Develop Reference

JavaFX How to deploy an application and make my resource available in code?

I have written an JavaFX application to study German language with a Flashcard like program. It turned out my classmate also want this but I don't know how to deploy it.
I have a sqlite database which store some german words and I need read/write access. I have tried hardcode the path but it obviously is not good. I have tried to load the sqlite file by the following line and deploy it as a runnable jar but I couldn't write on it.
"jdbc:sqlite::resource:Vokabeln.sqlite"
Assume that I don't want to make remote web application, how should I make this file available to my code, and is platform independent? Should I make a installer program so that I ask the user what is the path? I also don't know how to write an installer application. I googled and didn't find anything like that.

You'll want to distribute your application with the database as a file outside of the Jar because otherwise you won't be able to have write access to it.
If the database file is on the same directory/folder as the Jar file, you should be able to connect to it with a JDBC URL like the following: jdbc:sqlite:sample.db
Distributing your application as a Zip file is fine, but if you can't expect end users to have Java installed and so, there are programs to create installers, even cross-platform, such as IzPack and Install4J

Tomcat cache downloaded files

I use a library that downloads xml files from internet and use it. Sometimes these files are unavailable and to avoid it I would like to cache downloaded files. Is there a possibility to tell Tomcat to cache downloaded xml files and not download these again?

And how should Tomcat even know about the library you're using and this special behaviour you want? Tomcat does not 'download files'. Its your application that is doing it.
Shouldn't you do this yourself when using the library (unless the library already provides this)? I.e. when you get the xml files store them in a folder, and next time you need them you first check the local folder if they exist and if not (or if they're too old) try to get them online, and save them (or overwrite them) with the new files you get.

Your question doesn't make sense. Tomcat is the source. Caching there doesn't accomplish your objective in the slightest. Fortunately the Internet is already full of caches, as is your browser, so your question is already answered by the existing state of things.

Package an application including java war file, Tomcat, DB

i have a java based web application, i have the source code as well as the war file, the application uses mySql and need some web server like tomcat all to be added to some package that can be directly installed on window and linux machines directly..
i need to setup DB, WebServer, and app in one go. Would be great if it can create services for all as well.
is it possible???
i mean the user should just give the location to store and everything should get stored in one go, is it feasible? and if yes please guide me how to do so...

In short: Yes, it is.
Projects like XAMPP are already following that approach. All relevant software components are inside a single ZIP file which you can extract to an arbitrary location on the user's harddisk. All configuration then uses relative paths when referencing files.
So essentially, you will have to put in a little effort in advance to make the "installation" as easy as possible. Maybe you can simply build upon a project like XAMPP and use the infrastructure already provided?

How make working directory files available to WebStart application?

We have to make a Java application demo available on Internet using JWS. It goes pretty well; all that's missing is making working directory files available for the application.
We know about the getResource() way... The problem is that we have different plugins for the same application and each one require different files (and often different versions of the same files) in their working directory to work properly. So we just change the working directory when we want the application to have a different behavior.
Currently, the demo is packaged in a signed jar file and it loads correctly until it requires a file from the working directory. Obviously, the Internet users of this demo don't have the files ready. We need a way to make these files available to the WebStart application (read/write access) in its working directory.
We've thought of some things, like having the application download the files itself when it starts, or package them in the jar and extract them on startup.
Looking for advices and/or new ideas. I'll continue working on this... I'll update if I ever find something reliable.
Thank you very much!

I said I would share what I found in my research for something that would fit my needs. Here's what I have so far.
I have found that the concept of current working directory (CWD) does not really make sense in the context of a Java Web Start (JWS) application. This had for effect that I stopped trying to find the CWD of a JWS and started looking for other options.
I have found that (no, I didn't know that) you can refer (using getResource()) to a file in the root directory of a JAR file by simply adding a '/' in front of its name. ("/log4j.properties", for example.) The impact of this is that I can now take any file which is only referred to in a read-only manner in the root of that JAR file (which is really only a ZIP file). You can refer to any file in the root of the JAR file using AnyClass.class.getResourceAsStream. That rules out the problem with read-only files required to run the application, at the cost of a switch in the code telling whether the application is run from a valid CWD or from a JWS context. (You can very simply set a property in the JNLP file of the JWS application and check if that property is set or not to know where to look for the file.)
For write-only files (log files in my case), I used the property , adding a directory with the name of the application: <user.home>/.appname and added log files to it.
Read/write files (which I don't have in my case) would probably simply go at the same place than write-only files. The software could deal with uploading them somewhere if needed, once modified, I guess.
That's the way I deal with the problem for now.

Note there is a service you can explicitly ask for, to get file access to the computer (unless you go all the way and ask for full access (which requires signed jar files)).
Then you need to determine where these files need to go - basically you have no idea what is where and whether you may actually write anywhere. You can create tmp-files but those go away.
Would a file system abstraction talking to the JNLP-server do so you store the users data on the server?

Having a lot of trouble deploying a java applet

I'm new to Java. I'm simply trying to build a .jar file of my applet so I can run it from my browser. This is what my directory structure looks like:
C:\java\pacman\src
contains all of the .java class files.
C:\java\pacman\assets
contains about 4-5 images and audio files.
If I try to use the following code:
Image someFile=getCodeBase().toString() + "file.png";
The result of getCodeBase() is
file:/C:/java/pacman/bin/
However the following code fails to load:
img=new ImgHelper(getCodeBase().toString() + "assets/");
ImageIO.read(new File(img.getPath("pacman.png")));
Moving my 'assets' folder to the 'bin' folder didn't fix this either. It tries loading:
file:/C:/java/pacman/bin/assets/pacman.png
saying:
Can't read input file!
But the url it gave opens fine if I paste it into run and hit enter:
So to avoid myself a lot of headache i commented out the code in my ImgHelper class and did this:
public ImgHelper(String dir)
{
//this.imgDir=dir;
imgDir="C:\\java\\pacman\\assets\\";
}
Which works perfectly. But I want to put this on a web server, and I have no idea how/what I should do to make all the images and sounds work. Any ideas?
Thanks...

Why not put it all in a JAR file and then call Class.getResourceAsStream?
A JAR file is better as it is a single HTTP connection rather than one HTTP connection per file. It is also much more flexible to use a Stream than a File.
getResourceAsStream will work when the files are not in a JAR as well, they need to be relative to the class file.
EDIT:
Another thing, the File method won't work if the applet is on a server as it will be trying to open the file from the local machine (I think, I haven't tried it) rather then from the server. Even if it tried to create a file path to the server that won't work.

I agree with tofubeer about the JAR, but if you want to put the image on your server, see the tutorial on Applet images here. The codebase will be whatever location your applet is on the server, and you can put images relative to that on the server as well. Use a media tracker along with the Applet.getImage() method to retrive the url. From the example:
my_gif = getImage(getDocumentBase(),"imageExample.gif");

There are two possible solutions that would work:
The images could be present outside the applet JAR. The applet could then be initialized with the location of the directory where the images are present. Once you have that information you could then load images from the server. The Sun Java tutorial provides an example usage of the applet parameter to pass the image source directory.
The applet class loader could be utilized to load the images from the applet's JAR, using the getResourceAsStream() method.
PS: It would be helpful if you referred to the section in the Java tutorials to load icons for your application. The same section discusses a lot of the points brought forth by TofuBeer and John.
EDIT : The usage of the File API is not recommended because it ends up reading off the local file system. That is unacceptable for most users on the internet.