Useful to fast-check startup time of a spring-boot app with CDS and Jar Extract.

boot-startup-test-millis.sh

#!/bin/bash
mkfifo pipe

APP_NAME="xxx"
GRADLE_OR_MAVEN="gradle"
JAR_NAME="xxx-0.0.1-SNAPSHOT.jar"

# Set to 0 for standard startup
# Only for Java 21+ and Spring Boot 3.3
# - Set to 1 to use fast startup with the new JAR format
# - Set to 2 to use CDS + Jar Format
# - Set to 3 to use CDS + Jar Format + Tiered Compilation
FAST_STARTUP=3

# Create the Jar
if [ "$GRADLE_OR_MAVEN" = "gradle" ]; then
  ./gradlew clean bootJar
else
  mvn clean install
fi

# Decompress the JAR for 1, 2 and 3
if [ "$FAST_STARTUP" -ge 1 ]; then
  java -Djarmode=tools -jar "build/libs/$JAR_NAME" extract --destination fast-jar --force
fi

# Training run for 2 and 3
if [ "$FAST_STARTUP" -ge 2 ]; then
  java -XX:ArchiveClassesAtExit=application.jsa -Dspring.context.exit=onRefresh -jar fast-jar/$JAR_NAME
fi

# Run the application
if [ "$FAST_STARTUP" = 0 ]; then
  java -jar "./build/libs/$JAR_NAME" > pipe & PID=$!
elif [ "$FAST_STARTUP" = 1 ]; then
  java -jar fast-jar/$JAR_NAME > pipe & PID=$!
elif [ "$FAST_STARTUP" = 2 ]; then
  java -Xshare:on -XX:SharedArchiveFile=application.jsa -jar "fast-jar/$JAR_NAME" > pipe & PID=$!
elif [ "$FAST_STARTUP" = 3 ]; then
  java -Xshare:on -XX:TieredStopAtLevel=1 -XX:SharedArchiveFile=application.jsa -jar "fast-jar/$JAR_NAME" > pipe & PID=$!
else
  echo "Invalid FAST_STARTUP value"
  exit 1
fi


# Wait for the application to start
while IFS= read -r line
do
  echo "$line"
  if [[ "$line" == *"Started $APP_NAME"* ]]; then
    echo "----------------- Application started -----------------"
    break
  fi
done < pipe

# Kill the application
kill $PID
rm pipe