Use 'tar' command to uncompress .xz compressed files
tar xvfJ filename.tar.xz
But remember, .xz formats are supported only from tar 1.22 version.
If you have a lower version of tar like me, then either you can update your tar command or download xz utilities. To update the tar command, type as shown below:
yum update tar
Note: In case, if "yum update" didn't work for you, then you may download "tar" source and compile it.
Use 'XZ' utils to un-compress .xz files
$wget http://tukaani.org/xz/xz-5.0.5.tar.gz $cd xz-5.0.5 $./configure $make $sudo make install
Once the package is installed, run the below command to uncompress .xz file formats.
xz -d filename.tar.xz
