Hints and tips on java
These are some helpful hints on various topics.
apache
bash
cmd
database
java
javascript
linux
mod_rewrite
mssql
mysql
oracle
os
perl
php
regex
rsync
ssh
unix
web_design
windows
Locating where class is loaded from
When debugging Java application which contains of multiple multiple jars there are a number of cases where one gets lost in all the jars. Then is vital to know where a third party class is loaded from to know its exact version. To get the load location of StrangeClass, just evaluate the following expression in your runtime:
URL location = StrangeClass.class.getProtectionDomain().getCodeSource().getLocation();
Find the jar that contains given Java class
If you have a folder containing several jars and you want to quickly find which one contains given class, use the following script:
findjar.sh:
$dir=$1
$class=$2
if [ $# -ne 2 ]
then
echo "Usage: `basename $0` <directory> <class>"
exit 1
fi
for file in `find $dir -name *.jar`
do
unzip -t $file | grep $class && echo $file
done
Example: find the jar containing MyClass in the folder /my/jars/folder:
findjar.sh /my/jars/folder MyClass
