Experimental: Support Gradle --parallel

This should be treated as experimental but with these changes it seems to build ok.

BUILD SUCCESSFUL

Total time: 5 mins 15.533 secs

It turns out that our sporadic Redis problems were fixed in a later version of Jedis.

The problem was that the `connection.subscribe()` exited immediately. When I started adding debug
logic, the problem went away (because I was using a newer versio of Jedis).

spring-data-redis 1.5.2 is updated to work with the 2.7.3 version of Jedis.

Polishing

spring-integration-test/src/main/java/org/springframework/integration/test/util/HeapDumper.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright 2015 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.springframework.integration.test.util;
+
+import java.io.File;
+import java.lang.management.ManagementFactory;
+
+import javax.management.MBeanServer;
+
+import com.sun.management.HotSpotDiagnosticMXBean;
+
+/**
+ * Use to take a heap dump programmatically. Useful to examine the heap when debugging
+ * sporadic test failures.
+ * <p>
+ * Usage: {@code HeapDumper.dumpHeap("/tmp/foo.hprof");}
+ * <p>
+ * If the file exists already, it will be replaced.
+ * <p>
+ * Courtesy:
+ * https://blogs.oracle.com/sundararajan/entry/programmatically_dumping_heap_from_java
+ * <pre>
+ * See https://docs.oracle.com/javase/8/docs/jre/api/management/extension/com/sun/management/HotSpotDiagnosticMXBean.html#dumpHeap-java.lang.String-boolean-
+ * </pre>
+ * @author Gary Russell
+ * @since 4.2
+ *
+ */
+public class HeapDumper {
+
+	// This is the name of the HotSpot Diagnostic MBean
+	private static final String HOTSPOT_BEAN_NAME = "com.sun.management:type=HotSpotDiagnostic";
+
+	// field to store the hotspot diagnostic MBean
+	private static volatile HotSpotDiagnosticMXBean hotspotMBean;
+
+	public static void dumpHeap(String fileName) {
+		dumpHeap(fileName, true);
+	}
+
+	public static void dumpHeap(String fileName, boolean live) {
+		File file = new File(fileName);
+		if (file.exists()) {
+			file.delete();
+		}
+		// initialize hotspot diagnostic MBean
+		initHotspotMBean();
+		try {
+			hotspotMBean.dumpHeap(fileName, live);
+		}
+		catch (RuntimeException re) {
+			throw re;
+		}
+		catch (Exception exp) {
+			throw new RuntimeException(exp);
+		}
+	}
+
+	// initialize the hotspot diagnostic MBean field
+	private static void initHotspotMBean() {
+		if (hotspotMBean == null) {
+			synchronized (Object.class) {
+				if (hotspotMBean == null) {
+					hotspotMBean = getHotspotMBean();
+				}
+			}
+		}
+	}
+
+	// get the hotspot diagnostic MBean from the
+	// platform MBean server
+	private static HotSpotDiagnosticMXBean getHotspotMBean() {
+		try {
+			MBeanServer server = ManagementFactory.getPlatformMBeanServer();
+			HotSpotDiagnosticMXBean bean = ManagementFactory.newPlatformMXBeanProxy(server, HOTSPOT_BEAN_NAME,
+					HotSpotDiagnosticMXBean.class);
+			return bean;
+		}
+		catch (RuntimeException re) {
+			throw re;
+		}
+		catch (Exception exp) {
+			throw new RuntimeException(exp);
+		}
+	}
+
+}