Thread-safety in javax.jdbc.DataSource?

Question

Hi.
I am using Tomcat with an Oracle DB, and using the Oracle DataSource and thin client implementation for my connection pooling. I am wondering if the javax.sql.DataSource class is threadsafe. That is, if I have a DataSource defined for my application in Tomcat's server.xml, and have code...
javax.sql.DataSource ds = null;
javax.naming.Context ctx = null;
java.sql.Connection conn = null;
ctx = new InitialContext();
ds = (DataSource)ctx.lookup("myDataSource");
conn = ds.getConnection();
... if two threads execute this code at the same time, will there be any threading problems? Will ds.getConnection() blowup? Or will two clients get different instances of DataSource that are not inter-dependant? Is this application server specific?
Could someone post a URL to someplace that discusses threading issues in these cases? Thanks.

Answer 1

... if two threads execute this code at the sametime,
will there be any threading problems? Will
ds.getConnection() blowup? Or will two clients
get
different instances of DataSource that are not
inter-dependant? Is this application server
specific?this actually will never happen, because each is
happening in its own context.Huh?
The code runs is a single VM. That means two threads
can access it at the same time.
two threads access it at the same time? what does it stand for? each time you want to have a connection obj from datasource, you would have to get an object that represents the physical databsource first and use this obj to get connections. where is the thread safty issue?
to make sense, maybe the question needs to be rephrased to read: can the physical datasource handle concurrent requests
It has nothing to do with context.when you are getting an object that represents the physical datasource, you would need to do it via jndi after initializing the context, required by the jndi deal.
>
however, i did post a question to all the dbasaround
me like this: if two orcal db users executed anupdate
or insert or delete sql stmt, what will happen? the
answer i got was it will never happen.Again what?
Of course two users can execute two expressions at the
same time. That is an expectation of high
perforamance servers. And it quickly becomes relevent
on multi-cpu boxes.
this is very much like if the physical datasource can handle concurrent requests. can they, oracle and the datasource, handle concurrent requests truthfully? for example, if mary is selecting a value frome a field of table which john happen is about to change. if mary and john execute their sqls exactly at the same time, what will mary see in that field? the new value or the old one?