This week's book giveaway is in the Design forum.
We're giving away four copies of Building Microservices and have Sam Newman on-line!
See this thread for details.
The moose likes JDBC and Relational Databases and the fly likes Connection Objects & Scope Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login


Win a copy of Building Microservices this week in the Design forum!
JavaRanch » Java Forums » Databases » JDBC and Relational Databases
Bookmark "Connection Objects & Scope" Watch "Connection Objects & Scope" New topic
Author

Connection Objects & Scope

Elam Daly
Greenhorn

Joined: Aug 09, 2003
Posts: 16
Hi all,

I'm doing the Sun JDBC tutorial and am confused on something.
If I declare a Connection object outside of a try/catch block, shouldn't the connection be valid outside of the try/catch block in which it is actually initialized?

I'm getting a 'variable con might not have been initialized' error. Does this mean that I have to enclose everything in a giant try/catch block?
The code works if I put the 'con=DriverManger.getConnection( url )' inside of the 2nd try block, but that can't be efficient. Opening a connection everytime to do a query?


Thanks.

[ June 18, 2004: Message edited by: elam daly ]
[ June 18, 2004: Message edited by: elam daly ]
Blake Minghelli
Ranch Hand

Joined: Sep 13, 2002
Posts: 331
'variable con might not have been initialized'

The variable con is accessible outside of the try/catch but the compiler is smart enough to recognize that it is possible that con might never be assigned a value, not even null. Local variables are not automatically null like instance variables.
The easiest thing to address that is to change

to

The difference is subtle but this ensures that con is definitely assigned some value before it is used again, and therefore makes the compiler happy.


Blake Minghelli<br />SCWCD<br /> <br />"I'd put a quote here but I'm a non-conformist"
 
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com
 
subject: Connection Objects & Scope
 
It's not a secret anymore!