Servlet to Take a heapdump or thread dump to be incorporated into an application

DumpServlet.java

package org.cloudfoundry.samples.music.debug;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.Writer;
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadInfo;
import java.lang.management.ThreadMXBean;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletResponse;

import com.sun.management.HotSpotDiagnosticMXBean;

@SuppressWarnings("serial")
public class DumpServlet extends HttpServlet {

	@Override
	public void service(ServletRequest req, ServletResponse res)
			throws ServletException, IOException {
		PrintWriter out = ((HttpServletResponse) res).getWriter();
		out.println("Dumping... live");
		String type = req.getParameter("type");

		if (null != type) {
			if (type.equals("heap")) {
				File dumpFile = new File(System.currentTimeMillis()+ ".hprof");
				out.println("Dumping heap to " + dumpFile.getCanonicalPath());
				HotSpotDiagnosticMXBean hotSpotDiagnosticMXBean = ManagementFactory
						.getPlatformMXBeans(HotSpotDiagnosticMXBean.class).get(0);
				hotSpotDiagnosticMXBean.dumpHeap(dumpFile.getAbsolutePath(),true);
				
			} else if (type.equals("thread")) {
				dumpStacks(out);
			}
			
		}

		out.flush();
		out.close();
	}

	public static void dumpStacks(PrintWriter out) throws IOException {
		ThreadMXBean mxBean = ManagementFactory.getThreadMXBean();
		ThreadInfo[] threadInfos = mxBean.getThreadInfo(
				mxBean.getAllThreadIds(), 0);
		Map<Long, ThreadInfo> threadInfoMap = new HashMap<Long, ThreadInfo>();
		for (ThreadInfo threadInfo : threadInfos) {
			threadInfoMap.put(threadInfo.getThreadId(), threadInfo);
		}

		// choose our dump-file
		File dumpFile = new File("stacks." + System.currentTimeMillis());
		out.println("Dumping Thread Info to " + dumpFile.getCanonicalPath());
		Writer writer = new BufferedWriter(new FileWriter(dumpFile));
		try {
			dumpTraces(mxBean, threadInfoMap, writer);
		} finally {
			writer.close();
		}
	}

	private static void dumpTraces(ThreadMXBean mxBean,
			Map<Long, ThreadInfo> threadInfoMap, Writer writer)
			throws IOException {
		Map<Thread, StackTraceElement[]> stacks = Thread.getAllStackTraces();
		writer.write("Dump of "
				+ stacks.size()
				+ " thread at "
				+ new SimpleDateFormat("yyyy/MM/dd HH:mm:ss z")
						.format(new Date(System.currentTimeMillis())) + "\n\n");
		for (Map.Entry<Thread, StackTraceElement[]> entry : stacks.entrySet()) {
			Thread thread = entry.getKey();
			writer.write("\"" + thread.getName() + "\" prio="
					+ thread.getPriority() + " tid=" + thread.getId() + " "
					+ thread.getState() + " "
					+ (thread.isDaemon() ? "deamon" : "worker") + "\n");
			ThreadInfo threadInfo = threadInfoMap.get(thread.getId());
			if (threadInfo != null) {
				writer.write("    native=" + threadInfo.isInNative()
						+ ", suspended=" + threadInfo.isSuspended()
						+ ", block=" + threadInfo.getBlockedCount() + ", wait="
						+ threadInfo.getWaitedCount() + "\n");
				writer.write("    lock="
						+ threadInfo.getLockName()
						+ " owned by "
						+ threadInfo.getLockOwnerName()
						+ " ("
						+ threadInfo.getLockOwnerId()
						+ "), cpu="
						+ (mxBean.getThreadCpuTime(threadInfo.getThreadId()) / 1000000L)
						+ ", user="
						+ (mxBean.getThreadUserTime(threadInfo.getThreadId()) / 1000000L)
						+ "\n");
			}
			for (StackTraceElement element : entry.getValue()) {
				writer.write("        ");
				writer.write(element.toString());
				writer.write("\n");
			}
			writer.write("\n");
		}
	}

}