-- Enabling the extension
{-# OPTIONS -fglasgow-exts #-} 

--  Equal like class
class  MEEq a  where
   (=-=)   :: a -> a -> Bool

-- Instances with no implementation
instance MEEq ()
instance MEEq Bool
instance MEEq Int

-- The rewrite rule
{-# RULES
    "eq/Bool"   (=-=) = eq_Bool :: Bool -> Bool -> Bool
    "eq/Unit"   (=-=) = eq_Unit :: ()   -> ()   -> Bool
    #-}

main = do
       print $ True =-= False
       print $ ()   =-= ()
       -- This fails (at runtime!) since we didn't define a rule for it
       print $ 7    =-= (8 :: Int)

-- Makes sure to fail any instance that doesn't have an implementation on compile time
{-# RULES
    "Unable to resolve instance resolution" (=-=) = (=-=)
      #-}

Haskell uses static dispatch for overloaded methods, in addition it has an extension to write rules that optimize Haskell dispatching code.

Haskell static dispatch rewrite rules

Java