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Use database in embedded-server mode outside the `$objectdb` home directory

I'm trying to setup ObjectDB. I am able to create a database and view it with the explorer, using the embedded-server mode to be able to keep the explorer open while running my program. This all works fine, when my database is in the $objectdb/db/ directory.
However, I'd like to be able to do this when my database is in another directory (thus not in $objectdb/db/). When I'm not using the explorer, the database looks fine. I can also open the explorer to view the database. But... I can not keep the connection to my database open in the explorer while running my program (and thus making changes to the database).
What I have tried/have been thinking about:
The database and the explorer have to use the same .conf file. I think the explorer uses the conf file in the $objectdb home directory, but I can't figure out how to configure my database in the other directory to listen to that conf file, too. How can I create a project (or database) specific conf file for a database that's not in the $objectdb home directory?
In general it feels strange to me that there would be one conf file for all your ObjectDB databases.
I copied both the explorer.exe and objectdb.conf to the directory my database is in, hoping this would work. However, nothing happens when I try to run the exe file. I think this is because the exe (and the explorer.jar, tried that one, too) rely on objectdb.jar, but I couldn't find that anywhere. I found objectdb-2.7.1_01.jar and copied that into the directory the database and explorer were in, but that didn't help.
As for an MWE, I followed this tutorial, using IntelliJ.

Try the following:
Open the database in embedded mode with a path that specifies a free port for the embedded server, e.g. "$objectdb/db/my.odb;port=9999"
Access this database in client mode using "objectdb://localhost:9999", or in the Explorer, select File -> Open C/S Connection, specify 9999 as the port and keep the database path empty or /
objectdb.jar is available when you download ObjectDB as a zip file (in which you also find the Explorer), you can also rename the file from Maven, which contains a version number to objectdb.jar.

Do we need seperate file path for window and linux in java

I have a file on linux ubuntu server hosted with path name /home/kishor/project/detail/.
When I made a web app in window to upload and download file from specified location i used path "c:\kishor\projects\detail\" for saving in window.
For my surprise when i used window file path name in my server i am still able to get files and upload them, i.e, "c:\kishor\projects\detail\".
Can anyone explain why it is working (as window and linux both use different file path pattern).

I've seen this work too. What linux does is create a file whose name is literally c:\kishor\projects\detail\

If you say, you can "upload" files... perhaps there is now a new folder structure.
Some months ago i saw a similar thing: Under /home/webadmin was an new structure "/c:/Users/...."

Locating created file with Java EE and Tomcat

I have created a dynamic web project, and use Apache Tomcat as a server.
In my servlet I'm creating a text file and want to reuse that in a JSP. However they are by default created in the installation folder of Eclipse when I do something as simple as the following:
File f = new file("test.txt").
I don't know why this happens. Is there a way to create the file in the WebContent directory as I want to make that file available for download in my JSP.

Java has a concept of the "current directory". When you start an application via Eclipse, this may indeed point to your installation directory. If you don't specify any path, a file will be created in this current directory. Hence the reason why your test.txt ends up there.
The WebContent directory is a something that is specific to Eclipse. Your code should not depend on putting anything there. You only start your application via Eclipse when you're developing it, not when you're deploying it to a live server.
The content of this directory will become the root of your .war, which is a well known location independent of how you start & deploy you app, BUT you still cannot depend on writing anything to this location at run-time. You might deploy your application as a packaged .war (likely for live deployments) or you may deploy your application unpackaged but then your application server may simply not pick up any changes done at run-time.
What you can do if you are sure your application only runs on a single server is writing the files to a well known location on your file system, such as /tmp, or /var/yourapp/files, etc. The code serving up those files can then pick them up from that location.
If you want to play it 100% safe according to the Java EE rules, you'd store your files on something like an FTP server that has a configurable address. Technically your war could be shipped between nodes on a cluster and requests could end up going to different machines, so depending on a local filesystem wouldn't work then.

Executing this statement this.getServletContext().getRealPath (""), you'll obtain the path where Tomcat WebServer is pointing at at runtime. You could add a folder "MyFolder" and call this statement:
new File(this.getServletContext().getRealPath ("") + "/MyFolder/test.txt");
Anyway, the default path looks something like:
...\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\<NameOfYourProject>
Note that when you create a new file, it won't appear in your immediate workspace (check the .metadata path), unless you change the runtime location tomcat should point at.

Java on MacOSX: how to access files in the bundle

I have a Java app which I am packaging to a Mac Application Bundle (That folder structure that contains all of the app but looks like a single executable file to the user).
My Problem:
I am reading and writing some config files in the local folder ("."). However, on Mac this seems to be the folder in which the application bundle is located (so usually the "Applications" folder and I obviously don't want that.
My question:
How can I store a file inside that bundle? How can I programmatically retrieve the bundle name to compute the fully qualified folder?
I know I could try to go the ClassLoader way, but I'd like to avoid that (for security reasons).
Or is there simply a better way how to store application cache and config data locally?

The Mac OS X Finder treats any directory whose name ends in .app as an application; right-click to Show Package Contents. It remains an otherwise normal directory for I/O purposes. This project is an example. See this answer regarding paths relative to the application bundle.
Addendum: Is there a better way how to store application cache and config data locally?
The example cited uses java.util.prefs.Preferences, but javax.jnlp.PersistenceService is an alternative.

Ok, the basic answer / solution is: don't do it.
The reason I originally wanted to do it was to cache larger amounts of data on the local HD. Java preferences are a good choice for config data (i.e. small data amounts) but fail to handle data in the megabyte size range.
My solution:
On MacOSX (System.getProperty("os.name").contains("Mac OS X")) I simply create a folder in the user's home folder (System.getProperty("user.home")). I prefix that folder with a . to ensure it is hidden from the user. This also ensures that I have write access to the folder (which could be a problem in the .app folder depending on where the user copies it)
On Windows (System.getProperty("os.name").contains("Windows")) I create that folder in the System.getenv("APPDATA") directory (note that this env variable only exists on Windows systems.
Now I have full access to the filesystem (even without admin rights) and can store as much data as I like.

Java: Where to write config without requiring administrative rights

I actually can't believe I'm saying this but since porting my programs to OSX and getting used to permissions, I've realized that what I planned to do on Windows will not work how I want it to. Currently, on windows, my program stores it's setting's in the registry (HKLM) and some user editable resources in a folder next to the program file. For various reasons, I have now decided that the configuration/settings will be stored in a file and the user will be able to in which folder the other resources are kept.
So the question I have now is where to store the configuration file. Obviously it will be updated, but I don't want to program to have to require administrator permissions to run. I would like to offer an option so that all users can use the program (like most programs do), which will of course require Admin, so this leads be onto the second query: where should I store the configuration file (and the folder in which other resources are kept) and how can I detect whether the program has been installed for all users or just one!
Thanks in advance
PS If you didn't guess, the program is written in Java so I would like to know how to programatically get the location you suggest as well please.

Its normal practice in *nix compatible programs to store information in folders starting with name . in the home directory of the users like,
.bash_history
.bashrc
You could use the same on OSX in my opinion and create a directory say,
.myapp
You can store any number of files with any format under that directory.
To get the location of the folder, you can do
String homeDir = System.getProperty("user.home");
File myAppDir = new File(homeDir, ".myapp");
That is roughly the code that can get you your custom config directory for your app.
Please not that dot files / folders are somewhat similar to hidden folders in windows. Your File Manager will not generally show these files / folders by default.
To identify if the program is installed for all the users or not, you could create the configuration at some administrator (root) controlled location like /etc (not sure about Mac) The user configuration can always override the default config. There could be a better way to handle this though.

On both windows and unix, User(usually) has a (home)folder to which it has full permissions. You may create a directory in the home folder and have your user configuration files reside there.