Free online Java IDE for AP CS A on Chromebooks

CS Room is a free online Java IDE for AP CSA (AP Computer Science A) that works on school Chromebooks with Linux turned off. Students write and run Java in the browser. You post labs, your tests grade them, and the scores land in a gradebook.

What AP CS A needs from an IDE

The 2025–26 course adds reading text files with File and Scanner. Keyboard input needs a terminal to type into. Desktop IDEs such as BlueJ need Linux on a Chromebook, and many schools turn Linux off. The code panels in e-books such as CSAwesome2 can't take user input.

A Java IDE that runs on Chromebooks

Students click Run and CS Room compiles the program, along with the other classes in its folder, and runs it in a terminal on Java 25. Scanner reads what they type, and new Scanner(new File("data.txt")) reads a file in their workspace. Files save as they type and are there all year, on whichever computer they sign in from.

For grading:

• Input/output cases or JUnit tests, with hidden tests deciding the grade.
• Due dates that collect and grade the work.
• A gradebook with weights and CSV export.
• Live editing in any student's workspace when someone is stuck.

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 doesn't come with an AP curriculum, and students need to sign in.

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