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From "Bryan Pendleton (JIRA)" <derby-...@db.apache.org>
Subject [jira] Created: (DERBY-668) SysInfo can give misleading information when JDBC jars are loaded from jre/lib/ext
Date Tue, 01 Nov 2005 22:16:55 GMT
SysInfo can give misleading information when JDBC jars are loaded from jre/lib/ext
----------------------------------------------------------------------------------

         Key: DERBY-668
         URL: http://issues.apache.org/jira/browse/DERBY-668
     Project: Derby
        Type: Bug
  Components: Build tools  
    Versions: 10.1.1.0    
    Reporter: Bryan Pendleton
    Priority: Minor


There is a section in the SysInfo tool's output titled "Derby Information", which prints location
and version information for the major Derby jars. Here is an example of that output:

--------- Derby Information --------
JRE - JDBC: J2SE 1.4.2 - JDBC 3.0
[/home/bpendleton/src/derby-subversion/trunk/jars/insane/derby.jar] 10.2.0.0 alpha - (315052M)
[/home/bpendleton/src/derby-subversion/trunk/jars/insane/derbytools.jar] 10.2.0.0 alpha -
(315052M)
[/home/bpendleton/src/derby-subversion/trunk/jars/insane/derbynet.jar] 10.2.0.0 alpha - (315052M)
[/home/bpendleton/src/derby-subversion/trunk/jars/insane/derbyclient.jar] 10.2.0.0 alpha -
(315052M)
[/home/bpendleton/downloads/derby/db2jcc/lib/db2jcc.jar] 2.4 - (17)
[/home/bpendleton/downloads/derby/db2jcc/lib/db2jcc_license_c.jar] 2.4 - (17)

Unfortunately, this tool can be fooled if you arrange for one of these jar files to be loaded
from a magic location like $JAVA_HOME/jre/lib/ext.

For example, I had (accidentally) placed an old version of db2jcc.jar into $JAVA_HOME/jre/lib/ext.
When I ran SysInfo, it printed out: 

--------- Derby Information --------
JRE - JDBC: J2SE 1.4.2 - JDBC 3.0
[/home/bpendleton/src/derby-subversion/trunk/jars/insane/derby.jar] 10.2.0.0 alpha - (315052M)
[/home/bpendleton/src/derby-subversion/trunk/jars/insane/derbytools.jar] 10.2.0.0 alpha -
(315052M)
[/home/bpendleton/src/derby-subversion/trunk/jars/insane/derbynet.jar] 10.2.0.0 alpha - (315052M)
[/home/bpendleton/src/derby-subversion/trunk/jars/insane/derbyclient.jar] 10.2.0.0 alpha -
(315052M)
[/home/bpendleton/downloads/derby/db2jcc/lib/db2jcc.jar] 1.0 - (581)
[/home/bpendleton/downloads/derby/db2jcc/lib/db2jcc_license_c.jar] 1.0 - (581)

However, the "1.0 (581)" information actually came from $JAVA_HOME/jre/lib/ext/db2jcc.jar,
NOT from
/home/bpendleton/downloads/derby/db2jcc/lib/db2jcc.jar.

It would be nice if SysInfo could detect the difference between a jar file being loaded via
the application class loader using $CLASSPATH, and a jar file being loaded via the system
class loader using JDK library extensions.

To reproduce the problem, simply:
1) Place an older version of db2jcc.jar into $JAVA_HOME/jre/lib/ext
2) Place a newer version of db2jcc.jar into your $CLASSPATH
3) Run SysInfo. You will see that it prints the name of the jarfile from $CLASSPATH, but the
version info from the JDK copy.


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