[Proxool-developer] concurrency bug in Prototyper class?

[Matt S. <msa...@gm...>]

It seems Class Prototyper should either acquire the lock on private member
'lock' whenever it reads or modifies 'connectionCount' or make
'connectionCount' a volatile variable.

Prototyper.buildConnection( ) acquires the lock to read and modify
'connectionCount' but other methods do not: Prototyper.sweep( ),
Prototyper.connectionRemoved( ) and Prototyper.getConnectionCount().

I started poking around after my application started seeing
ProxoolExceptions indicating the maximum connection count had been reached
and discovered what appears to be a memory visibility issue.  If calls to
Prototyper.connectionRemoved( ) and Prototyper.buildConnection( ) happen in
different threads there could be unwarranted ProxoolExceptions for reaching
the maximum connection count - a 'connectionPool' decrement might not be
visible to the threads calling Prototyper.buildConnection( ).