Spring Boot 4 and the Spring portfolio now provide null-safe APIs using JSpecify annotations to help prevent NullPointerExceptions. The Spring team has annotated most major projects including Spring Framework 7, Spring Data 4, and Spring Security 7 with explicit nullability information. Developers can leverage this through IDE support (IntelliJ IDEA 2025.3+) for warnings, or use build-time checkers like NullAway for stricter enforcement. Kotlin 2 automatically translates these annotations to native Kotlin nullability. This allows teams to choose their level of null-safety adoption, from simple IDE warnings to fully null-safe applications, without breaking existing APIs.

Paul Hudson built Hacktivate, a capture-the-flag game teaching cybersecurity fundamentals to teens through 240 challenges covering SQL injection, cryptography, networking, and steganography. The app runs entirely locally on Apple devices using Swift and SwiftUI, featuring a sandboxed environment with simulated servers, terminals, and networks. Inspired by classic games like Syndicate and Command & Conquer, it combines retro aesthetics with practical skills like packet sniffing, hash cracking, and digital forensics. The 45,000+ lines of code include a Linux terminal emulator, web server, and various security tools, all designed to provide structured, privacy-preserving learning without external dependencies.

Vibe coding with AI agents is effective for shipping side projects quickly, but removes the satisfaction and learning that comes from hands-on development. While tools like GitHub Copilot and Spec Kit can automate implementation from specifications, watching agents write code is tedious and lacks the joy of problem-solving. The author reserves AI-assisted coding for projects where only the final output matters, preferring to manually build applications where the tech stack or implementation details are interesting.