Update Maven wrapper to 3.9.3.

Change-Id: Ib6603736b14853f7c340f7f0b766fd5b900088f6
diff --git a/.mvn/wrapper/MavenWrapperDownloader.java b/.mvn/wrapper/MavenWrapperDownloader.java
deleted file mode 100644
index b901097..0000000
--- a/.mvn/wrapper/MavenWrapperDownloader.java
+++ /dev/null
@@ -1,117 +0,0 @@
-/*
- * Copyright 2007-present the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-import java.net.*;
-import java.io.*;
-import java.nio.channels.*;
-import java.util.Properties;
-
-public class MavenWrapperDownloader {
-
-    private static final String WRAPPER_VERSION = "0.5.6";
-    /**
-     * Default URL to download the maven-wrapper.jar from, if no 'downloadUrl' is provided.
-     */
-    private static final String DEFAULT_DOWNLOAD_URL = "https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/"
-        + WRAPPER_VERSION + "/maven-wrapper-" + WRAPPER_VERSION + ".jar";
-
-    /**
-     * Path to the maven-wrapper.properties file, which might contain a downloadUrl property to
-     * use instead of the default one.
-     */
-    private static final String MAVEN_WRAPPER_PROPERTIES_PATH =
-            ".mvn/wrapper/maven-wrapper.properties";
-
-    /**
-     * Path where the maven-wrapper.jar will be saved to.
-     */
-    private static final String MAVEN_WRAPPER_JAR_PATH =
-            ".mvn/wrapper/maven-wrapper.jar";
-
-    /**
-     * Name of the property which should be used to override the default download url for the wrapper.
-     */
-    private static final String PROPERTY_NAME_WRAPPER_URL = "wrapperUrl";
-
-    public static void main(String args[]) {
-        System.out.println("- Downloader started");
-        File baseDirectory = new File(args[0]);
-        System.out.println("- Using base directory: " + baseDirectory.getAbsolutePath());
-
-        // If the maven-wrapper.properties exists, read it and check if it contains a custom
-        // wrapperUrl parameter.
-        File mavenWrapperPropertyFile = new File(baseDirectory, MAVEN_WRAPPER_PROPERTIES_PATH);
-        String url = DEFAULT_DOWNLOAD_URL;
-        if(mavenWrapperPropertyFile.exists()) {
-            FileInputStream mavenWrapperPropertyFileInputStream = null;
-            try {
-                mavenWrapperPropertyFileInputStream = new FileInputStream(mavenWrapperPropertyFile);
-                Properties mavenWrapperProperties = new Properties();
-                mavenWrapperProperties.load(mavenWrapperPropertyFileInputStream);
-                url = mavenWrapperProperties.getProperty(PROPERTY_NAME_WRAPPER_URL, url);
-            } catch (IOException e) {
-                System.out.println("- ERROR loading '" + MAVEN_WRAPPER_PROPERTIES_PATH + "'");
-            } finally {
-                try {
-                    if(mavenWrapperPropertyFileInputStream != null) {
-                        mavenWrapperPropertyFileInputStream.close();
-                    }
-                } catch (IOException e) {
-                    // Ignore ...
-                }
-            }
-        }
-        System.out.println("- Downloading from: " + url);
-
-        File outputFile = new File(baseDirectory.getAbsolutePath(), MAVEN_WRAPPER_JAR_PATH);
-        if(!outputFile.getParentFile().exists()) {
-            if(!outputFile.getParentFile().mkdirs()) {
-                System.out.println(
-                        "- ERROR creating output directory '" + outputFile.getParentFile().getAbsolutePath() + "'");
-            }
-        }
-        System.out.println("- Downloading to: " + outputFile.getAbsolutePath());
-        try {
-            downloadFileFromURL(url, outputFile);
-            System.out.println("Done");
-            System.exit(0);
-        } catch (Throwable e) {
-            System.out.println("- Error downloading");
-            e.printStackTrace();
-            System.exit(1);
-        }
-    }
-
-    private static void downloadFileFromURL(String urlString, File destination) throws Exception {
-        if (System.getenv("MVNW_USERNAME") != null && System.getenv("MVNW_PASSWORD") != null) {
-            String username = System.getenv("MVNW_USERNAME");
-            char[] password = System.getenv("MVNW_PASSWORD").toCharArray();
-            Authenticator.setDefault(new Authenticator() {
-                @Override
-                protected PasswordAuthentication getPasswordAuthentication() {
-                    return new PasswordAuthentication(username, password);
-                }
-            });
-        }
-        URL website = new URL(urlString);
-        ReadableByteChannel rbc;
-        rbc = Channels.newChannel(website.openStream());
-        FileOutputStream fos = new FileOutputStream(destination);
-        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
-        fos.close();
-        rbc.close();
-    }
-
-}
diff --git a/.mvn/wrapper/maven-wrapper.jar b/.mvn/wrapper/maven-wrapper.jar
index 2cc7d4a..cb28b0e 100644
--- a/.mvn/wrapper/maven-wrapper.jar
+++ b/.mvn/wrapper/maven-wrapper.jar
Binary files differ
diff --git a/.mvn/wrapper/maven-wrapper.properties b/.mvn/wrapper/maven-wrapper.properties
index 642d572..6d3a566 100644
--- a/.mvn/wrapper/maven-wrapper.properties
+++ b/.mvn/wrapper/maven-wrapper.properties
@@ -1,2 +1,18 @@
-distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.zip
-wrapperUrl=https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.9.3/apache-maven-3.9.3-bin.zip
+wrapperUrl=https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.2.0/maven-wrapper-3.2.0.jar