diff --git a/src/main/assemblies/files/fess b/src/main/assemblies/files/fess
index e55a37491..e42133a38 100644
--- a/src/main/assemblies/files/fess
+++ b/src/main/assemblies/files/fess
@@ -106,10 +106,10 @@ launch_service()
 
     if [ "x$daemonized" = "x" ]; then
         fess_parms="$fess_parms -Dfess.foreground=yes"
-        exec "$JAVA" $JAVA_OPTS $FESS_JAVA_OPTS $fess_parms -Dfess.es.dir="$ES_HOME" -cp "$FESS_CLASSPATH" $props \
+        exec "$JAVA" $FESS_JAVA_OPTS $fess_parms -Dfess.es.dir="$ES_HOME" -cp "$FESS_CLASSPATH" $props \
                 org.codelibs.fess.FessBoot $FESS_OPTS > /dev/null
     else
-        exec "$JAVA" $JAVA_OPTS $FESS_JAVA_OPTS $fess_parms -Dfess.es.dir="$ES_HOME" -cp "$FESS_CLASSPATH" $props \
+        exec "$JAVA" $FESS_JAVA_OPTS $fess_parms -Dfess.es.dir="$ES_HOME" -cp "$FESS_CLASSPATH" $props \
                 org.codelibs.fess.FessBoot $FESS_OPTS <&- > /dev/null &
         if [ x"$pidfile" != "x" ] ; then
             echo $! > $pidfile
@@ -162,7 +162,7 @@ eval set -- "$args"
 while true; do
     case $1 in
         -v)
-            "$JAVA" $JAVA_OPTS $FESS_JAVA_OPTS $fess_parms -cp "$FESS_CLASSPATH" $props \
+            "$JAVA" $FESS_JAVA_OPTS $fess_parms -cp "$FESS_CLASSPATH" $props \
                     org.codelibs.fess.Version
             exit 0
         ;;
diff --git a/src/main/assemblies/files/fess.bat b/src/main/assemblies/files/fess.bat
index 17ce135a4..edb84ac4c 100644
--- a/src/main/assemblies/files/fess.bat
+++ b/src/main/assemblies/files/fess.bat
@@ -43,6 +43,6 @@ IF ERRORLEVEL 1 (
 	EXIT /B %ERRORLEVEL%
 )
 
-"%JAVA_HOME%\bin\java" %JAVA_OPTS% %FESS_JAVA_OPTS% !newparams! -cp "%FESS_CLASSPATH%" "org.codelibs.fess.FessBoot"
+"%JAVA_HOME%\bin\java" %FESS_JAVA_OPTS% !newparams! -cp "%FESS_CLASSPATH%" "org.codelibs.fess.FessBoot"
 
 ENDLOCAL
diff --git a/src/main/assemblies/files/fess.in.bat b/src/main/assemblies/files/fess.in.bat
index 59a398909..f1e292e63 100644
--- a/src/main/assemblies/files/fess.in.bat
+++ b/src/main/assemblies/files/fess.in.bat
@@ -30,70 +30,70 @@ REM min and max heap sizes should be set to the same value to avoid
 REM stop-the-world GC pauses during resize, and so that we can lock the
 REM heap in memory on startup to prevent any of it from being swapped
 REM out.
-set JAVA_OPTS=%JAVA_OPTS% -Xms%FESS_MIN_MEM% -Xmx%FESS_MAX_MEM%
-set JAVA_OPTS=%JAVA_OPTS% -XX:MaxMetaspaceSize=256m -XX:CompressedClassSpaceSize=32m
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Xms%FESS_MIN_MEM% -Xmx%FESS_MAX_MEM%
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:MaxMetaspaceSize=256m -XX:CompressedClassSpaceSize=32m
 
 REM new generation
 if NOT "%FESS_HEAP_NEWSIZE%" == "" (
-set JAVA_OPTS=%JAVA_OPTS% -Xmn%FESS_HEAP_NEWSIZE%
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Xmn%FESS_HEAP_NEWSIZE%
 )
 
 REM max direct memory
 if NOT "%FESS_DIRECT_SIZE%" == "" (
-set JAVA_OPTS=%JAVA_OPTS% -XX:MaxDirectMemorySize=%FESS_DIRECT_SIZE%
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:MaxDirectMemorySize=%FESS_DIRECT_SIZE%
 )
 
 REM set to headless, just in case
-set JAVA_OPTS=%JAVA_OPTS% -Djava.awt.headless=true
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Djava.awt.headless=true
 
 REM maximum # keep-alive connections to maintain at once
-set JAVA_OPTS=%JAVA_OPTS% -Dhttp.maxConnections=20
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dhttp.maxConnections=20
 
 REM Force the JVM to use IPv4 stack
 if NOT "%FESS_USE_IPV4%" == "" (
-set JAVA_OPTS=%JAVA_OPTS% -Djava.net.preferIPv4Stack=true
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Djava.net.preferIPv4Stack=true
 )
 
-set JAVA_OPTS=%JAVA_OPTS% -Djna.nosys=true
-set JAVA_OPTS=%JAVA_OPTS% -Djdk.io.permissionsUseCanonicalPath=true
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Djna.nosys=true
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Djdk.io.permissionsUseCanonicalPath=true
 
-set JAVA_OPTS=%JAVA_OPTS% -XX:+UseG1GC
-set JAVA_OPTS=%JAVA_OPTS% -XX:InitiatingHeapOccupancyPercent=75
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:+UseG1GC
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:InitiatingHeapOccupancyPercent=75
 
-set JAVA_OPTS=%JAVA_OPTS% -Dio.netty.noUnsafe=true
-set JAVA_OPTS=%JAVA_OPTS% -Dio.netty.noKeySetOptimization=true
-set JAVA_OPTS=%JAVA_OPTS% -Dio.netty.recycler.maxCapacityPerThread=0
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dio.netty.noUnsafe=true
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dio.netty.noKeySetOptimization=true
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dio.netty.recycler.maxCapacityPerThread=0
 
-set JAVA_OPTS=%JAVA_OPTS% -Dlog4j.shutdownHookEnabled=false
-set JAVA_OPTS=%JAVA_OPTS% -Dlog4j2.disable.jmx=true
-set JAVA_OPTS=%JAVA_OPTS% -Dlog4j.skipJansi=true
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dlog4j.shutdownHookEnabled=false
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dlog4j2.disable.jmx=true
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dlog4j.skipJansi=true
 
 REM SSL truststore for certificate validation over https
-REM JAVA_OPTS=%JAVA_OPTS% -Djavax.net.ssl.trustStore=/tech/elastic/config/truststore.jks
-REM JAVA_OPTS=%JAVA_OPTS% -Djavax.net.ssl.trustStorePassword=changeit
+REM FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Djavax.net.ssl.trustStore=/tech/elastic/config/truststore.jks
+REM FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Djavax.net.ssl.trustStorePassword=changeit
 
-if NOT "%FESS_USE_GC_LOGGING%" == "" set JAVA_OPTS=%JAVA_OPTS% -XX:+PrintGCDetails
-if NOT "%FESS_USE_GC_LOGGING%" == "" set JAVA_OPTS=%JAVA_OPTS% -XX:+PrintGCTimeStamps
-if NOT "%FESS_USE_GC_LOGGING%" == "" set JAVA_OPTS=%JAVA_OPTS% -XX:+PrintGCDateStamps
-if NOT "%FESS_USE_GC_LOGGING%" == "" set JAVA_OPTS=%JAVA_OPTS% -XX:+PrintClassHistogram
-if NOT "%FESS_USE_GC_LOGGING%" == "" set JAVA_OPTS=%JAVA_OPTS% -XX:+PrintTenuringDistribution
-if NOT "%FESS_USE_GC_LOGGING%" == "" set JAVA_OPTS=%JAVA_OPTS% -XX:+PrintGCApplicationStoppedTime
-if NOT "%FESS_USE_GC_LOGGING%" == "" set JAVA_OPTS=%JAVA_OPTS% -Xloggc:%FESS_HOME%/logs/gc.log
+if NOT "%FESS_USE_GC_LOGGING%" == "" set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:+PrintGCDetails
+if NOT "%FESS_USE_GC_LOGGING%" == "" set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:+PrintGCTimeStamps
+if NOT "%FESS_USE_GC_LOGGING%" == "" set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:+PrintGCDateStamps
+if NOT "%FESS_USE_GC_LOGGING%" == "" set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:+PrintClassHistogram
+if NOT "%FESS_USE_GC_LOGGING%" == "" set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:+PrintTenuringDistribution
+if NOT "%FESS_USE_GC_LOGGING%" == "" set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:+PrintGCApplicationStoppedTime
+if NOT "%FESS_USE_GC_LOGGING%" == "" set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Xloggc:%FESS_HOME%/logs/gc.log
 
 REM Causes the JVM to dump its heap on OutOfMemory.
-REM set JAVA_OPTS=%JAVA_OPTS% -XX:+HeapDumpOnOutOfMemoryError
+REM set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:+HeapDumpOnOutOfMemoryError
 REM The path to the heap dump location, note directory must exists and have enough
 REM space for a full heap dump.
-REM JAVA_OPTS=%JAVA_OPTS% -XX:HeapDumpPath=%FESS_HOME%/logs/heapdump.hprof
+REM FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:HeapDumpPath=%FESS_HOME%/logs/heapdump.hprof
 
 REM Disables explicit GC
-set JAVA_OPTS=%JAVA_OPTS% -XX:+DisableExplicitGC
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -XX:+DisableExplicitGC
 
 REM Ensure UTF-8 encoding by default (e.g. filenames)
-set JAVA_OPTS=%JAVA_OPTS% -Dfile.encoding=UTF-8
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dfile.encoding=UTF-8
 
 REM Use Groovy ClassValue
-set JAVA_OPTS=%JAVA_OPTS% -Dgroovy.use.classvalue=true
+set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dgroovy.use.classvalue=true
 
 REM Application Configuration
 set APP_NAME=fess
diff --git a/src/main/assemblies/files/fess.in.sh b/src/main/assemblies/files/fess.in.sh
index 4dd338c38..3958b0737 100755
--- a/src/main/assemblies/files/fess.in.sh
+++ b/src/main/assemblies/files/fess.in.sh
@@ -2,6 +2,13 @@
 
 FESS_CLASSPATH=$FESS_HOME/lib/classes
 
+# JAVA_OPTS is not a built-in JVM mechanism but some people think it is so we
+# warn them that we are not observing the value of $JAVA_OPTS
+if [ ! -z "$JAVA_OPTS" ]; then
+  echo -n "warning: ignoring JAVA_OPTS=$JAVA_OPTS; "
+  echo "pass JVM parameters via FESS_JAVA_OPTS"
+fi
+
 if [ "x$FESS_MIN_MEM" = "x" ]; then
     FESS_MIN_MEM=256m
 fi
@@ -18,72 +25,72 @@ fi
 #FESS_DICTIONARY_PATH=/var/lib/elasticsearch/config/
 
 # SSL truststore for certificate validation over https
-#JAVA_OPTS="$JAVA_OPTS -Djavax.net.ssl.trustStore=/tech/elastic/config/truststore.jks"
-#JAVA_OPTS="$JAVA_OPTS -Djavax.net.ssl.trustStorePassword=changeit"
+#FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Djavax.net.ssl.trustStore=/tech/elastic/config/truststore.jks"
+#FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Djavax.net.ssl.trustStorePassword=changeit"
 
 # min and max heap sizes should be set to the same value to avoid
 # stop-the-world GC pauses during resize, and so that we can lock the
 # heap in memory on startup to prevent any of it from being swapped
 # out.
-JAVA_OPTS="$JAVA_OPTS -Xms${FESS_MIN_MEM}"
-JAVA_OPTS="$JAVA_OPTS -Xmx${FESS_MAX_MEM}"
-JAVA_OPTS="$JAVA_OPTS -XX:MaxMetaspaceSize=256m -XX:CompressedClassSpaceSize=32m"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Xms${FESS_MIN_MEM}"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Xmx${FESS_MAX_MEM}"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:MaxMetaspaceSize=256m -XX:CompressedClassSpaceSize=32m"
 
 # new generation
 if [ "x$FESS_HEAP_NEWSIZE" != "x" ]; then
-    JAVA_OPTS="$JAVA_OPTS -Xmn${FESS_HEAP_NEWSIZE}"
+    FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Xmn${FESS_HEAP_NEWSIZE}"
 fi
 
 # set to headless, just in case
-JAVA_OPTS="$JAVA_OPTS -Djava.awt.headless=true"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Djava.awt.headless=true"
 
 # maximum # keep-alive connections to maintain at once
-JAVA_OPTS="$JAVA_OPTS -Dhttp.maxConnections=20"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Dhttp.maxConnections=20"
 
 # Force the JVM to use IPv4 stack
 if [ "x$FESS_USE_IPV4" != "x" ]; then
-  JAVA_OPTS="$JAVA_OPTS -Djava.net.preferIPv4Stack=true"
+  FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Djava.net.preferIPv4Stack=true"
 fi
 
-JAVA_OPTS="$JAVA_OPTS -Djna.nosys=true"
-JAVA_OPTS="$JAVA_OPTS -Djdk.io.permissionsUseCanonicalPath=true"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Djna.nosys=true"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Djdk.io.permissionsUseCanonicalPath=true"
 
-JAVA_OPTS="$JAVA_OPTS -XX:+UseG1GC"
-JAVA_OPTS="$JAVA_OPTS -XX:InitiatingHeapOccupancyPercent=75"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:+UseG1GC"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:InitiatingHeapOccupancyPercent=75"
 
-JAVA_OPTS="$JAVA_OPTS -Dio.netty.noUnsafe=true"
-JAVA_OPTS="$JAVA_OPTS -Dio.netty.noKeySetOptimization=true"
-JAVA_OPTS="$JAVA_OPTS -Dio.netty.recycler.maxCapacityPerThread=0"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Dio.netty.noUnsafe=true"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Dio.netty.noKeySetOptimization=true"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Dio.netty.recycler.maxCapacityPerThread=0"
 
-JAVA_OPTS="$JAVA_OPTS -Dlog4j.shutdownHookEnabled=false"
-JAVA_OPTS="$JAVA_OPTS -Dlog4j2.disable.jmx=true"
-JAVA_OPTS="$JAVA_OPTS -Dlog4j.skipJansi=true"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Dlog4j.shutdownHookEnabled=false"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Dlog4j2.disable.jmx=true"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Dlog4j.skipJansi=true"
 
 # GC logging options
 if [ "x$FESS_USE_GC_LOGGING" != "x" ]; then
-  JAVA_OPTS="$JAVA_OPTS -XX:+PrintGCDetails"
-  JAVA_OPTS="$JAVA_OPTS -XX:+PrintGCTimeStamps"
-  JAVA_OPTS="$JAVA_OPTS -XX:+PrintGCDateStamps"
-  JAVA_OPTS="$JAVA_OPTS -XX:+PrintClassHistogram"
-  JAVA_OPTS="$JAVA_OPTS -XX:+PrintTenuringDistribution"
-  JAVA_OPTS="$JAVA_OPTS -XX:+PrintGCApplicationStoppedTime"
-  JAVA_OPTS="$JAVA_OPTS -Xloggc:/var/log/elasticsearch/gc.log"
+  FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:+PrintGCDetails"
+  FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:+PrintGCTimeStamps"
+  FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:+PrintGCDateStamps"
+  FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:+PrintClassHistogram"
+  FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:+PrintTenuringDistribution"
+  FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:+PrintGCApplicationStoppedTime"
+  FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Xloggc:/var/log/elasticsearch/gc.log"
 fi
 
 # Causes the JVM to dump its heap on OutOfMemory.
-#JAVA_OPTS="$JAVA_OPTS -XX:+HeapDumpOnOutOfMemoryError"
+#FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:+HeapDumpOnOutOfMemoryError"
 # The path to the heap dump location, note directory must exists and have enough
 # space for a full heap dump.
-#JAVA_OPTS="$JAVA_OPTS -XX:HeapDumpPath=$FESS_HOME/logs/heapdump.hprof"
+#FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:HeapDumpPath=$FESS_HOME/logs/heapdump.hprof"
 
 # Disables explicit GC
-JAVA_OPTS="$JAVA_OPTS -XX:+DisableExplicitGC"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:+DisableExplicitGC"
 
 # Ensure UTF-8 encoding by default (e.g. filenames)
-JAVA_OPTS="$JAVA_OPTS -Dfile.encoding=UTF-8"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Dfile.encoding=UTF-8"
 
 # Use Groovy ClassValue
-JAVA_OPTS="$JAVA_OPTS -Dgroovy.use.classvalue=true"
+FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Dgroovy.use.classvalue=true"
 
 # Application Configuration
 if [ "x$APP_NAME" = "x" ]; then