Window->Preferences->Java->Code Style->Code Templates:
Comments->Types: Javadoc style of class, use Alt+Shift+J create;
Code->New Java Files: Code Template of New Created Java Class File;
Check "Automatically add comments for new methods and types" if you want javadoc added to your new created java file automatically.
Here is my javadoc template of types:
/**
-
${type_name}
-
@author Chad
-
Created: ${date}
-
Last Modified: ${date}
-
${tags}
*/