check for java version before updating

Signed-off-by: Markus Storm <markus.storm@gmx.net>

functions/menu.bash

@@ -31,6 +31,7 @@ Menu 50 provides options to backup and restore either your openHAB configuration
 show_main_menu() {
   local choice
   local version
+  local javaVersion
 
 
   choice=$(whiptail --title "openHABian Configuration Tool — $(get_git_revision)" --menu "Setup Options" 24 118 16 --cancel-button Exit --ok-button Execute \
@@ -72,8 +73,13 @@ show_main_menu() {
         whiptail --title "outdated OS" --msgbox "You are running a too old version of your Operating System.\\n\\nOpenHAB 4 and Java 17 require that you upgrade to Debian 11 (bullseye) first." 8 80
         return 255
     fi
+
+    javaVersion="$(java -version |& grep -m 1 -o "[0-9]\{0,3\}\.[0-9]\{0,3\}\.[0-9]\{0,3\}[\.+][0-9]\{0,3\}" | head -1|cut -d '.' -f1)"
     if [[ $(apt-cache madison openhab | head -n 1 | awk '{ print $3 }' | cut -d'.' -f1) = 4 ]]; then
-      update_config_java "17" && java_install "17"
+      if [[ $javaVersion -lt 17 ]] ; then
+        update_config_java "17"
+        java_install "17"
+      fi
     fi
     repo=$(apt-cache madison openhab | head -n 1 | awk '{ print $6 }' |cut -d'/' -f1)
     openhab_setup "openHAB" "${repo:-release}"