You might quite experience the tools.jar not found when trying to compile using Maven. This is because when you do the compilation, maven is trying to look for a tools.jar which is not available for the compilation and hence you get this exception.
Fatal error compiling: tools.jar not found: C:\Program Files\Java\jre6\..\lib\tools.jar -> [Help 1]
Make sure, you have the JDK in the installed JRE and selected for your compilation needs.
Goto Windows -> Preferences
Java -> Installed JREs – > Execution Environment
JavaSE1.x -> JDE 1.x
If you don’t have the JDK in the Installed JRE, then
Select the Installed JRE and Add the JDK installed path