MySQL Bugs: #87099: DBMD.getProductVersion() throws NPE when Connection is closed

Bug #87099	DBMD.getProductVersion() throws NPE when Connection is closed
Submitted:	17 Jul 2017 17:28	Modified:	6 Sep 2021 9:29
Reporter:	Mark Matthews	Email Updates:
Status:	Can't repeat	Impact on me:	None
Category:	Connector / J	Severity:	S3 (Non-critical)
Version:	5.1.38	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
Calling DatabaseMetaData.getDatabaseProductVersion() for a connection that has been closed results in a NullPointerException being thrown. Public API methods for JDBC aren't supposed to throw NullPointerExceptions, instead a SQLException with the appropriate SQLState should be thrown. The stack looks like:

java.lang.NullPointerException
	at com.mysql.jdbc.ConnectionImpl.getServerVersion(ConnectionImpl.java:3035)
	at com.mysql.jdbc.DatabaseMetaData.getDatabaseProductVersion(DatabaseMetaData.java:2829)

The offending code is in ConnectionImpl:

public String getServerVersion() {
        return this.io.getServerVersion();
}

(this.io is null once the connection has been closed).

How to repeat:
Call .getDatabaseProductVersion() on a DBMD instance that has been previously returned from Connection.getMetaData(), and then the connection is closed.

Suggested fix:
Any methods in DBMD that reference the connection should first check that the underlying connection hasn't been closed. (HEAD still has this bug - https://github.com/mysql/mysql-connector-j/blob/release/5.1/src/com/mysql/jdbc/ConnectionI...)

Posted by developer:
 
Hi Mark,

Thank you for reporting this.

Posted by developer:
 
This bug is not reproducible with the latest Connector/J 8.0.

Connector/J 5.1 series came to EOL on Feb 9th, 2021, see https://www.mysql.com/support/eol-notice.html, so this bug will not be fixed there.