Java Assessment Exercise
The purpose of this exercise is to assess your Java programming skills coming
into this class. Please submit by Wednesday 11:59 PM so that I may give you
feedback before the add/drop deadline. I may recommend that some of you drop
the course if your programming skills are not up to par. Submission of this
exercise will take the place of attendance today. The actual score will only
be used to measure your pre-existing skills and will not count towards the
final grade.
Another purpose of this exercise is to familiarize you with the workflow for
this course. We are going to use GitHub for collaboration and source code
versioning, and also for submitting to GradeScope. Once your code is submitted
to GradeSCope, the autograder will automatically test your code and assign a
score depending upon the pass/fail of each test case. The autograder will also
give you valuable feedback on the deductions you got so that you can fix your
mistakes and resubmit to get a higher score. There is no limit to the number
of submissions.
Please follow the below instructions.
## Install JDK 8
The official Java version for this class is Java 8 (1.8.0.231). Please install the Java package for your OS at:
https://drive.google.com/drive/folders/1E76H7y2nMsrdiBwJi0nwlzczAgTKKhv7
After installation, make sure you have the correct Java and Javac versions by doing “java
-version” and “javac -version”. You should get something like the following:
“`
$ java -version
java version “1.8.0_231”
Java(TM) SE Runtime Environment (build 1.8.0_231-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.231-b11, mixed mode)
“`
Alternatively, you can use these versions of OpenJDK 8 that have been verified to work with our tool chain:
* https://chocolatey.org/packages/openjdk8
* https://chocolatey.org/packages/zulu8
After installing, they should show their respective versions on “java -version”. For example, for zulu8:
“`
$ java -version
openjdk version “1.8.0_265”
OpenJDK Runtime Environment (Zulu 8.48.0.53-CA-win64) (build 1.8.0_265-b11)
OpenJDK 64-Bit Server VM (Zulu 8.48.0.53-CA-win64) (build 25.265-b11, mixed mode)
“`
If you don’t see the correct version (either for JDK 8, OpenJDK 8, or Zulu 8), please follow the below instructions to
set up the Path OS environment variable.
### Setting up JDK 8 for Windows
1. Search “environment” in the Windows 10 search box.
2. Open “Edit the system environment variables” control panel.
3. Click on the “Environment Variables” box.
4. Search the “Path” environment variable in user variables and system variables.
5. Add the bin directory of the Java installation, probably “C:\Program Files\Java\jdk1.8.0_231\bin” to the top of the “Path”
6. For good measure, you may want to remove other Java installations from the “Path”
7. After this, try doing “java -version” again and it should have changed.
If you use [Chocolatey](https://chocolatey.org/) as your package manager, and you opted to install OpenJDK 8, you will have to replace the above Java bin path with the path where Chocolatey installs the package.
### Setting up JDK 8 for MacOS
1. Open ~/.bash_profile with your favorite editor (if you don’t have one, just do “pico ~/.bash_profile”)
2. Add the following 2 lines at the bottom
“`
export PATH=/Library/Java/JavaVirtualMachines/jdk1.8.0_231.jdk/Contents/Home/bin:$PATH
export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_231.jdk/Contents/Home/
“`
3. Save the file and exit from the terminal
4. Relaunch the terminal and try doing “which java”. It should say /Library/Java/JavaVirtualMachines/jdk1.8.0_231.jdk/Contents/Home/bin/java.
5. Now you are good to go! Otherwise, try doing “echo $PATH” and see if your path is not updated properly, or if there is some other Java installation before you.
Alternatively, you can use [jEnv](https://www.jenv.be/) that allows you to switch Java versions easily on a Mac. You will also need [Mac brew](https://brew.sh/) if you don’t already have it. These are just one liners to install so it should be pretty painless.
It’s a brew installation so it should be pretty painless.
## Create GitHub Repository
For every source code submission in this class, you are asked to create a new
GitHub repository. If you don’t already have a GitHub account, please create
one. If you are new to GitHub, there is a short git tutorial under the
lectures folder: [Using_Git.pdf](/lectures/Using_Git.pdf). Please refer to it
as you follow the below instructions.
1. If you are new to git source versioning or GitHub, I recommend that you
start by using the Desktop GUI version. You can download it from:
2. Once you’ve installed GitHub Desktop, let’s first clone the course repository to your computer:
https://help.github.com/en/desktop/contributing-to-projects/cloning-a-repository-from-github-to-github-desktop
You will need to go to the root of the course repository to get the clone link:
https://github.com/wonsunahn/CS1632_Spring2021
This way, you will have always have up=to-date course materials on your
computer. Whenever there are updates to the course materials, the “Pull”
request button will be activated for the repository on GitHub Desktop. Clicking
that button will bring your local folder in sync with the updated materials.
3. Next, create a new repository just for this exercise:
https://help.github.com/en/desktop/getting-started-with-github-desktop/creating-your-first-repository-using-github-desktop
You can name it whatever you want (but preferably something easy to remember, right?).
Once you’ve created the repository, copy over the contents of just the exercise
folder in the course repository to the new repository folder. Once you’ve
copied over the files, you need to “Commit” and “Push” the files to upload
those files to GitHub. If you are successful, you should be able to see your
new repository with the new files at github.com.
4. Whenever you make improvements to your source code, frequently “Commit” and
“Push” those changes to GitHub so that your new changes are versioned.
## Compilation
Go to the new repository folder you created for this exercise and make sure that the Java file compiles:
“`
$ mkdir bin
$ javac -d bin src/*.java
“`
You should see no errors at this point
## Running
Try running the compiled class file:
“`
$ java -cp bin SortedCollection
Usage: java SortedCollection [num1] [num2] [num3] …
“`
The SortedCollection main method just prints usage information when no
commandline arguments are passed. With commandline arguments, it should print
out the commandline arguments in sorted order, from smallest to largest:
“`
$ java -cp bin SortedCollection 3 2 1
sorted: 1 2 3
“`
But at the current state, SortedCollection is incomplete and prints out:
“`
$ java -cp bin SortedCollection 3 2 1
sorted: 0 0 0
“`
Your job is to complete SortedCollection so that it works properly.
## Completing SortedCollection.java
The places in source code where you are asked to insert or modify code are
marked by // TODO comments. Feel free to use any data structure from java.util
or one of your own. It doesn’t matter how you implement it as long as it works
as specified. Pay attention to the Javadoc comments on top of each method.
## Submission
You will do GitHub submission to GradeScope.
1. By now you should have created a new github repository just for this
exercise. Make sure you keep the repository *PRIVATE* so that nobody else
can access your repository. Once you are done modifying code, don’t forget to
commit and push your changes to the github repository.
2. When you are done, submit your github repository to GradeScope at the “Java
Assessment Exercise” link. Once you submit, GradeScope will run the
autograder to grade you and give feedback. If you get deductions, fix your
code based on the feedback and resubmit. Repeat until you don’t get
deductions.
IMPORTANT: Please keep the github private! This applies to all future submissions.
## GradeScope Feedback
GradeScope feedback is your friend. Submit as many times as you want to get
frequent feedback. There are 10 tests for this exercise and if there is an
error, the error message will tell you what was expected what was observed.
When the compared value is a string, brackets ([, ]) are used to annotate
exactly which part of the two strings differed.
The tests were done using an automated testing infrastructure called JUnit that
allows you to rigorously test software. You will eventually learn to use this
tool too as part of this course!
## Resources
* JDK 8 installation packages:
https://drive.google.com/drive/folders/1E76H7y2nMsrdiBwJi0nwlzczAgTKKhv7
* Java 8 API reference manual:
https://docs.oracle.com/javase/8/docs/api/overview-summary.html
