Android : Mobile OS, languages for their APPs and HTML 5

There are the 3 popular mobile OS:

1. Android


2. iOS


3. 
   

   Windows Phone

   
   
   
   
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     Which programming language (s) is used for their apps, for each of the 3?

     
     
   
   
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     Is HTML 5 a replacement for any of the languages? if not, what's the hype with HTML 5 and mobile apps?

     
     
   
   
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     Java is cross platform (I believe because of JVM), can java be used to write apps for all the 3?