Unlocking Java's Code Maze
summary
Interactive quiz with 20 exercises runs live on a phone app and shows runnable code snippets and IntelliJ demos plus concrete answers and surprises: static initialization prints 20, string concatenation yields "result is 16", flatMap flattens nested lists, generics cause a ClassCastException on get, records equal by content but != by reference, List.of throws UnsupportedOperationException, ConcurrentHashMap merge yields 2000, AtomicInteger ends at 2, sealed types cause a compilation error, CompletableFutures benefit from allOf, use new virtual thread per task executor and the RandomGeneratorFactory for performance.
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chapters (20)
- 0:00Java code exploration
- 1:16Interactive exercises format
- 5:10Static variable warm-up
- 7:42Stream partitioning vowels
- 9:33Optimizing list grouping
- 12:21Generics and type erasure
- 15:20String concatenation precedence
- 18:09Nested collection streams
- 19:52ConcurrentHashMap merge
- 23:06Atomic counters
- 24:54Sealed classes interfaces
- 28:29Records equals comparison
- 31:00Immutable list challenge
- 33:04Stream skip limit
- 35:14CompletableFuture allOf
- 39:12Lambda predicate optimization
- 41:41Map putIfAbsent
- 44:38Virtual threads concurrency
- 47:14Random number optimization
- 49:23Q&A
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