SJK (Swiss Java Knife) launcher script

sjk.sh

#!/usr/bin/env bash
set -Eeuo pipefail
if [[ -z "${JAVA_HOME:-}" ]]; then
  JAVA='java'
else
  JAVA="$JAVA_HOME/bin/java"
fi

SJK_VERSION='0.20'
SJK_PATH="$HOME/.local/opt/sjk/sjk-plus-$SJK_VERSION.jar"
SJK_URL="https://repo.maven.apache.org/maven2/org/gridkit/jvmtool/sjk-plus/$SJK_VERSION/sjk-plus-$SJK_VERSION.jar"
SJK_SHA256='c10aeb794137aebc1f38de0a627aaed270fc545026de216d36b8befb6c31d860'

# Download sjk-plus.jar if not downloaded yet.
if [[ ! -a "$SJK_PATH" ]]; then
  echo "Downloading SJK .."
  cleanup() {
    rm -f "$SJK_PATH.tmp"
  }
  trap cleanup ERR
  trap cleanup EXIT
  trap cleanup SIGINT

  mkdir -p "$(dirname "$SJK_PATH")"
  cleanup
  curl -L -o "$SJK_PATH.tmp" "$SJK_URL"
  if [[ ! "$(sha256sum "$SJK_PATH.tmp")" =~ (^$SJK_SHA256) ]]; then
    echo 'Downloaded JAR has incorrect SHA256 checksum'
    exit 1
  fi
  mv "$SJK_PATH.tmp" "$SJK_PATH"
  echo
fi

if [[ "$#" -eq 0 ]]; then
  ARGS=('--commands')
else
  ARGS=("$@")
fi

exec "$JAVA" --add-opens java.base/jdk.internal.perf=ALL-UNNAMED --add-opens jdk.attach/sun.tools.attach=ALL-UNNAMED -jar "$SJK_PATH" "${ARGS[@]}"

This script is a convenient launcher script for SJK (Swiss Java Knife). It downloads and launches the sjk-plus.jar from Maven Central into ~/.local/opt/sjk.