Write multi-line string in Spring boot .conf file - syntax

Question

For my Spring boot application, I have a .conf file that is used to run the application.
In this file, I put some jvm options.
Currently it contains this :
JAVA_OPTS="-Xms256m -Xmx512m -Dvisualvm.display.name=ApplicationWs -Dcom.sun.management.jmxremote.port=3333 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false"
In the future I will certainly add other options and the line will increase in size.
I want to make it more readable by writing one or two options by line. But I don't find the proper syntax for this.
I want to do something like this :
# Heap Size
JAVA_OPTS="-Xms256m -Xmx512m"
# JVisualVM Name in VisualVM
JAVA_OPTS="$JAVA_OPTS -Dvisualvm.display.name=ApplicationWs"
# Jmx Configuration
JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.port=3333 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false"
I already tried :
JAVA_OPTS="-Xms256m -Xmx512m"
JAVA_OPTS="$JAVA_OPTS -Dvisualvm.display.name=ApplicationWs"
export JAVA_OPTS
JAVA_OPTS="-Xms256m -Xmx512m"
JAVA_OPTS="${JAVA_OPTS} -Dvisualvm.display.name=ApplicationWs"
export JAVA_OPTS
JAVA_OPTS="-Xms256m -Xmx512m
-Dvisualvm.display.name=ApplicationWs"
JAVA_OPTS="-Xms256m -Xmx512m "
+ " -Dvisualvm.display.name=ApplicationWs"
What is the proper syntax for a multi-line string in a spring-boot .conf file ?

Answer 1

Spring boot launch script will use the shell to source the .conf file, so you can put any shell script syntax to write the configuration. I would prefer to use vars to format them in your case such as the following:
MEM_OPTS='-Xms256m -Xmx512m'
DISPLAY_NAME='visualvm.display.name=ApplicationWs'
JMXREMOTE_PORT='com.sun.management.jmxremote.port=3333'
JMXREMOTE_SSL='com.sun.management.jmxremote.ssl=false'
JMXREMOTE_AUTH='com.sun.management.jmxremote.authenticate=false'
JAVA_OPTS="${MEM_OPTS} -D${DISPLAY_NAME} -D${JMXREMOTE_PORT} -D${JMXREMOTE_SSL} -D${JMXREMOTE_AUTH}"
see here

Answer 2

Try multiple line like this:
primes = 2,\
3,\
5,\
7,\
11
from: https://stackoverflow.com/a/8978515/404145

Answer 3

Only way that actually works is to pass one line command, note semicolons and backslashes in the end:
MEMORY_PARAMS=' -Xms512M -Xmx512M '; \
JMX_MONITORING='-Dcom.sun.management.jmxremote.port=8890 -Dcom.sun.management.jmxremote.rmi.port=8890 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote -Djava.rmi.server.hostname=13.55.666.7777'; \
REMOTE_DEBUG='-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:8889'; \
JAVA_OPTS=" -Dfile.encoding=UTF-8 ${MEMORY_PARAMS} ${REMOTE_DEBUG} ${JMX_MONITORING} "