CodeBlanks: Learn Java Coding

CodeBlanks teaches Java by doing, not reading.

Each problem shows you a working solution with key lines blanked out. You pick the right token from a pool and snap it into place — building real code from the inside out, not copy-pasting from a hint.

Stuck? The built-in AI tutor gives Socratic hints at 4 levels:

• Nudge — points you in the right direction

• Hint — explains the concept

• Pseudocode — shows the logic without the syntax

• Guided code — walks you through the solution

87 problems from easy to hard, organised by the Google 30-day interview list: arrays, strings, hash maps, trees, graphs, dynamic programming, and more — great for coding interview prep and DSA practice.

NEW: Refresh — a swipeable feed of quick Java & Spring Boot concept flashcards. Swipe through core concepts, framework internals, and comparisons (like @Component vs @Bean), ask the built-in AI chat a follow-up question on any card, search for a specific topic, and pick a session length that fits your time. Concepts you flag as tricky resurface sooner next time.

No account needed. No data stored. Just open and practise.

Earn extra AI hints by watching a short rewarded ad.