SIMILARITIES BETWEEN JAVA AND .NET :
->  Both are Object oriented programming languages.
->Both use their own intermediate language. Java calls it as byte code and .NET  calls it as MSIL code.
->  Both are platform independent.
-> Both support ―Garbage collection‖, which automatically clears the unused memory.
->  Both offer better security features in their own style.
->  Both support Remoting.
->  Both support multi-threading.
->Both of these support to develop console applications, windows applications, websites, web services etc.
->  Both support web related languages like Java Script, XML, CSS etc.
->  Both support the recent web development technology like AJAX.
->Both support to develop the applications for small devices like PDA‘s, mobile phones, smart phones etc.