1. CS230 Tutorial Week 4

2. Agenda
More Java (Very Briefly!)
Useful Eclipse Tips!
More questions.

3. final Lang-ref Section 4.12.4, 8.1.1.2, 8.3.1.2, 8.4.3.3
Generally means ‘constant’
A final variable/field can be assigned only once.
A final class cannot be subclassed.
A final method cannot be overridden.
COMPILE-time error if violated.
Very useful in nested classes and lambda-expressions.

4. Generics No such thing in Python --- duck typing.
No such thing in C --- weakly typed.
Very powerful feature (but optional) in C template metaprogramming.
Mandatory to program functionally --- Haskell and ML.
Java generics sits between C and C easier to use/less powerful than C++, but still very useful.
Added after Java 5.0 (in 2004!) --- has to be backwards compatible --- type erasure and JVM.

5. Generics Lang-ref Section 4.4 --- 4.10 (Especially 4.5)
Basic syntax is very easy!
List<String> list = new ArrayList<String>();
list.add("hello, world!");
Detailed semantics is very tricky! --- Probably not useful to know to program Java at this level.

6. Nested Classes
Rather unpleasant feature of Java --- very wired semantics.
Lang-ref Section 8.1.3
static vs non-static nested classes.
Most time you want a nested class, it’s a static nested class.

7. Eclipse Features
More than just syntax --- Eclipse understands semantics.
Eclipse understands your code (and Java), and can give you suggestions.
Eclipse also has a very useful set of refactoring tools that can perform many of the standard refactoring techniques (in book Refactoring: Improving the Design of Existing Code by Martin Fowler) automatically.

8. Demos Auto-generate boilerplate code/comment.
Correct Indentation/Format
Auto-complete.
Code suggestions.
Rename/Move.
Show references.
More advanced refactoring techniques --- extract methods/interfaces/super classes, pull up/down, etc.