tool for that. You can just export an executable jar from your IDE and create an exe out of it. Creating an executable jar in Eclipse gives you the option to include all required libraries in it, which saves you from adding them manually when create the exe file. The minimal settings you need are:
Input (your executable jar)
Output (the .exe you want to create)
Minimum Java version (i.e. 1.6.0)
Thats it (as far as I remember)

If you want the exe you can use exe4j, it's a very useful tool, but i think using jars is better since you can run them on every platform. Anyway, when you export the jar, check on your ide's preferences if it automatically imports the libs. (for example, on eclipse you can pack the required libs into the exported jar)

You can use Luncher4j to create an exe file and convert the jar libraries to dll files.

Creating a jar file to be run on any other machine

I have to create a jar file wherein i need to add external jar files in the classpath, properties files, in such away as to run it on any other machine.

You could either use manifest.mf to define external class path or use script that composes classpath and runs your application.

I really recommend you to use a build tool such as Maven for these things:
http://maven.apache.org/
How can I create an executable JAR with dependencies using Maven?
Regards,
Boskop

You can make the jar in almost any IDE. I agree with Michael SchmeiBer, be a bit more specific please.
I use eclipse as my IDE (because you can both use it in windows and Ubuntu Linux) to make a jar (you can define the startup class in the jar).
I use different methods for starting up of different machines.
I use nsis to create a nice windows executable (.exe) You can include your own icon.
In nsis script you actually use the same command you would use in a batch command.
nsis has some nice features, like search for a java jre.
For Linux and Mac I use a .sh file with this command.

Java DB Derby and Netbeans 7.1 Build Problems

My application accesses a Derby Database and I have added the Derby.jar to the libraries in the project. It runs fine when compiled and runs perfectly inside the Netbeans environment but once I Build the project, only my application.jar file is in the dist folder. The program will still run but once I try doing anything with the database it hangs.
I tried adding the lib folder containing Derby.jar to the home directory of the application.jar but I still get the same problem.
I'm new to Derby and I'm confused by this, any suggestions?

The answer 1 above does not address the fact the you need to first connect to the database in the service tab of the IDE before you can run your application and that is not possible when you run your application outside the IDE.

This is because you don't also add the project external jar dependencies (such as Derby's jar) to the classpath of your project's executable jar. Basicly, try following their tutorial here:
http://netbeans.org/kb/articles/javase-deploy.html#Exercise_1
the chapter entitled "Running the Application Outside of the IDE" and the one after that.
I haven't used Netbeans in a long while so I don't know if they added this functionality to it now, but with Eclipse you can also make a "fat" executable jar, where all the external jars are packed inside that executable jar, and Eclipse adds a special classloader which makes all this work. It's the option called "Package required libraries into generated jar". Maybe Netbeans lets you do that now too, via some export function or something similar.

Application compiles and builds on Netbeans but not as an independent jar file?

Is it possible that your application compiles and builds flawlessly in Netbeans but when you build it and run it outside of Netbeans you get heaps of Exceptions??! (keeping in mind that the all the libraries and dependencies are ported along with the actual jar file).
I run the followng command
ant -f run
and my program runs flawlessly as it's supposed to, however, where I run the following command to actually build a jar file,
ant -f jar
and when I run the jar file, my application runs but does not perform the tasks it does when it is launched using the first command.
Any ideas why this is happening??! I'm totally lost with this behaviour and can't find why!

If the exceptions are ClassNotFound, then it means that you're missing JARs in the CLASSPATH. NetBeans is sorting it out for you, but when you run outside of it you have to manage it yourself.
keeping in mind that the all the libraries and dependencies are ported
along with the actual jar file
I'm not sure what the word "ported" ends up looking like for you, and without any real information I'm guessing, but your app isn't packaged correctly.

How are you attempting to build your project outside of NetBeans?
Inside NetBeans, if you created the project from within NetBeans, I believe that most of the time NetBeans will create all of its (by default) Ant targets in a file called nbbuild.xml.
Thus, if you're attempting to compile your project outside NetBeans from the command-line (however it exists on your system), you would then need to use the -f nbbuild.xml argument to the ant program to use the NetBeans-generated Ant file. So your command-line might look like this:
ant -f nbbuild.xml compile
Substitute, of course, the target you desire to run for compile in the example above.