launch_jar_app.sh

#!/bin/bash

# Startup script for java jar applications
##########################################
###        SET GC PARAMETERS         #####
##########################################

#Specify the minimum java version
MIN_JAVA_VERSION = 17

#Specify the initial heap size of the application
JAVA_HOME=${JAVA_HOME:-/usr/jdk/latest/}

#Specify the initial heap size of the application
HEAPSIZE=2048

#Specify the heap for young objects
YOUNGSIZE=256

#Specify the platform type ( 32 or 64 bit)
PLATFORM=64

# Default size of memory allocated to store the classes metadata (metaspace for JDK 8 and above, permgen for older JDK version)
CLASSESMETADATASIZE=256

# Special native memory space (not GC managed) used to store compiled code from the JIT
CODECACHESIZE=128

# Jar file
JAR_FILE=myapp.jar

# Properties File
PROPFILE=myapp.properties

# Process Name
SERVICE_NAME=MYAPP

# Main class name
MAIN_CLASS=com.myapp.Main

# Find where this script is located
WHEREAMI=`dirname $0`

# Find dirs we need
HOME=${_HOME:-$WHEREAMI/..}

# Put all third party jars in /home/lib
LIB=${_LIB:-$HOME/lib}


#
# Makes sure that the file passed in argument are available in the $BIN directory.
# Exits on failure.
#
checkFile()
{
    for i in $1;
      do
      if [ ! -f $HOME/$i ];
          then
          printf "*** Error: Unable to find configuration file \$HOME/%s\n*** Exiting\n" $i
          exit 1;
      fi
    done
}

#
# Init the main jar file and goes through all files within $LIB directory and appends into JARFILE var
#
initJarLibs()
{
	JARFILES=$LIB/$JAR_FILE
    for jar in $LIB/*.jar;
      do
      if [ ! -z "$VERBOSE" ];
          then
          printf "\t\$LIB/%s\n" `basename $jar`
      fi
      if [ $jar != $LIB/$JAR_FILE ];
        then
          if [ -z "$JARFILES" ] ;
              then
              JARFILES=$jar
        else
              JARFILES=$JARFILES:$jar
        fi
        fi
    done
}

# Run the Service
# --------------------------------------
if [ ! -z "$VERBOSE" ];
        then
        printf "\n=== Running Application ===\n\n"
fi

# Look for jar file
checkFile JAR_FILE

# Look for properties file
checkFile PROPFILE

# Init all jar files available
initJarLibs

######### START DATE TIME #####
year=`date '+%y'`
month=`date '+%m'`
day=`date '+%d'`
hour=`date '+%H'`
minute=`date '+%M'`
time=$hour$minute
date=$year$month$day

###############################

##### GET JAVA VERSION ########
JAVA_VERSION=$(java -version 2>&1 | sed 's/java version "\(.*\)\.\(.*\)\..*"/\1\2/; 1q')

echo =============================================
echo ===          Running SERVICE              ===
echo =============================================

##################################################
#################  JVM OPTIONS  ##################
##################################################
JVM_OPTIONS="-XX:CompileThreshold=1000 -XX:-UseCounterDecay"

# Specific parameters depending on java version
if [ $MIN_JAVA_VERSION -gt $JAVA_VERSION ] 
then
    printf "*** Error: MINIMUM REQUIRED JAVA VERSION: $MIN_JAVA_VERSION ****"
    exit 1;
elif [ $JAVA_VERSION -ge 18 ] # JAVA VERSION 1.8.0 or newer
then
        CLASSESMETADATASIZE_OPTION="-XX:MetaspaceSize"
        CLASSESMETADATAMAXSIZE_OPTION="-XX:MaxMetaspaceSize"
        HTTPSERVER_READTIMEOUT_OPTION="-Dsun.net.httpserver.maxReqTime"
        USEPARNEWGC_OPTION=""
        TIERED_COMPILATION_SWITCH="-XX:-TieredCompilation"
elif [ $JAVA_VERSION -ge 17 ] # JAVA VERSION 1.7.0 or newer
then
        CLASSESMETADATASIZE_OPTION="-XX:PermSize"
        CLASSESMETADATAMAXSIZE_OPTION="-XX:MaxPermSize"
        HTTPSERVER_READTIMEOUT_OPTION="-Dsun.net.httpserver.maxReqTime"
        USEPARNEWGC_OPTION="-XX:+UseParNewGC"
        TIERED_COMPILATION_SWITCH=""
fi

PLATFORMOPTION=""
DATAMODEL=""
if [ $PLATFORM -eq 64 ];
then
   PLATFORMOPTION=-XX:+UseCompressedOops
   DATAMODEL=-d64
fi

$JAVA_HOME/bin/java ${DATAMODEL} \
  -D${SERVICE_NAME} \
  ${PLATFORMOPTION} \
  -server \
  -Xms${HEAPSIZE}M \
  -Xmx${HEAPSIZE}M \
  ${CLASSESMETADATASIZE_OPTION}=${CLASSESMETADATASIZE}m \
  ${CLASSESMETADATAMAXSIZE_OPTION}=${CLASSESMETADATASIZE}m \
  -XX:NewSize=${YOUNGSIZE}m \
  -XX:MaxNewSize=${YOUNGSIZE}m \
  -XX:InitialCodeCacheSize=${CODECACHESIZE}m \
  -XX:ReservedCodeCacheSize=${CODECACHESIZE}m \
  -XX:-UseBiasedLocking\
    ${TIERED_COMPILATION_SWITCH} \
    $JVM_OPTIONS \
    ${MAIN_CLASS} &
set +x