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Re: JDBC client causes TNS-12502 on server's listener

From: Enkidu Utnapishtim <>
Date: Fri, 19 Jul 2002 22:16:27 GMT
Message-ID: <>

Rauf Sarwar wrote:

> Enkidu Utnapishtim <> wrote in message news:<>...

>>Thanks for the quick reply Cindy. I checked with the developers and they
>>assure me that they're using Oracle's thin driver.
>>We have just two main Java aps: our WebLogic app that checks connections
>>every 5 mintues (in case database loses a connection) and a "check" app
>>that attempts to connect every 10 minutes (verifies URL is accessible).
>>I can see entries for both of these in the log. But between are all the
>>TNS-12502 errors.
>>C. Ferguson wrote:
>>> what driver are you using to connect to the oracle db? Try using
>>>Oracle's thin driver (type4). See if that makes a difference.
>>>Enkidu Utnapishtim wrote:
>>>>I am trying to research why a JDBC client (WebLogic java app) keeps
>>>>generating a "TNS-12502: TNS:listener received no CONNECT_DATA from
>>>>client" in my server's listener.log file. The message appears every
>>>>minute or so (making my listener.log grow way too fast).
>>>>I checked MetaLink and did a Google search (web and newsgroups).
>>>>Practically every response says to check the tnsnames.ora on the
>>>>client for a valid CONNECT_DATA entry. Well now, that's mighty fine
>>>>advice if the client is anything other than a JDBC (or ODBC)
>>>>connection. As far as I can determine, JDBC completely and totally
>>>>ignores tnsnames.ora anyhow. That's why you have to put connect
>>>>strings like "host:port:sid" in many of Oracle's Java wizards (eg,
>>>>Portal Config Assistant) instead of the alias name from tnsnames.ora
>>>>... so it can construct a JDBC compliant connect string.
>>>>So, my question is, where do I look (if not in the client's
>>>>tnsnames.ora) for the problem?
>>>>Roger Crowley - LearningFramework - DBA
> JDBC thin driver does not require Oracle client installation and
> middleware. It is a pure java driver which sits on top of the TCP
> stack. That is why you need fully qualified TCP ONLY connect string
> as, jdbc:oracle:thin:@<HOST>:<PORT>:<SID>.
> JDBC oci driver, on the other hand, needs Oracle client and middleware
> installation because it uses native API's to connect and uses
> tnsnames.ora to verify connect string as,
> jdbc:oracle:oci7|8:@<Service name from tnsnames.ora file>
> //Rauf Sarwar

Thanks for the clarification. I'm a real novice when it comes to the new java functionality in Oracle (13 years of PL/SQL is hard to give up ... even though it makes communicating with our java developers a bit difficult). I added your descriptons to a running "knowledgebase" of my own (fancy word for a text file where I keep a record of things as I learn them).
Roger Received on Fri Jul 19 2002 - 17:16:27 CDT

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