Rctd-031-javhd-today-0429202202-12-17 Min May 2026

Set<String> adultUsernames = users.stream()
    .filter(u -> u.getAge() >= 18)
    .map(User::getUsername)
    .collect(Collectors.toSet());

The video spends a full 45 seconds walking through this line, annotating each stage with why it’s chosen and what the underlying bytecode looks like (via a brief JIT inspection).

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This document records the design, execution, and outcomes of the “TODAY” performance test run on 04/29/2022. It serves as: RCTD-031-JAVHD-TODAY-0429202202-12-17 Min