Preparing for the Java 21 Certification (or Learning New Features)
summary
Covers the exact Java 18–21 features that appear on the certification and walks through practical gotchas: text blocks rules (triple-quote placement, incidental vs essential whitespace, backslash escapes), records with compact constructors and immutability pitfalls, sealed classes and pattern matching for instanceof/switch (scope and exhaustiveness rules), sequence collections behavior, and lightweight virtual threads with new executor factory and Thread.ofVirtual. Notes actionable changes: UTF‑8 default, String.repeat, split limit, and finalization marked for removal, with interactive exam-style questions throughout.
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chapters (13)
- 0:00Introduction
- 0:32Java 21 certification
- 2:06Text blocks and string apis
- 7:13Sequenced collections
- 9:43Text block review questions
- 14:56Records and sealed classes
- 18:44Records review questions
- 21:47Instanceof pattern matching
- 26:17Switch expressions and patterns
- 30:02Record patterns and questions
- 34:44Virtual threads
- 39:24Thread review questions
- 40:05Final features and Q&A
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