Main.java

package com.company;


import javax.management.MBeanServer;
import java.lang.management.ManagementFactory;
import java.lang.reflect.Method;

public class Main {


	private ThreadLocal<Foo> threadLocal = new ThreadLocal<>();

	public static void main(String[] args) {
		Main main = new Main();
		main.foo();
	}

	void foo() {
		String file = "HeapDump-" + System.currentTimeMillis() + ".hprof";

		leak();
		System.gc();

		new HeapDump().dumpHeap(file, true);
	}

	private void leak() {
		Foo value = new Foo();
		threadLocal.set(value);

//		threadLocal = null;            
//				threadLocal.remove();  
		threadLocal = new ThreadLocal<>();   
				threadLocal.remove();        
				
				
		System.gc();
		System.err.println(new byte[10_000_000]);
		System.gc();
		System.err.println(new byte[10_000_000]);
		System.gc();
		     

	}
	public static class Foo {
			byte[] b = new byte[10_000_000];
		}
		
	@SuppressWarnings("restriction")
	public static class HeapDump {
		// 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 Object hotspotMBean;

		/**
		 * Call this method from your application whenever you
		 * want to dump the heap snapshot into a file.
		 *
		 * @param fileName name of the heap dump file
		 * @param live     flag that tells whether to dump
		 *                 only the live objects
		 */
		static void dumpHeap(String fileName, boolean live) {
			// initialize hotspot diagnostic MBean
			initHotspotMBean();
			try {
				Class clazz = Class.forName("com.sun.management.HotSpotDiagnosticMXBean");
				Method m = clazz.getMethod("dumpHeap", String.class, boolean.class);
				m.invoke(hotspotMBean, 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 (HeapDump.class) {
					if (hotspotMBean == null) {
						hotspotMBean = getHotspotMBean();
					}
				}
			}
		}

		// get the hotspot diagnostic MBean from the
		// platform MBean server
		private static Object getHotspotMBean() {
			try {
				Class clazz = Class.forName("com.sun.management.HotSpotDiagnosticMXBean");
				MBeanServer server = ManagementFactory.getPlatformMBeanServer();
				Object bean =
						ManagementFactory.newPlatformMXBeanProxy(server,
								HOTSPOT_BEAN_NAME, clazz);
				return bean;
			} catch (RuntimeException re) {
				throw re;
			} catch (Exception exp) {
				throw new RuntimeException(exp);
			}
		}

		public static void main(String[] args) {
			// default heap dump file name
			String fileName = "heap.bin";
			// by default dump only the live objects
			boolean live = true;

			// simple command line options
			switch (args.length) {
				case 2:
					live = args[1].equals("true");
				case 1:
					fileName = args[0];
			}

			// dump the heap
			dumpHeap(fileName, live);
		}
	}

	
}