2/27/2007

Don't copy jar files in auto-loaded directories

Jar files in some directories are automatically loaded into JVM in some applications. Some examples of these magic directories are, common/lib and shared/lib in Tomcat, $JAVA_HOME/jre/lib/endorsed, $JAVA_HOME/jre/lib/ext, etc. This can ease the task of classpath management, to some extent. But we should also be very careful while doing anything in these directories. Specifically, do not put any unused *.jar files in these directories, since they will also be loaded by java runtime and may cause conflict.

Sometimes I need to try a different version of a jar. I rename the old jar to foo-02272007.jar and copy the new jar over. In an auto-loaded directory, this may cause nasty random errors due to conflict between 2 versions of the same jar. I should really back up the old jar as foo.jar.20202007 without a .jar extension to exclude it from auto-loading.

3 comments:

Shivani said...

wonderful blog :)

eMexo Technologies said...

Good Post! Thank you so much for sharing this pretty post, it was so good to read and useful to improve my knowledge as updated one, keep blogging.

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eMexo Technologies said...

Good Post! Thank you so much for sharing this pretty post, it was so good to read and useful to improve my knowledge as updated one, keep blogging.

Internet Of Things training in electronic city