Problem in running tar xvzf command

Hello all.
I have actually downloaded the hadoop 2.7 tar.gz file from its website using the apt-get install command. Now when I am trying to untar it using the tar xvzf command, it is actually throwing me error saying that it is not in the gzip format while it really is in gzip format. Attached is the screenshot.
Just trying to find a solution for this.
Thanks in advance.