From 25b02f29a741aa659cb8e49ce1d4c85e43c72e84 Mon Sep 17 00:00:00 2001
From: Mark Paluch <mpaluch@pivotal.io>
Date: Mon, 10 Dec 2018 18:39:26 +0100
Subject: [PATCH] DATAES-515 - Override Elasticsearch's JarHell for tests.

---
 .../org/elasticsearch/bootstrap/JarHell.java  | 86 +++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 src/test/java/org/elasticsearch/bootstrap/JarHell.java

diff --git a/src/test/java/org/elasticsearch/bootstrap/JarHell.java b/src/test/java/org/elasticsearch/bootstrap/JarHell.java
new file mode 100644
index 000000000..5b7118fa7
--- /dev/null
+++ b/src/test/java/org/elasticsearch/bootstrap/JarHell.java
@@ -0,0 +1,86 @@
+/*
+ * Copyright 2018 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.
+ */
+
+package org.elasticsearch.bootstrap;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.util.Collections;
+import java.util.Set;
+import java.util.function.Consumer;
+
+/**
+ * No words – No words can describe this piece of code and why we cannot opt-in/opt-out from JarHell check.
+ * <p/>
+ * Elasticsearch wants to raise awareness if there are two classes with the exact same name (class name and package
+ * name) to avoid downstream issues. Turns out, in some case, such as Java 9 module descriptors, it's perfectly fine to
+ * have exactly same class names (such as {@code module-info.class}) yet JarHell goes awry and prevents startup.
+ * <p>
+ * This class is here to be loaded before ES's JarHell class and to anyone that wants to survive JarHell, leave it here
+ * or you will die a slow and painful death.
+ * <p>
+ * Oh, by the way: If Elasticsearch decides to upgrade JarHell with new method signatures, we should adapt to these.
+ *
+ * @author Mark Paluch
+ */
+public class JarHell {
+
+	private JarHell() {}
+
+	/**
+	 * Empty stub. Leave it here or you will die a slow and painful death.
+	 *
+	 * @param output
+	 * @throws IOException
+	 * @throws URISyntaxException
+	 */
+	public static void checkJarHell(Consumer<String> output) throws IOException, URISyntaxException {}
+
+	/**
+	 * Empty stub. Leave it here or you will die a slow and painful death.
+	 *
+	 * @return
+	 */
+	public static Set<URL> parseClassPath() {
+		return Collections.emptySet();
+	}
+
+	/**
+	 * Empty stub. Leave it here or you will die a slow and painful death.
+	 *
+	 * @param urls
+	 * @param output
+	 * @throws URISyntaxException
+	 * @throws IOException
+	 */
+	public static void checkJarHell(Set<URL> urls, Consumer<String> output) throws URISyntaxException, IOException {}
+
+	/**
+	 * Empty stub. Leave it here or you will die a slow and painful death.
+	 *
+	 * @param targetVersion
+	 */
+	public static void checkVersionFormat(String targetVersion) {}
+
+	/**
+	 * Empty stub. Leave it here or you will die a slow and painful death.
+	 *
+	 * @param resource
+	 * @param targetVersion
+	 */
+	public static void checkJavaVersion(String resource, String targetVersion) {}
+}