My service implementation uses hibernate dao objects which should be managing 
its own connections via the c3p0 connection pool.  All my service objects and 
Dao objects are marked as singletons in my Spring applicationContext.xml file.  
I don't think any of my transactions are failing as it would most likely throw 
an exception if the there was a problem performing a transactions and all 
exceptions are logged (at least I believe they are).

I will most likely put the following c3p0 settings in place and wait to see 
what comes out of this in production.  


This should give me a stack trace of what checked out a connection, where that 
connection hasn't been returned to the pool in 30 seconds.  It will be a slight 
performance hit on production but I should be able to find the problem very 



-----Original Message-----
From: Dan Retzlaff [] 
Sent: Wednesday, March 21, 2012 5:04 PM
Subject: Re: LDM - correct construction


That won't prevent a connection from being released. The LDM holds a reference 
to the page, and the page has a serializable proxy to the service 
implementation. No problem there. Injecting the service into the LDM is only an 
advantage if you want to share it among pages; then the LDM can be static and 
its page reference goes away.

It sounds like your service implementation may have an issue. Does your service 
manage its own connections? If so, is it a singleton? Other than that, I'd 
guess there's a bug in your transaction management such that a transaction gets 
started but not finished.


On Wed, Mar 21, 2012 at 1:45 PM, Jeffrey Schneller <> wrote:

> Is this the correct construction of a LDM where I need to use a 
> service bean to access my database?  The IMyService bean  is injected 
> on the page and passed to the LDM.  Does this make the LDM hold a 
> reference to the IMyService bean and possibly keep a connection from 
> being put back into the
> c3p0 db connection pool?  After some period of time my application is 
> blocked with all threads waiting on a connection to the db.
> Should I be injected the IMyService bean into the LDM using the 
> commented out code.  Thanks for any help.
> public class MyLDM extends 
> LoadableDetachableModel<com.example.MyObject> {
>                //@SpringBean
>                private IMyService service;
>                private String id;
>                public MyLDM(String id, IMyService service)       {
>                       = id;
>                                this.service = service;
>                }
>                //public MyLDM(String id)           {
>                //   = id;
>                //}
>                @Override
>                protected com.example.MyObject load() { 
> //InjectorHolder.getInjector().inject(this);
>                                return service.getMyObject(;
>                }
> }

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