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Keeping history of items without using a database in java

I have a small java utility application which performs tasks on remote computers. This app will provide user with a dropdown/combobox where they can enter ip address or hostnames for the computers they wish to connect to. It would be nice if the users could have a history of items/hosts they had connected in the dropdown.
I thought that I can create a file inside the distributable jar and use it to maintain the history. But writing to a file inside the jar seems to be impossible? The alternate approaches would be to use text files, databases etc located outside the jar. But this is not quite I would like to do as my utility app is only one file and I would like it to be completely independent of any external files. Also its not nice to have a text file stick around your jar file or create a text file each time your app is run.
Considering this case what options can I use? Are there any apis that can help in storing or keeping history?

Why don't you store this info with an hidden file in the user home directory? Many application do the same thing.
You can get the user home directory in this way
String userhome = System.getProperty("user.home");

I'd recommend keeping some .dat file somewhere associated with the JAR. Could be in same directory, or in the user's home (as #dash1e recommends) to avoid any permissions issues. I think you'll find that's the simplest solution.
Another option would be to use a Java-based database solution which could be bundled into your JAR (see Apache Derby, et al). Note that this would create files somewhere, but you wouldn't have to worry about the file-level management, as you'd just be interacting with it as a database.
One final option, if you really insist on avoiding having to maintain your own file, would be to use the Java Preferences API which provides an OS-agnostic way of storing data on the system in some obfuscated location. This is arguably a bit of a misuse of the goal of this API, but would accomplish what you're asking for.

Common place for creating files on various platforms (non-user-specific)

I write cross-platform java app and I need some place where I can store some amount of files. These files will be used by another java application that may run under another user. This mean that I cannot use:
System.getProperty("user.home");
since I may have no permissions to read/write these files. What I need is some way to get non-user-specific folder where every app can create/read/delete files (something like "C:\ProgramData" for windows).
Is there a cross-platform way to get such folder(at least for Windows and Linux), or if there is no any - what is the best way to get such folders for Windows(should work on XP-7), Linux and Android.
Any pieces of puzzle are welcomed.

I'm not aware of such such a cross-platform folder which is additionally readable by all users. But you can:
Define a specific folder for each OS, commons-lang may help you determining the platform (see SystemUtils)
Check if the folder read/writeable for the current user during application start-up.
Using a central configuration (where the data exchange folder is defined for this installation) may also be an option, but this depends on the packaging of your project.

Java - where to put application data?

I'm writing a Java application which requires a number of resource files (there will be about 100 files of 20-40K each). They are not edited by the user, but will require periodic updates (the application will have a function to check for changes to the resource files and download them). Ideally, the application should be cross-platform.
Allowing write access to a subdirectory of the program directory is generally frowned upon. If I was doing it as a Windows application I might put them in Application Data, but that's not going to fly cross-platform. What would be the best place to put them?

I would typically create a directory (name starting with a period ".") in user's home directory (System.getProperty("user.home") if I am not mistaken) and use that for application specific storage. Alternatively, you could take the directory name from user at the time of application installation.

Have a directory you use to keep these files in. Put that information in a properties configuration file. When you start up load the configuration file from your application install directory. From that properties file it tells you where to find your file directory. When your installer runs it can write out this configuration file for the platform you are installing on, and that can be OS specific.

Provide a configurable location, but default to a directory in the user's home directory, or in an OS-specific location.
You'll have to deal with this in a platform-specific way no matter what. You have a few options under OS X, though. For unix-like systems either a home directory, or perhaps something under /var.
That said, I don't believe a program managing its own data in its own directory is a bad thing; consider a program with an embedded database or similar. It's much more reliable to use an app home directory.

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?