fixed a crash when /usr/libexec/java_home returns no JVMs (tofi86#93)

Author: tofi86

CHANGELOG.md

@@ -6,6 +6,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 
+## [Unreleased]
+### Fixed
+- Fixed a crash when `/usr/libexec/java_home` returns no JVMs (#93)
+
+
 ## [3.1.0] - 2021-01-07
 ### Added
 - Support for macOS 11.0 "Big Sur" (#91)

src/universalJavaApplicationStub

@@ -11,8 +11,8 @@
 #                                                                                #
 # @author    Tobias Fischer                                                      #
 # @url       https://github.com/tofi86/universalJavaApplicationStub              #
-# @date      2021-01-07                                                          #
-# @version   3.1.0                                                               #
+# @date      2021-02-03                                                          #
+# @version   3.1.1                                                               #
 #                                                                                #
 ##################################################################################
 #                                                                                #
@@ -576,15 +576,18 @@ if [ -z "${JAVACMD}" ] || [ ! -x "${JAVACMD}" ] ; then
 	javaCounter=$(/usr/libexec/PlistBuddy -c "Print" /dev/stdin <<< $javaXml | grep "Dict" | wc -l | tr -d ' ')
 
 	# iterate over all Dict entries
-	for idx in $(seq 0 $((javaCounter - 1)))
-	do
-		version=$(/usr/libexec/PlistBuddy -c "print :$idx:JVMVersion" /dev/stdin <<< $javaXml)
-		path=$(/usr/libexec/PlistBuddy -c "print :$idx:JVMHomePath" /dev/stdin <<< $javaXml)
-		path+="/bin/java"
-		allJVMs+=("$version:$path")
-	done
-	# unset for loop variables
-	unset version path
+	# but only if there are any JVMs at all (#93)
+	if [ "$javaCounter" -gt "0" ] ; then
+		for idx in $(seq 0 $((javaCounter - 1)))
+		do
+			version=$(/usr/libexec/PlistBuddy -c "print :$idx:JVMVersion" /dev/stdin <<< $javaXml)
+			path=$(/usr/libexec/PlistBuddy -c "print :$idx:JVMHomePath" /dev/stdin <<< $javaXml)
+			path+="/bin/java"
+			allJVMs+=("$version:$path")
+		done
+		# unset for loop variables
+		unset version path
+	fi
 
 	# add SDKMAN! java versions (#95)
 	if [ -d ~/.sdkman/candidates/java/ ] ; then