Can anybody list some more major software companies and corporate houses "majorly" using the Java platform? Some that instantly came into my mind are Oracle, IBM, twitter.......
Banks and Financial institutions. Every bank and financial institution that I have worked for in in last 10 years has a projects exclusively in either Java or C# or Cobol( yes Cobol is very much alive and kicking on IBM mainframe ) and some C/C++ . On the other hand, these places do not use Ruby or Python.
the banks using C# are most probably windows users, right? (Mono is not for enterprise.....)
I attended a confrence by a company named Micro Focus, and believe me, they were talking about renewing COBOL and teaching it to the undergraduates, making the mainframe relevant to the next generation.
Walmart and JB Hunt still use Java, C#, and Cobol and won't stop any time soon..
Salesforce.com.
Twitter uses Scala.
British Telecom do extensivly
meetup.com uses Java. And Google if you count Android.
Google Web Toolkit and hundreds of various projects made in Google available on code.google.com.