Give me an implementation of Java that actually runs fast enough to get out of its own way, and I will be happy to reconsider it.

Until then, give me only a tool that has stood the test of time:   not the chisel that stood beside a block of stone and sought to “subclass” it into a sculpture of an elephant, but the trusty tool that pounded away at it for hours on end, removing every single thing from the block that did not look like an elephant, and that emerged from this arduous task just as sharp as ever before. Give me only the tool that has been lovingly cleaned and oiled and stored carefully back into its box, not because the tool needs coddling but because it has served its master well.

Nevertheless, realize also that if your boss or the company or the department has made an executive decision to pursue a different course, you will accomplish little or nothing by setting yourself against that tide. Flow with it, learn what you can, and be very restrained in your criticism. There is, after all, “more than one way to do it.” Many factors contribute to such a weighty business decision, and you might not be privy to them all. Whether you deem the decision to be right or wrong, it is not yours (alone) to make. “It's their boat,” and the Captain's word upon the deck of his own boat is final. If you have expressed your sentiment clearly but once, as surely you have ... Mark my words!! ... say no more of it! Not even to your co-workers, not even in private.