AsyncHandlerExample.java

//fetch something from A to make a lookup on B
ADao adao = new ADao();
adao.findByIdAsync(123,h1->{
  if(h1.succeeded()){
    BDao bdao = new BDao();
    bdao.findBySomeAValueAsync(h1.result().getSomeAValue(),h2->{
      if(h2.succeeded()){
        //do something with the result
      }else{
        //oops something went wrong
      }
    });
  }else{
    //oops something went wrong
  }
});