I believe that the teacher was telling him to start with Java because it's one of the more rigorous languages (in respect to introductory languages). I myself initially started with learning Java in high school and after leaning it, other languages such as C++ (which is the mainstream language in college) became a walk in the park.
Java throws you straight into critical, complex ideals such as classes and objects (since it is very OOP oriented), resulting in over preparing you for related topics such as inheritance and other friend functions.
There are also a lot of other differences, but the two aren't as foreign as you're portraying.
What I meant is that they shared no common technical base, something people tend to think because of the name similarity. Based on your description, C++ and possibly Perl would also be similar (in a way they are yes, but still).
Caius - I guess it depends upon what you are trying to achieve. If it's just writing web sites that's one thing, but if it's computer programming then you must understand that HTML and CSS are not computer programming languages; basically they are what are called mark-up languages and have the sole purpose of specifying how text and other data are displayed on a screen. A computer program is a very different thing which may involve no output whatsoever (although most programs do display some sort of data).
If it is computer programming that you are interested in, rather than producing web sites, then your teacher is correct (although I might take issue with his particular choice of language). You need to investigate something like Java (good because it exist on many platforms) or if it is just Windows programming then C# is a very good choice (slightly easier to learn - IMO - and a very fine modern programming language). And the great thing is that both of these languages can also be used to produce dynamic web pages.