Java 27 and 26: runnable demos and captured output for every JEP, plus version lanes

Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01B38FGKKam5SCGgwgduVAh3
2026-09-21 15:08:50 +00:00
commit f59c1de96d
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+#!/usr/bin/env bash
+# JEP 536: JFR in-process data redaction. Start a JVM that has secrets in its arguments, system
+# properties and environment, record it with JFR, and print what ended up in the recording.
+#   ./scripts/jfr-redaction.sh   -> docs/output/40-jfr-redaction.txt
+set -euo pipefail
+source "$(dirname "$0")/env.sh"
+B="$ROOT/build/jfr"; rm -rf "$B"; mkdir -p "$B"
+"$JDK27/bin/javac" --release 26 -d "$B" "$ROOT/jep-tour/src/Idle.java"
+
+# record <label> <jdk> <FlightRecorderOptions value or empty>
+record() {
+  local label="$1" jdk="$2" opts="${3:-}" jfr="$B/$1.jfr"
+  local fropt=(); [ -n "$opts" ] && fropt=("-XX:FlightRecorderOptions:$opts")
+  DB_PASSWORD=hunter2 "$jdk/bin/java" -Dapi.token=abc123 -Dregion=ap-south-1 "${fropt[@]}" \
+      -XX:StartFlightRecording:filename="$jfr" -cp "$B" Idle --password=hunter2 --user=ankur >/dev/null 2>&1
+  echo "=== $label"
+  [ -n "$opts" ] && echo "    -XX:FlightRecorderOptions:$opts"
+  "$jdk/bin/jfr" print --events jdk.JVMInformation "$jfr"          | grep -E 'jvmArguments|javaArguments' | sed 's/^ *//' | sed -E 's/(-XX:StartFlightRecording:filename=)[^ "]*/\1<file>/'
+  "$jdk/bin/jfr" print --events jdk.InitialSystemProperty "$jfr"   | grep -A1 -E 'key = "(api.token|region)"' | grep -v -- '^--$' | sed 's/^ *//' | paste - -
+  "$jdk/bin/jfr" print --events jdk.InitialEnvironmentVariable "$jfr" | grep -A1 -E 'key = "DB_PASSWORD"'      | grep -v -- '^--$' | sed 's/^ *//' | paste - -
+  echo
+}
+
+{
+  echo "# The process under test: java -Dapi.token=abc123 -Dregion=ap-south-1 ... Idle --password=hunter2 --user=ankur"
+  echo "# with DB_PASSWORD=hunter2 in the environment. Which of those values reach the recording?"
+  echo
+  record "jdk26-default"                     "$JDK26"
+  record "jdk27-default"                     "$JDK27"
+  record "jdk27-own-list-replaces-defaults"  "$JDK27" "redact-argument=--user*,redact-key=region"
+  record "jdk27-plus-extends-defaults"       "$JDK27" "redact-argument=+--user*,redact-key=+region"
+  record "jdk27-none-disables-redaction"     "$JDK27" "redact-argument=none,redact-key=none"
+} > "$OUT/40-jfr-redaction.txt" 2>&1
+cat "$OUT/40-jfr-redaction.txt"