CSC 207.01 2019S, Class 03: Getting started with Java development
- Notes and news
- Upcoming work
- Extra credit
- Eclipse lab
- Git lab
News / Etc.
- We’ll follow the new partner methodology.
- Partner names on the board.
- See email about “Do not partner me with” option.
- Please turn in your academic honesty policy if you have not done so
- If you’re not on the csstudents list, you probably should be. Let me
know if you’d like to be added.
- Mentor sessions at 7:00 p.m. Sunday nights.
- You will have a substitute teacher on Wednesday. I’ll be off learning
about Fairness, Accountability, and Transparency in Artificial Intelligence.
- If you feel unsafe coming to class on Wednesday, send me an email message
and I will treat it as an excused absence. You are, however, responsible
for making up the work on your own.
- When you send me questions about assignments, please title them
things like “QUESTION on Assignment 2”. It makes it much easiere
for me to identify them as questions.
- In case it wasn’t clear from the syllabus and such, I will randomly
call on students in class. I do this for multiple reasons.
- It avoids bias (conscious and unconscious). Since I’m using cards,
I am unlikely to ask more questions of people from certain groups.
- It builds skills. For better or for worse, many people expect you
to express your ideas, even when you have not formulated them
completely. Practice in a low-stakes environment should help.
- It can remind you that you are not alone in confusion or
misunderstanding. While I may sometimes force you to guess, you
can feel free to answer “I’m not sure” when I call on you.
- It sometimes incentivizes you to ask questions. If you know
that I might ask you questions, you may be more inclined to ask
- And more.
- If being called on in class causes severe anxiety, let me know and
we’ll figure out a way to adjust to support you.
- I’ve updated the due time for lab writeups; writeups are generally due
at the start of class.
- You should be able to access everything on the current eboard by
.html at the end of the URL.
- Assignment 1 due Thursday night.
- Reading due before class Wednesday.
- No lab writeup for Monday’s class.
- Kindness through gratitude, Monday and Tuesday 11-1, outside DHall.
Other good things
Tell me about the organization of a Java program
Java programs consist of multiple classes that work together.
Each class (normally) resides in its own file. More precisely,
each public class has to be in its own file; you can add private
classes to a file with a public class.
By default, Java programs need a public, static,
main, that takes
an array of strings as parameters.
We use the
main method that appears in the command when you
start the Java program.
java HelloWorld means “run the main
method in the
That main method (and other methods) can … (a) run “normal” code;
(b) call static methods in the same class; (c) call static methods
in other classes with
ClassName.method; (d) create objects
new ClassName(params); (e) call methods on those created
For levels of groups, Java also supports packages (a group of classes)
and modules (a group of packages). We will not use modules, which
were just introduced.
Can you have a method that’s not static?
Yes. Just don’t write the word
static. That method will then
require that you create an object and it can use the fields and
methods of that object. (See Wednesday’s class.)
How should we format code?
See the Google Java Style Guide.
Our goal is consistency, which helps readers (and writers) (and graders).
Fun and a chance for all of us to learn a bit. (More or less.)
- Computers are sentient and malicious!
What should commit comments look like?
A note that will remind you what you just did.
“Add the HelloWorld class.”
“Prepare the project for use in Eclipse.”
“Squash the bug."
“Refactor the code in HelloWorld.”
Things Eclipse gives you …
- On-the-fly syntax checking. (You’ll see a red x at the left.)
- Contextual documentation.
- Some automation (e.g., for refactoring, moving files).
- Enough that it overwhelms some folks.
- Lots of warnings on the command line.
Things Git gives you …
- An easy way to share code.
- A history of your project.
- Ways to see changes.