CS++ Java IDE

CS++ Java IDE is a focused, offline Java environment for students learning to code — and a complete AP Computer Science A practice platform.

Write code in a real Java IDE designed for touch. Run programs instantly with the bundled Java runtime — no internet, no compiler setup, no accounts. Tap Run and your code executes on your device.

WHAT'S INCLUDED
• Multi-file Java editor with syntax highlighting, line numbers, auto-indent, and a templates menu
• Bundled Java runtime — runs your code locally, even in airplane mode
• A debugger: tap a line number to set a breakpoint, then step through your program and watch its variables
• Unit 1 free: 13 starter problems covering primitive types, output, and your first algorithm
• Full AP CSA course (one-time $9.99 unlock): 11 units, 50+ inline coding challenges, persistent progress

REAL JAVA, WELL PAST THE AP SUBSET
Everything AP CSA uses, and much more of the language: the java.util collections (ArrayList, LinkedList, HashMap, TreeMap, HashSet, TreeSet, ArrayDeque, Stack, PriorityQueue), your own generic classes, inner and anonymous classes, interfaces with default methods, lambdas, method references, streams, Optional, and exceptions, including your own. It is tested against the real JDK, so your programs print what Java prints, and compile errors read like javac's.

DESIGNED FOR LEARNING
• Each challenge tests your output against expected results
• Inline error messages with the exact line and what went wrong
• "Format" button cleans up indentation in one tap
• Templates menu loads 14 starter projects: Scanner input, reading a text file, ArrayList, 2D arrays, inheritance, and the four AP FRQ types
• Progress saved on-device — pick up where you left off

UNIVERSAL
Built for iPhone and iPad. The editor and console scale from 4-inch phones to 13-inch iPads, with a full-bleed editor on phones to maximize coding space.

OFFLINE-FIRST
No account creation. No login. No data sent off your device. Lessons, code, and progress all live in the app's local storage. Use it on a flight, in a classroom with no Wi-Fi, or anywhere.

THE FULL AP CSA COURSE
Unit 1 is free. Unlock all 11 units for $9.99 (one-time, no subscription):
1. Primitive Types & Output
2. Using Objects
3. Boolean Expressions & if
4. Iteration
5. Writing Classes
6. Array
7. ArrayList
8. 2D Array
9. Inheritance
10. Recursion
11. Sorting & Searching

Built by Yellow Dart Publishing for csplusplus.com — the College Board–aligned CS curriculum used by teachers across the U.S.