How do I list the files installed by a deb package?

Yes, use the dpkg command like

dpkg -L hadoop-0.20

The converse question (finding the package providing a given file) is answered with e.g.

dpkg -S /usr/include/gc/gc.h

Read more about Debian packaging related tools.

P.S. Ubuntu (and other Linux distributions, e.g Mint) is a derivative of Debian.

What files are installed on your system varies from package to package. To be 100% sure you should take a look into the .deb package yourself. Download the package first.

First you need to extract the .deb archive:

ar vx mypackage.deb

Now this should result in three new files: debian-binary, control.tar.gz and data.tar.gz. You're interested in the last one.

Now you can extract it as well using tar:

tar xzvf data.tar.gz

Now you can browse the package content freely. Look for any makefiles, install scripts and such like to see where things gets installed.

You can list the installed files for a package by passing the --listfile flag to dpkg. For example, if your package is actually named "hadoop-0.20" then:

dpkg --listfiles hadoop-0.20