Managing Connections in a desktop Application or Applet

Wondering how people usually manage connections in a fairly large GUI application (or Applet).
I'm used to using a Connection Pool with Servlets.
Is this worth using with an Application or is it ok to create a Connection at startup and use it throughout the whole execution?
Is it ok then to pass references to this Connection to other classes in the application?
Any tips, experiences, guidelines would be appreciated.
Thanks.
Derek

Hi
I'm assuming that you are using a J2EE Application Server that implements datasource pooling if you have the ability to use Pooled Connection with your servlet (if not, then you must have created your own connection pool?).
Basically, if you have an Applet, then there is no reason to change your current way of working...simply let a servlet in your container handle the database stuff, then return the results to the Applet.
For desktop standalone applications, things are a bit different. You will probably have to implement your own pool. Best practices...hmm...not an expert but I would have thought it best to open the connection, do the SQL stuff, then close it straight away, and in doing so release the connection back to the pool for another application to use (assuming you have a pool). If you are thinking about opening a connection for every application and holding these indefinitely, then you will eventually run into trouble. How many connections can your database handle???
Hope that helps

Similar Messages

How can manage session in javafx desktop application

i have created a javafx desktop application and my application also consume restWebService for login and logout puspose. now how i can maintain session of any particular user??
please if u have any idea let me know??
thanx in advance.

With the setup you have described, you don't need to maintain much of a session like in a traditional browser or a web app server scenario.
WIth a traditional web application, when a login authentication passes, normally a cookie is set in the browser to indicate that a session has been established and is cleared on logout to indicate that the session is over. When the browser client talks to the server it sends the cookie across to the server and the server (using something like the servlet api) decodes the cookie to determine the session and makes use of appropriate session state to access a store of session related data which it eventually just throws away on logout or on session timeout. The cookie is normally a random piece of data which forms a unique id for the session and is normally generated on the server.
If you are using rest apis then they should be coded to be stateless, so there is no session involved, every request to the server is self contained and contains all the information required to authenticate the user. (e.g. the user/password hash is passed every time). Sometimes a variant will be used where a token is passed, for example an oauth token, representing delegated authentication from another service. But you likely don't need to do that and just passing the full auth information everytime is sufficient. The server itself also maintains no state, it just does the auth based on the credentials passed with each request and then performs what ever action it needs to create and return the resource requested.
So really, all you need to do is to:
1. Prompt user for login credentials (user/pass).
2. Hash the pass and make a rest call to the server for validation (http basic auth over https could be used for this).
3. If the auth passes, then store the current user/pass hash as application data somewhere (e.g. members of your application class instance).
4. When you need to make another rest call, query the application instance for the user / pass hash and include that in the call.
5. When the user logs out, clear the user / pass hash from the application (set it to null).
6. Show the login prompt again for the user.
Note that using other communications systems (such as akka, hessian, spring remoting etc), may be a bit simpler for some kinds of JavaFX client/server applications than using REST.

HP Connection manager service not installed. Application will exit

I'm actually having a number of problems with this laptop, but I figured I'd start with this one. I get the message "HP connection manager service not installed. Application will exit.
As strange as this may seem, when I get this message, I also cannot open any of the folders on my desktop. I don't know if the problems are related or not.
Any help is appreicated !
If this helps its model number is A5F92AV

Hi @krazykat_randi ,
Welcome to the HP Forums!
It is a superb place to find answers and suggestions!
For you to have the best experience in the HP forum I would like to direct your attention to the HP Forums Guide Learn How to Post and More
I grasp that you are having multiple issues with your notebook, one of which is when you try to open the connection manager you get the message "HP connection manager service not installed. Application will exit.". You also can not open folders on your desktop.
Have you checked for viruses or malware? MS Malicious Software Removal Tool.
This is not a recommendation but many people have used Malwarebytes with success also.
Have you tried running MS Fix It to aid with overcoming issues?
Have you tried doing a restore back to when it was working properly?
If you still have issues I suggest you do a recovery back to factory.
HP PCs - Performing an HP system recovery (Windows 7)
If you have not yet done a backup you will have an opportunity during the recovery to do one.
HP PCs - Restoring Files that were Backed Up Using HP Recovery Manager (Windows 7)
Hope this helps!
Sparkles1
I work on behalf of HP
Please click “Accept as Solution ” if you feel my post solved your issue, it will help others find the solution.
Click the “Kudos, Thumbs Up" on the bottom right to say “Thanks” for helping!

Problems Connecting Device To Desktop Manager and Apploader.exe

Just got a new BB8900 last Friday. On Monday, I encountered a Reload Software: 552 error code and after checking online forums for options on how to fix I ultimately had to reinstall the operating system and reinstall new apps that weren't archived by the reinstall process. Because I feared getting this error again whenever I rebooted the device, I immediately made backups every hour as I was reconfiguring the device and adding back my apps.
Today I was going to do another backup for good measure and once I connected my Blackberry to the computer with Desktop Manager running, Desktop Manager crashed and gave me the following error:
Problem signature:
Problem Event Name: APPCRASH
Application Name: DesktopMgr.exe
Application Version: 5.0.0.11
Application Timestamp: 4a4bd539
Fault Module Name: DesktopMgr.exe
Fault Module Version: 5.0.0.11
Fault Module Timestamp: 4a4bd539
Exception Code: c0000005
Exception Offset: 000d68f5
OS Version: 6.0.6001.2.1.0.768.3
Locale ID: 1033
Additional Information 1: c4a7
Additional Information 2: 473b2e845affd1758ca8e66121386d63
Additional Information 3: 83e8
Additional Information 4: 72466a8a5092651f7fe609f9ec3f3489
I then tried the APPLOADER.EXE program locating in program files/common files/research in motion/apploader. I had used this program yesterday to try to delete applications 1 by 1 with the hope that one application was causing the 552 error. Now for some reason this program also is having a problem noting the following in the error log file:
Read from location 1010fffc caused an access violation.
I've looked through multiple forums and haven't found a solution. What I can tell you is this:
1) The phone is working fine but I fear rebooting the phone and getting another 552 error (there were two apps deleted that will be fully deleted on reboot). Would hope everything is fine but I've had two of these 552 errors within 24 and the second one came without any warning. If I get this error there is no way to get to my backup since I can't connect to DM without it crashing.
2) It doesn't appear to be a sync issue but I deleted the Intellisync folder anyway and it didn't fix the problem.
3) Have rebooted my machine with no change to problem.
4) Have reinstalled DM Version 5 (this time without the Roxio Media software) with no change to problem.
5) Because I now get an error when connecting to DM and trying to run apploader.exe, there appears to be a setting on my phone that might be causing the problems (I have no idea what it may be but the APPLOADER program notes a location violation so maybe the Blackberry software is confused about where to find my Apps?)
6) The BlackBerry device manager works fine and notes my device and applicable serial number.
After my last backup yesterday I probably only installed 3-4 other apps that I had lost and organized/moved folders around on the phone. So getting this problem so soon after everything was working fine is mindboggling.
Solved!
Go to Solution.

Another Update: I seemed to have found the problem. While RIM support recommended I do a device wipe I pushed back since the rest of the phone functionality seemed to work fine. I opted to begin removing applications from the phone one by one and then trying to connect to Desktop Manager.
Once I removed the ZDNet Tech News For IT Professionals and rebooted the phone, I was able to connect and do a backup. I'm sure this app works fine for almost everyone else, but for some unknown reason (maybe it conflicts with another app on my phone), Desktop Manager did not like it and shut down. I initially reinstalled it again and was able to do another backup but an hour later Desktop Manager shut down again (perhaps in doing an update on news it creates a conflict with Desktop Manager).
Anyways summary of learnings since my issue seemed to be somewhat uniqueCurve 8900)
1) If Desktop Manager shuts down and you've tried other solutions on forums such as deleting the Intellisync folder and reinstalling Desktop Manager, try deleting applications 1 by 1 and rebooting the phone before trying to connect again to Desktop Manager.
2) If you have had this problem, do frequent backups and keep track of what you add to your phone so in case there's a problem you know the most recent apps to remove (in my case I couldn't get to my latest backup since DM would shut down with the app conflict).
3) Only consider a device wipe if you have exhausted your apps removal testing. Apps which came on your phone which note the vendor in the About section of the app as RIM should be fine. Also while apps on AppWorld are being offered by BlackBerry there is no certainty that they will work on your phone.

Creative Cloud Desktop Application Manager Unable to Update New Version of PS CC

Windows 7, 64 bit
Received notification of new software for PS CC. Desktop application manager appears, with a creative cloud note over the desktop app mgr saying: " A new ver of CC is available. Update now?" I click update and launching creative cloud desk appears and disappears. Note in bottom right tray says update to cc available and it too disappears.
Looked for help on Adobe website and tried changing name of OOBE to OOBE_old.
Tried to download update directly from PS CC. Went to help; update; It failed to update completely and left the following error message:
Adobe CSXS Infrastructure 4
Installation failed. Error Code: U44M1P7
Now PS CC has lost some of functionality.
Marc

Genius.
Worked a treat, although, as Lion hides the User's Library folder I had to launch Terminal to make it visible first. Do you think the fact the Library's now invisible might've been an issue here?
Whatever, all working now and Creative Cloud Files all synced again.
Thanks very much Jeff.

Populating dynamic components in a remotely connected desktop application

Hii Javaties
I develping a desktop appliaction, which will remotely connect to internet.
My requiremnets for the project are
1)- Combo boxes, lists are dynamic(they need 2 be populated from databse).Since user will not be always connected to internet , so i need to devise some other way 2 do this .
the solution tht i m thinking upon is tht , the comboboxes ,lists will be populated fom XML file tht will be stored in user P.C(rather tht this file will be in jar file of the desktop application).
So now whenever user has access to net, then he can click on a menu
button (UPDATE FILES), so tht he can get the latest copy from the central server .
In the central server , the data will be stored in an RDBMS , and this data will be sent 2 the application on client computer as an XML file.
and this will rewrite the (XML)files , tht the appliaction needs for poplulating Combo boxes and lists.
2)User needs to transmit data back to central server remotely.
I plan to use XML for this.
Now My questions are -------
1) Is this approach Correct ?
2) if the data is large , is it wise to store it as an XML file
3) How 2 go abt it.
If anythng is not clear , plz tell me ?
U can also click on the link below to see the original question posted by me
http://forum.java.sun.com/thread.jspa?threadID=734442

I don't understand why you need xml for jcombobox content? A flat file for each combobox will serve its purpose quite well.the contents of combo boxes will be fetched , from a repository (XML) file, which will contain data from database.
This repository can be aslo updated by connecting to server,and updating it with new data from database.
If u still have dobt do tell me .?

MSS Reporting - Cannot choose Manager's Desktop Application Category

Dear experts,
I need to add reports to Reporting in mss. I am trying to custom Reports in launchpad (fpb_launchpad_cust). I can see the reports in folder. However, I can't add new application under Manager's Desktop Application Category.
Is there any other configuration i need to do?
We are using SAP Netweaver Portal 7.0 and ecc6.
Thanks for any assistance,
Nanie Arianie

Solution:
1. In the SAP HCM System choose:
SAP Easy Access Menu
Transaction SE38
2. In the ABAP Editor: Initial Screen enter the Program FPB_LP_WRITE_ENTRIES and choose Execute.
3. In the Report FPB_LP_WRITE_ENTRIES screen select the MSS Reporting and MSS with Folders options and deselect the checkbox Test Run.
4. Choose Execute. The sample entries are entered in the Report Launchpad in the portal.
5. Log on to the portal with User manager1 and check if the sample entries are displayed.
6. In the ECC system leave the transaction and go back to the SAP Easy Access Menu.
7. Enter transaction PWPC_CONV_MDT_TO_LPA in the Command field.
8. In the Report to convert MDT table entries to LPA table entries screen, enter the MDT Scenario RPT0 and deselect the Test run checkbox.
9. Choose Execute. The list in the next screen shows the reports which have been added to the Report Launchpad.

Error Message trying to connect BB and Desktop Manager

I've had my BB for a few months now, and I used to be able to connect it to my laptop and sync Outlook data. Now it won't connect to the Desktop Manager any more. I always get an error message, and this is the technical data it "Sends" to whomever, in the error reporting:
C:\DOCUME~1\GAYLEE~1\LOCALS~1\Temp\WERc171.dir00\DesktopMgr.exe.mdmp
C:\DOCUME~1\GAYLEE~1\LOCALS~1\Temp\WERc171.dir00\appcompat.txt
How do I get BB to connect to DM and start syncing again?
Thanks for help.
Solved!
Go to Solution.

i am seeing alot of sync issues lately, the forced windows security update last week looks like it might be the culprit. reinstalling DTM has fixed it for a couple PCs for me. just thinking if you are goign to uninstall 4.3, might as well upgrade on the install.

HT204266 App store icon dissappeared from screen on ipad2, also cannot download or manage my apps in itunes when connected to my desktop

App store icon dissappeared from screen on ipad2, also cannot download or manage my apps in itunes when connected to my desktop. Need help!!

For the App Store icon check Settings>General>Restrictions. You may have restricted the installing of apps and the icon will disappear.
If that's not it, swipe from screen to screen as you may have moved the icon.
You can also reset the home screen layout and the icon will reappear - but the home screen will return to the way that it looked when you first activated your iPad.
Settings>General>Reset>Reset Home Screen Layout.
More information is needed about the apps not syncing or downloading. Are you signed into the same ID on the iPad as your are using in iTunes on your computer and are you talking about iTunes on the computer being the problem?

Disable BB Desktop application startup when handset connected

I would like to manually start BB desktop application on Mac10.6.8 and not to start automatically when the hanset is connected via USB

Thks for your quick reply. I cannot open any devices or apps in "my comptr" while playbook is plugged in. The screen greys and Windows stops responding. I can open "devices & printers" right click on BB cd drive then click on find new drivers. Windows says I already have most current drivers installed. I have an older laptop running Win XP. with no problems connecting to PB. My issue seems simular to those addressed in a later post by prochejr. This appears to be a Win 7 prob. Log in "trouble shooting" tells me application (BB desktop software) has incompatability issues with computer OS.

Blackberry 8800 closes the connection with the desktop manager

i have blackberry 8800... when i try to connect with the desktop manager 5.0 it connects flawlessly but after some seconds a message appears that your device has lost the connection with the desktop manager but even then the usb sign stil being showed infront of the battery indicatior... after some seconds of losing the connection, it connects again and disconnects again and this is goes on ....
i need help please
regards

please help me . is theres any solution to it. done battery replacment reset. but nothing happens

How can i connect multiple forms using swings or applets(AWT) & with D-Base

Hello Friends,
I am Sreedhar from Hyderabad. working as a java developer in a small organization. I got a challenge to work on java stand alone (desktop) application. Basically our company is based on SCM(Supply Chain Management), I never work before using swings and AWT. now my present challenge is to develope an application on swings and AWT using Net Beans IDE. but i am unble find the code to connect one form to another form, i want to develop similar application like a web application , suppose if i click on OK button it has to connect next form. in the next for it has to take user name and password should allow me to access main form. please help me about this topic, if anybody interested i can send u the screen shots and i can post to ur mail. please help me as soon as possible,

sreedharkommuru wrote:
Hello Friends,
I am Sreedhar from Hyderabad. working as a java developer in a small organization. I got a challenge to work on java stand alone (desktop) application. Basically our company is based on SCM(Supply Chain Management), I never work before using swings and AWT. now my present challenge is to develope an application on swings and AWT using Net Beans IDE. but i am unble find the code to connect one form to another form, i want to develop similar application like a web application , suppose if i click on OK button it has to connect next form. in the next for it has to take user name and password should allow me to access main form. please help me about this topic, if anybody interested i can send u the screen shots and i can post to ur mail. please help me as soon as possible,There is no magic, you need to spend a good amount of time in tutorials, here is a good one to start off with:
[The Really Big Index|http://java.sun.com/docs/books/tutorial/reallybigindex.html]
Here are a few tips:
1 - Do not mix AWT and SWING: it'll just cause you headaches in the long run that you cannot fix without refactoring to properly not mix the 2 together.
2 - You use JDBC to access the database
3 - You make accessors/constructors to pass parameters that you need from one form to another.
Have fun.

RMI service not working only inside desktop application creatd in netbeans

Actually I have made an RMI service which works just fine inside a normal java application which I have created in netbeans 6.1, now the problem aries when I put this code inside a desktop application creatd in netbeans 6.1, see the code below, when I use this code in desktop application creatd in netbeans 6.1 the application hangs at the line as shown below;
String[] list = registry.list();
well I do not no why it just hangs there and after three or for minutes it returns with some error, I have shown the error in the end. What it seems to me that inside desktop application creatd in netbeans 6.1 the application can not get registry.list() or registry list.
try
registry = LocateRegistry.getRegistry(serverAddress, 1099);
String[] list = registry.list();
if( list == null )
throw new RemoteException( "list == null" );
else
for (int k=0; k < list.length; k++)
System.out.println("registry" + k + ": " + list[k].toString());
System.getProperties().setProperty("java.security.policy", "wideopen.policy");
// Create and install a security manager
if(System.getSecurityManager() == null)
System.setSecurityManager(new RMISecurityManager());
rmiServer = (ReceiveNodeInterface)(registry.lookup("RMIServiceToSendNodesHierarchy"));
String text = "Please, send us the root node.";
rootNode = rmiServer.getRootNode(text);
treeModel = new DefaultTreeModel( rootNode );
jTreeOPCservers.setModel(treeModel);
catch(RemoteException e){
e.printStackTrace();
catch(NotBoundException e){
e.printStackTrace();
the error is ;
java.rmi.ConnectIOException: Exception creating connection to: 192.168.1.142; nested exception is:
java.net.SocketException: Connection reset
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:614)
at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:198)
at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:184)
at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:322)
at sun.rmi.registry.RegistryImpl_Stub.list(Unknown Source)
at tagbrowser.TagBrowser.getRootNodeIntoTree(TagBrowser.java:198)
at tagbrowser.TagBrowser.<init>(TagBrowser.java:83)
at desktopapplication1.DesktopApplication1View.MyAction(DesktopApplication1View.java:217)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

No I am sure that I am not starting the RMI Registry with socket factories at the server. Next I am sure that the RMI Registry is running. Infect as I have said in the start that I have made an RMI service which works just fine inside a normal java application which I have created in netbeans 6.0.1 the problem aries when I put this code inside a desktop application creatd in netbeans 6.0.1 or 6.5 both.

HOW TO WRITE A DESKTOP APPLICATION IN JAVA

Hi guys
I am new to JAVA.Doing my garduation.
I want to write a desktop application in java, not browser based applet based.
I am stuck at some points
1)like how can i make the application run like the same way we run an .exe file
2)about the database connection
"For example, what are the issues in running a
Java application from a local C: drive on an Intel PC
that needs to access a local database or Excel file? "
Please guide me
Thanks
Tinu Joseph

Hi guys
I am new to JAVA.Doing my garduation.
I want to write a desktop application in java, not
browser based applet based.
I am stuck at some pointsLike how to write Java properly at all?
1)like how can i make the application run like the
same way we run an .exe fileWrite a .bat or .cmd file and have it start your Java app. Or Google for tools to create .exe for you.
2)about the database connection
"For example, what are the issues in running a
Java application from a local C: drive on an Intel PC
that needs to access a local database or Excel file?
"Better learn JDBC. Google for "JDBC tutorial".
%

Should EntityManaer be Closed in a Desktop Application Environment

Hi All,
I'm developing a desktop application with persistence api to connection to database. The application consists of two simple classes Order and Customer, where Customer is used as a field in Order. There is a ManyToOne relationship from Order to Customer and a OneToMany relationship from Customer to Order.
I have another class DBManager for managing all the database activities. All the methods in the class will create an entityManager and close the entityManager once they finish their own operation. An example method is as following:
public void addOrder(Order order) throws Exception
        try {
            entityManager = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT).createEntityManager();
            entityManager.getTransaction().begin();
            entityManager.persist(order);
            entityManager.getTransaction().commit();
        } finally {
            if (entityManager.isOpen())
                entityManager.close();
    }As all entity instances will become detached once the entity manager is close. If I execute the above method, I'll receive an error saying that "Cannot persist detached object.", where the object refers to the Customer object stored in the Order.
I found that there are two ways to fix this problem, I can either merge the Customer object back to the context as following:
public void addOrder(Order order) throws Exception
        try {
            entityManager = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT).createEntityManager();
            entityManager.getTransaction().begin();
            order.setCustomer(entityManager.merge(order.getCustomer()));
            entityManager.persist(order);
            entityManager.getTransaction().commit();
        } finally {
            if (entityManager.isOpen())
                entityManager.close();
    }or I can leave the entityManager unclosed after any operation as following:
public void addOrder(Order order) throws Exception
            entityManager = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT).createEntityManager();
            entityManager.getTransaction().begin();
            entityManager.persist(order);
            entityManager.getTransaction().commit();
    }Both ways would work but I'm not sure which one is the best practice to handle the situation. I know that in EJB environment the entityManager should never be closed, but according to article http://java.sun.com/developer/technicalArticles/J2SE/Desktop/persistenceapi/, entityManager should always be closed when it is no longer needed. I'm therefore very confused about which way to go. Can anyone please give me some advice on that?
Thanks in advance. You help would be greatly appreciated.
Edited by: EWL on Feb 18, 2008 4:37 PM

There are a couple of combining usage issues that are providing the problem. The issue is not specifically with you closing the EM but that combined with your usage of the persist() api. This test case would have the same issue in an EJB environment even if you were not closing the EM.
When using the persist() api you are depending on the behaviour that managed objects are ignored by the persist when infact you should be using multiple APIs depending on the state of the Entities that your application is interacting with.
The best approach is to interact with the EM within your application code. This allows you to share the same EM across all of a particular business call or logical application transaction. This could be wrapped within a DBManager but you would need to expose the concept of transactions to the application. This ensures you can track the lifecycle state of the Entities involved while allowing you to easily manage the EM resource.
If your architecture requires the DBManager pattern you have developed then you should only use persist() on Entities that you know to be new and merge() otherwise. In the example you have provided you could simply swap out persist() for merge() in your addOrder method (without the additional customer merge) and the code should work as you expect allowing you to close the EM.
You will need to close() or clear() the EM at some point within your application. Otherwise you are sure to run out of memory.
--Gordon

Managing Connections in a desktop Application or Applet

Similar Messages

Maybe you are looking for