Code Test In... Java?

So I get an opportunity to do a code test for a company that peaked my interest, but the catch is since I'm self-taught I have to do it in Java. They threw out a few reasons for this, one being it will show how well I pick up a language I have no experience with... I don't know how someone else may have felt about it, but I thought it would be interesting to try even if they decide not to bring me on.

I did somewhat of a crash course to get the basics down-- I used Codecademy and some YouTube and got a good start on the application. I did have some hiccups with what methods/ syntax I could use, but I used what I knew about JavaScript to guide me some when doing searches.

I have a few pages of notes as I went, but here's some things off the top of me head...

A few things:

1. declaring variables by type, ie: int age;.

1(a) speaking of declaring variables-- final is like const where the variable will not be reassigned, ie: final int PIE = 3.14.

1(b) Casting- converting from one data type to another, ideally from smaller to larger:

double cDbl = 1.234;
int cInt = (int)cDbl;

2. System.out.println() is like console.log().
3. It's all about the " " instead of ' ', and don't forget to end with ;.
4. When you set up your class and constructor, code to be executed goes in the following: public static void main(String[] args) {}. With that said, there must be atleast one class in a Java application and one main method (per application, not class).
5. When you look to return from a method you declare the data type as with a variable (as stated above), if the method will not be returning anything you use void.
6. When method returning an Integer, using an if/else statement and if condition calls for it, return 0;-- it must return something since it was declared.
7. When using a simple file MyClass.java, script title will match class MyClass {}.
8. To compile: javac MyClass.java; To run: java MyClass.

I wanted to incorporate testing as well. The testing setup was a bit time consuming, the popular thing seems to be to set everything up using Eclipse or something similar, but I really wanted to try and keep things simple using my normal editor and the terminal. Thankfully I found a few things where I was able to piece it together. The gist:

1. Make a test file, ie: MyClassTest.java, I kept it in the same folder as my MyClass.java file.
2. jUnit - Console Launcher
3. Snagged executable junit-platform-console-standalone-1.4.0.jar, threw it in my folder where my files were.
4. To compile: javac -cp .:junit-platform-console-standalone-1.4.0.jar MyClassTest.java.
5. To run tests: java -jar junit-platform-console-standalone-1.4.0.jar --class-path . -c MyClassTest

This post doesn't document everything I came across or my final output, but I wanted to (at the very least) document the gist of this little side quest I found myself on...

note: to future self, you never touched Java, yet got something set up; correct output and with passing tests-- by no means a Java expert, but you got something going and working, good for you :D