Start script for Paper based on the one of PocketMine-MP and which uses the JVM flags listed here

start.sh

#!/usr/bin/env bash
FLAGS="-Xms256M -Xmx3584M -XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:+AlwaysPreTouch -XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40 -XX:G1HeapRegionSize=8M -XX:G1ReservePercent=20 -XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 -XX:InitiatingHeapOccupancyPercent=15 -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1RSetUpdatingPauseTimePercent=5 -XX:SurvivorRatio=32 -XX:+PerfDisableSharedMem -XX:MaxTenuringThreshold=1 -Dusing.aikars.flags=https://mcflags.emc.gs -Daikars.new.flags=true $FLAGS"

DIR="$(cd -P "$( dirname "${BASH_SOURCE[0]}" )" && pwd)"
cd "$DIR"

while getopts "l" OPTION 2> /dev/null; do
	case ${OPTION} in
		l)
			DO_LOOP="yes"
			;;
		\?)
			break
			;;
	esac
done

LOOPS=0

set +e

if [ "$DO_LOOP" == "yes" ]; then
	while true; do
		if [ ${LOOPS} -gt 0 ]; then
			echo "Restarted $LOOPS times"
		fi
		java $FLAGS -jar paper-*.jar nogui
		echo "To escape the loop, press CTRL+C now. Otherwise, wait 5 seconds for the server to restart."
		echo ""
		sleep 5
		((LOOPS++))
	done
else
	exec java $FLAGS -jar paper-*.jar nogui
fi