Convert many examples to java backend

**do not review yet**
But I think it worked before, didn't it?  @andreistefanescu ?  Again, I'm OK with letting it pass in the interest of moving on with our plan, but in that case:
1) Add a code comment the first time it appears that we will fix it using strictness to look more syntactic
2) Add a github issue about it, to make sure we do not forget it