Free online Java IDE for AP CS A on Chromebooks

CS Room is a free online Java IDE for AP Computer Science A (AP CSA) that comes with the whole classroom. Every student gets their own Java workspace in the browser, and you hand out labs, autograde them with your own tests, and keep every score in a gradebook. It runs on school Chromebooks without turning on Linux, and it's free, from the nonprofit Birdflop.

Why AP CS A needs a real environment

The 2025–26 course adds reading text files with File and Scanner, and keyboard input needs a real terminal. Desktop IDEs such as BlueJ need Linux on a Chromebook, which many schools turn off, and e-book code panels such as CSAwesome2's can't take user input.

A Java IDE that runs on Chromebooks

• Java 25: click Run and CS Room compiles and runs the program in a terminal, other classes in the folder included.
• Scanner reads typed input, and new Scanner(new File("data.txt")) reads a real file.
• Files save as students type and are there all year, on any computer.
• Labs graded by input/output cases or JUnit tests, with hidden tests deciding the grade.
• Due dates that collect and grade work, a gradebook with weights and CSV export, and live editing in any student's workspace.

Set up your AP CS A class

1. Request a teacher account. We set teachers up within a day or two.
2. Create a class and share its class link.
3. Add a lab with New assignment, uploading starter code or starting from scratch.
4. Add tests: pick Java for input/output cases, or Java (Maven) for JUnit. See Writing assignment tests.
5. Publish with a due date.

CSAwesome2, the free College Board–endorsed curriculum, pairs well: students read and practice in the e-book, then write full labs in CS Room.

Before you switch

CS Room brings the environment, the classroom and the grading, not an AP curriculum, and students sign in to use it.

Request a free teacher account to set up your first Java lab.