On the Terminal, type:
echo "$JAVA_HOME"
If you are not getting anything, then your environment variable JAVA_HOME has not been set. You can try using "locate java" to try and discover where your installation of Java is located.
If $JAVA_HOME
is defined in your environment...
$ echo $JAVA_HOME
$ # I am not lucky...
You can guess it from the classes that are loaded.
$ java -showversion -verbose 2>&1 | head -1
[Opened /usr/lib/jvm/java-1.7.0-openjdk-1.7.0.75.x86_64/jre/lib/rt.jar]
This method ensures you find the correct jdk
/jre
used in case there are multiple installations.
Or using strace
:
$ strace -e open java -showversion 2>&1 | grep -m1 /jre/
open("/usr/lib/jvm/java-1.7.0-openjdk-1.7.0.75.x86_64/jre/bin/../lib/amd64/jli/tls/x86_64/libpthread.so.0", O_RDONLY) = -1 ENOENT (No such file or directory)
Did you set your JAVA_HOME
http://www.gnu.org/software/sed/manual/html_node/Print-bash-environment.html#Print-bash-environment
If you really want to get some info about your BASH put that script in your .bashrc and watch it fly by. You can scroll around and look it over.
I know this is late, but this command searches the /usr/ directory to find java for you
sudo find /usr/ -name *jdk
Results to
/usr/lib/jvm/java-6-openjdk
/usr/lib/jvm/java-1.6.0-openjdk
FYI, if you are on a Mac, currently JAVA_HOME is located at
/System/Library/Frameworks/JavaVM.framework/Home
To show the value of an environment variable you use:
echo $VARIABLE
so in your case will be:
echo $JAVA_HOME
In case you don't have it setted, you can add in your .bashrc
file:
export JAVA_HOME=$(readlink -f /usr/bin/java | sed "s:bin/java::")
and it will dynamically change when you update your packages.
Just another solution, this one's cross platform (uses java
), and points you to the location of the jre.
java -XshowSettings:properties -version 2>&1 > /dev/null | grep 'java.home'
Outputs all of java
's current settings, and finds the one called java.home
.
For windows, you can go with findstr instead of grep.
java -XshowSettings:properties -version 2>&1 | findstr "java.home"
On Linux you can run $(dirname $(dirname $(readlink -f $(which javac))))
On Mac you can run $(dirname $(readlink $(which javac)))/java_home
I'm not sure about windows but I imagine where javac
would get you pretty close
Here's an improvement, grabbing just the directory to stdout:
java -XshowSettings:properties -version 2>&1 \
| sed '/^[[:space:]]*java\.home/!d;s/^[[:space:]]*java\.home[[:space:]]*=[[:space:]]*//'
Source: Stackoverflow.com