Update Maven wrapper to 3.9.3.

Change-Id: Ib6603736b14853f7c340f7f0b766fd5b900088f6
diff --git a/mvnw b/mvnw
index 41c0f0c..8d937f4 100755
--- a/mvnw
+++ b/mvnw
@@ -19,7 +19,7 @@
 # ----------------------------------------------------------------------------
 
 # ----------------------------------------------------------------------------
-# Maven Start Up Batch script
+# Apache Maven Wrapper startup batch script, version 3.2.0
 #
 # Required ENV vars:
 # ------------------
@@ -27,7 +27,6 @@
 #
 # Optional ENV vars
 # -----------------
-#   M2_HOME - location of maven2's installed home dir
 #   MAVEN_OPTS - parameters passed to the Java VM when running Maven
 #     e.g. to debug Maven itself, use
 #       set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
@@ -36,6 +35,10 @@
 
 if [ -z "$MAVEN_SKIP_RC" ] ; then
 
+  if [ -f /usr/local/etc/mavenrc ] ; then
+    . /usr/local/etc/mavenrc
+  fi
+
   if [ -f /etc/mavenrc ] ; then
     . /etc/mavenrc
   fi
@@ -50,7 +53,7 @@
 cygwin=false;
 darwin=false;
 mingw=false
-case "`uname`" in
+case "$(uname)" in
   CYGWIN*) cygwin=true ;;
   MINGW*) mingw=true;;
   Darwin*) darwin=true
@@ -58,9 +61,9 @@
     # See https://developer.apple.com/library/mac/qa/qa1170/_index.html
     if [ -z "$JAVA_HOME" ]; then
       if [ -x "/usr/libexec/java_home" ]; then
-        export JAVA_HOME="`/usr/libexec/java_home`"
+        JAVA_HOME="$(/usr/libexec/java_home)"; export JAVA_HOME
       else
-        export JAVA_HOME="/Library/Java/Home"
+        JAVA_HOME="/Library/Java/Home"; export JAVA_HOME
       fi
     fi
     ;;
@@ -68,68 +71,38 @@
 
 if [ -z "$JAVA_HOME" ] ; then
   if [ -r /etc/gentoo-release ] ; then
-    JAVA_HOME=`java-config --jre-home`
+    JAVA_HOME=$(java-config --jre-home)
   fi
 fi
 
-if [ -z "$M2_HOME" ] ; then
-  ## resolve links - $0 may be a link to maven's home
-  PRG="$0"
-
-  # need this for relative symlinks
-  while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-      PRG="$link"
-    else
-      PRG="`dirname "$PRG"`/$link"
-    fi
-  done
-
-  saveddir=`pwd`
-
-  M2_HOME=`dirname "$PRG"`/..
-
-  # make it fully qualified
-  M2_HOME=`cd "$M2_HOME" && pwd`
-
-  cd "$saveddir"
-  # echo Using m2 at $M2_HOME
-fi
-
 # For Cygwin, ensure paths are in UNIX format before anything is touched
 if $cygwin ; then
-  [ -n "$M2_HOME" ] &&
-    M2_HOME=`cygpath --unix "$M2_HOME"`
   [ -n "$JAVA_HOME" ] &&
-    JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
+    JAVA_HOME=$(cygpath --unix "$JAVA_HOME")
   [ -n "$CLASSPATH" ] &&
-    CLASSPATH=`cygpath --path --unix "$CLASSPATH"`
+    CLASSPATH=$(cygpath --path --unix "$CLASSPATH")
 fi
 
 # For Mingw, ensure paths are in UNIX format before anything is touched
 if $mingw ; then
-  [ -n "$M2_HOME" ] &&
-    M2_HOME="`(cd "$M2_HOME"; pwd)`"
-  [ -n "$JAVA_HOME" ] &&
-    JAVA_HOME="`(cd "$JAVA_HOME"; pwd)`"
+  [ -n "$JAVA_HOME" ] && [ -d "$JAVA_HOME" ] &&
+    JAVA_HOME="$(cd "$JAVA_HOME" || (echo "cannot cd into $JAVA_HOME."; exit 1); pwd)"
 fi
 
 if [ -z "$JAVA_HOME" ]; then
-  javaExecutable="`which javac`"
-  if [ -n "$javaExecutable" ] && ! [ "`expr \"$javaExecutable\" : '\([^ ]*\)'`" = "no" ]; then
+  javaExecutable="$(which javac)"
+  if [ -n "$javaExecutable" ] && ! [ "$(expr "\"$javaExecutable\"" : '\([^ ]*\)')" = "no" ]; then
     # readlink(1) is not available as standard on Solaris 10.
-    readLink=`which readlink`
-    if [ ! `expr "$readLink" : '\([^ ]*\)'` = "no" ]; then
+    readLink=$(which readlink)
+    if [ ! "$(expr "$readLink" : '\([^ ]*\)')" = "no" ]; then
       if $darwin ; then
-        javaHome="`dirname \"$javaExecutable\"`"
-        javaExecutable="`cd \"$javaHome\" && pwd -P`/javac"
+        javaHome="$(dirname "\"$javaExecutable\"")"
+        javaExecutable="$(cd "\"$javaHome\"" && pwd -P)/javac"
       else
-        javaExecutable="`readlink -f \"$javaExecutable\"`"
+        javaExecutable="$(readlink -f "\"$javaExecutable\"")"
       fi
-      javaHome="`dirname \"$javaExecutable\"`"
-      javaHome=`expr "$javaHome" : '\(.*\)/bin'`
+      javaHome="$(dirname "\"$javaExecutable\"")"
+      javaHome=$(expr "$javaHome" : '\(.*\)/bin')
       JAVA_HOME="$javaHome"
       export JAVA_HOME
     fi
@@ -145,7 +118,7 @@
       JAVACMD="$JAVA_HOME/bin/java"
     fi
   else
-    JAVACMD="`which java`"
+    JAVACMD="$(\unset -f command 2>/dev/null; \command -v java)"
   fi
 fi
 
@@ -159,12 +132,9 @@
   echo "Warning: JAVA_HOME environment variable is not set."
 fi
 
-CLASSWORLDS_LAUNCHER=org.codehaus.plexus.classworlds.launcher.Launcher
-
 # traverses directory structure from process work directory to filesystem root
 # first directory with .mvn subdirectory is considered project base directory
 find_maven_basedir() {
-
   if [ -z "$1" ]
   then
     echo "Path not specified to find_maven_basedir"
@@ -180,96 +150,99 @@
     fi
     # workaround for JBEAP-8937 (on Solaris 10/Sparc)
     if [ -d "${wdir}" ]; then
-      wdir=`cd "$wdir/.."; pwd`
+      wdir=$(cd "$wdir/.." || exit 1; pwd)
     fi
     # end of workaround
   done
-  echo "${basedir}"
+  printf '%s' "$(cd "$basedir" || exit 1; pwd)"
 }
 
 # concatenates all lines of a file
 concat_lines() {
   if [ -f "$1" ]; then
-    echo "$(tr -s '\n' ' ' < "$1")"
+    # Remove \r in case we run on Windows within Git Bash
+    # and check out the repository with auto CRLF management
+    # enabled. Otherwise, we may read lines that are delimited with
+    # \r\n and produce $'-Xarg\r' rather than -Xarg due to word
+    # splitting rules.
+    tr -s '\r\n' ' ' < "$1"
   fi
 }
 
-BASE_DIR=`find_maven_basedir "$(pwd)"`
+log() {
+  if [ "$MVNW_VERBOSE" = true ]; then
+    printf '%s\n' "$1"
+  fi
+}
+
+BASE_DIR=$(find_maven_basedir "$(dirname "$0")")
 if [ -z "$BASE_DIR" ]; then
   exit 1;
 fi
 
+MAVEN_PROJECTBASEDIR=${MAVEN_BASEDIR:-"$BASE_DIR"}; export MAVEN_PROJECTBASEDIR
+log "$MAVEN_PROJECTBASEDIR"
+
 ##########################################################################################
 # Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
 # This allows using the maven wrapper in projects that prohibit checking in binary data.
 ##########################################################################################
-if [ -r "$BASE_DIR/.mvn/wrapper/maven-wrapper.jar" ]; then
-    if [ "$MVNW_VERBOSE" = true ]; then
-      echo "Found .mvn/wrapper/maven-wrapper.jar"
-    fi
+wrapperJarPath="$MAVEN_PROJECTBASEDIR/.mvn/wrapper/maven-wrapper.jar"
+if [ -r "$wrapperJarPath" ]; then
+    log "Found $wrapperJarPath"
 else
-    if [ "$MVNW_VERBOSE" = true ]; then
-      echo "Couldn't find .mvn/wrapper/maven-wrapper.jar, downloading it ..."
-    fi
+    log "Couldn't find $wrapperJarPath, downloading it ..."
+
     if [ -n "$MVNW_REPOURL" ]; then
-      jarUrl="$MVNW_REPOURL/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+      wrapperUrl="$MVNW_REPOURL/org/apache/maven/wrapper/maven-wrapper/3.2.0/maven-wrapper-3.2.0.jar"
     else
-      jarUrl="https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+      wrapperUrl="https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.2.0/maven-wrapper-3.2.0.jar"
     fi
-    while IFS="=" read key value; do
-      case "$key" in (wrapperUrl) jarUrl="$value"; break ;;
+    while IFS="=" read -r key value; do
+      # Remove '\r' from value to allow usage on windows as IFS does not consider '\r' as a separator ( considers space, tab, new line ('\n'), and custom '=' )
+      safeValue=$(echo "$value" | tr -d '\r')
+      case "$key" in (wrapperUrl) wrapperUrl="$safeValue"; break ;;
       esac
-    done < "$BASE_DIR/.mvn/wrapper/maven-wrapper.properties"
-    if [ "$MVNW_VERBOSE" = true ]; then
-      echo "Downloading from: $jarUrl"
-    fi
-    wrapperJarPath="$BASE_DIR/.mvn/wrapper/maven-wrapper.jar"
+    done < "$MAVEN_PROJECTBASEDIR/.mvn/wrapper/maven-wrapper.properties"
+    log "Downloading from: $wrapperUrl"
+
     if $cygwin; then
-      wrapperJarPath=`cygpath --path --windows "$wrapperJarPath"`
+      wrapperJarPath=$(cygpath --path --windows "$wrapperJarPath")
     fi
 
     if command -v wget > /dev/null; then
-        if [ "$MVNW_VERBOSE" = true ]; then
-          echo "Found wget ... using wget"
-        fi
+        log "Found wget ... using wget"
+        [ "$MVNW_VERBOSE" = true ] && QUIET="" || QUIET="--quiet"
         if [ -z "$MVNW_USERNAME" ] || [ -z "$MVNW_PASSWORD" ]; then
-            wget "$jarUrl" -O "$wrapperJarPath"
+            wget $QUIET "$wrapperUrl" -O "$wrapperJarPath" || rm -f "$wrapperJarPath"
         else
-            wget --http-user=$MVNW_USERNAME --http-password=$MVNW_PASSWORD "$jarUrl" -O "$wrapperJarPath"
+            wget $QUIET --http-user="$MVNW_USERNAME" --http-password="$MVNW_PASSWORD" "$wrapperUrl" -O "$wrapperJarPath" || rm -f "$wrapperJarPath"
         fi
     elif command -v curl > /dev/null; then
-        if [ "$MVNW_VERBOSE" = true ]; then
-          echo "Found curl ... using curl"
-        fi
+        log "Found curl ... using curl"
+        [ "$MVNW_VERBOSE" = true ] && QUIET="" || QUIET="--silent"
         if [ -z "$MVNW_USERNAME" ] || [ -z "$MVNW_PASSWORD" ]; then
-            curl -o "$wrapperJarPath" "$jarUrl" -f
+            curl $QUIET -o "$wrapperJarPath" "$wrapperUrl" -f -L || rm -f "$wrapperJarPath"
         else
-            curl --user $MVNW_USERNAME:$MVNW_PASSWORD -o "$wrapperJarPath" "$jarUrl" -f
+            curl $QUIET --user "$MVNW_USERNAME:$MVNW_PASSWORD" -o "$wrapperJarPath" "$wrapperUrl" -f -L || rm -f "$wrapperJarPath"
         fi
-
     else
-        if [ "$MVNW_VERBOSE" = true ]; then
-          echo "Falling back to using Java to download"
-        fi
-        javaClass="$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.java"
+        log "Falling back to using Java to download"
+        javaSource="$MAVEN_PROJECTBASEDIR/.mvn/wrapper/MavenWrapperDownloader.java"
+        javaClass="$MAVEN_PROJECTBASEDIR/.mvn/wrapper/MavenWrapperDownloader.class"
         # For Cygwin, switch paths to Windows format before running javac
         if $cygwin; then
-          javaClass=`cygpath --path --windows "$javaClass"`
+          javaSource=$(cygpath --path --windows "$javaSource")
+          javaClass=$(cygpath --path --windows "$javaClass")
         fi
-        if [ -e "$javaClass" ]; then
-            if [ ! -e "$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.class" ]; then
-                if [ "$MVNW_VERBOSE" = true ]; then
-                  echo " - Compiling MavenWrapperDownloader.java ..."
-                fi
-                # Compiling the Java class
-                ("$JAVA_HOME/bin/javac" "$javaClass")
+        if [ -e "$javaSource" ]; then
+            if [ ! -e "$javaClass" ]; then
+                log " - Compiling MavenWrapperDownloader.java ..."
+                ("$JAVA_HOME/bin/javac" "$javaSource")
             fi
-            if [ -e "$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.class" ]; then
-                # Running the downloader
-                if [ "$MVNW_VERBOSE" = true ]; then
-                  echo " - Running MavenWrapperDownloader.java ..."
-                fi
-                ("$JAVA_HOME/bin/java" -cp .mvn/wrapper MavenWrapperDownloader "$MAVEN_PROJECTBASEDIR")
+            if [ -e "$javaClass" ]; then
+                log " - Running MavenWrapperDownloader.java ..."
+                ("$JAVA_HOME/bin/java" -cp .mvn/wrapper MavenWrapperDownloader "$wrapperUrl" "$wrapperJarPath") || rm -f "$wrapperJarPath"
             fi
         fi
     fi
@@ -278,33 +251,58 @@
 # End of extension
 ##########################################################################################
 
-export MAVEN_PROJECTBASEDIR=${MAVEN_BASEDIR:-"$BASE_DIR"}
-if [ "$MVNW_VERBOSE" = true ]; then
-  echo $MAVEN_PROJECTBASEDIR
+# If specified, validate the SHA-256 sum of the Maven wrapper jar file
+wrapperSha256Sum=""
+while IFS="=" read -r key value; do
+  case "$key" in (wrapperSha256Sum) wrapperSha256Sum=$value; break ;;
+  esac
+done < "$MAVEN_PROJECTBASEDIR/.mvn/wrapper/maven-wrapper.properties"
+if [ -n "$wrapperSha256Sum" ]; then
+  wrapperSha256Result=false
+  if command -v sha256sum > /dev/null; then
+    if echo "$wrapperSha256Sum  $wrapperJarPath" | sha256sum -c > /dev/null 2>&1; then
+      wrapperSha256Result=true
+    fi
+  elif command -v shasum > /dev/null; then
+    if echo "$wrapperSha256Sum  $wrapperJarPath" | shasum -a 256 -c > /dev/null 2>&1; then
+      wrapperSha256Result=true
+    fi
+  else
+    echo "Checksum validation was requested but neither 'sha256sum' or 'shasum' are available."
+    echo "Please install either command, or disable validation by removing 'wrapperSha256Sum' from your maven-wrapper.properties."
+    exit 1
+  fi
+  if [ $wrapperSha256Result = false ]; then
+    echo "Error: Failed to validate Maven wrapper SHA-256, your Maven wrapper might be compromised." >&2
+    echo "Investigate or delete $wrapperJarPath to attempt a clean download." >&2
+    echo "If you updated your Maven version, you need to update the specified wrapperSha256Sum property." >&2
+    exit 1
+  fi
 fi
+
 MAVEN_OPTS="$(concat_lines "$MAVEN_PROJECTBASEDIR/.mvn/jvm.config") $MAVEN_OPTS"
 
 # For Cygwin, switch paths to Windows format before running java
 if $cygwin; then
-  [ -n "$M2_HOME" ] &&
-    M2_HOME=`cygpath --path --windows "$M2_HOME"`
   [ -n "$JAVA_HOME" ] &&
-    JAVA_HOME=`cygpath --path --windows "$JAVA_HOME"`
+    JAVA_HOME=$(cygpath --path --windows "$JAVA_HOME")
   [ -n "$CLASSPATH" ] &&
-    CLASSPATH=`cygpath --path --windows "$CLASSPATH"`
+    CLASSPATH=$(cygpath --path --windows "$CLASSPATH")
   [ -n "$MAVEN_PROJECTBASEDIR" ] &&
-    MAVEN_PROJECTBASEDIR=`cygpath --path --windows "$MAVEN_PROJECTBASEDIR"`
+    MAVEN_PROJECTBASEDIR=$(cygpath --path --windows "$MAVEN_PROJECTBASEDIR")
 fi
 
 # Provide a "standardized" way to retrieve the CLI args that will
 # work with both Windows and non-Windows executions.
-MAVEN_CMD_LINE_ARGS="$MAVEN_CONFIG $@"
+MAVEN_CMD_LINE_ARGS="$MAVEN_CONFIG $*"
 export MAVEN_CMD_LINE_ARGS
 
 WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
 
+# shellcheck disable=SC2086 # safe args
 exec "$JAVACMD" \
   $MAVEN_OPTS \
+  $MAVEN_DEBUG_OPTS \
   -classpath "$MAVEN_PROJECTBASEDIR/.mvn/wrapper/maven-wrapper.jar" \
-  "-Dmaven.home=${M2_HOME}" "-Dmaven.multiModuleProjectDirectory=${MAVEN_PROJECTBASEDIR}" \
+  "-Dmaven.multiModuleProjectDirectory=${MAVEN_PROJECTBASEDIR}" \
   ${WRAPPER_LAUNCHER} $MAVEN_CONFIG "$@"