Ada: http://www.adahome.com/
http://www.rational.com/
http://www.aonix.com/
http://www.rrsoftware.com/
http://www.ghs.com/
GNAT: (Ada Core Technologies): http://www.gnat.com/
For comparison of Java and C go to: http://www.adahome.com/Resources/Languages/chart3.html