yuki-teraoka/threaddump_sample_Servlets.java

## threaddump_sample_Servlets.java
package com.techscore.sandbox;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Servlets {
    @WebServlet(name = "Index", urlPatterns = { "/" })
    public static class Index extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            resp.getWriter().print("<html><body><h1>Sandbox!</h1>" + "<a href=\"/NetworkIO\">NetworkIO</a><br>"
                    + "<a href=\"/DeadLock\">DeadLock</a><br>" + "<a href=\"/Regex\">Regex</a><br>");
        }
    }


    @WebServlet(name = "Sleep", urlPatterns = { "/Sleep" })
    public static class Sleep extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            try {
                Thread.sleep(10000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    @WebServlet(name = "NetworkIO", urlPatterns = { "/NetworkIO" })
    public static class NetworkIO extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            URL url = new URL("http://localhost:8080/Sleep");
            InputStream is = url.openConnection().getInputStream();
        }
    }

    @WebServlet(name = "DeadLock", urlPatterns = { "/DeadLock" })
    public static class DeadLock extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            Object obj1 = new Object();
            Object obj2 = new Object();

            new Thread(() -> {
                synchronized (obj1) {
                    sleep(500);
                    synchronized (obj2) {
                    }
                }
            }).start();

            new Thread(() -> {
                synchronized (obj2) {
                    sleep(500);
                    synchronized (obj1) {
                    }
                }
            }).start();
        }

        private void sleep(long millis) {
            try {
                Thread.sleep(millis);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    @WebServlet(name = "Regex", urlPatterns = { "/Regex" })
    public static class Regex extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            for (int i = 0; i < 50000000; i++) {
                "hogehoge".replaceAll("hoge", "fuga");
            }
            resp.getWriter().println("Done!");
        }
    }
}
	package com.techscore.sandbox;

	import java.io.IOException;
	import java.io.InputStream;
	import java.net.URL;
	import java.nio.ByteBuffer;
	import java.util.ArrayList;
	import java.util.List;
	import java.util.regex.Pattern;

	import javax.servlet.ServletException;
	import javax.servlet.annotation.WebServlet;
	import javax.servlet.http.HttpServlet;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;

	public class Servlets {
	@WebServlet(name = "Index", urlPatterns = { "/" })
	public static class Index extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	resp.getWriter().print("<html><body><h1>Sandbox!</h1>" + "<a href=\"/NetworkIO\">NetworkIO</a><br>"
	+ "<a href=\"/DeadLock\">DeadLock</a><br>" + "<a href=\"/Regex\">Regex</a><br>");
	}
	}


	@WebServlet(name = "Sleep", urlPatterns = { "/Sleep" })
	public static class Sleep extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	try {
	Thread.sleep(10000);
	} catch (InterruptedException e) {
	e.printStackTrace();
	}
	}
	}

	@WebServlet(name = "NetworkIO", urlPatterns = { "/NetworkIO" })
	public static class NetworkIO extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	URL url = new URL("http://localhost:8080/Sleep");
	InputStream is = url.openConnection().getInputStream();
	}
	}

	@WebServlet(name = "DeadLock", urlPatterns = { "/DeadLock" })
	public static class DeadLock extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	Object obj1 = new Object();
	Object obj2 = new Object();

	new Thread(() -> {
	synchronized (obj1) {
	sleep(500);
	synchronized (obj2) {
	}
	}
	}).start();

	new Thread(() -> {
	synchronized (obj2) {
	sleep(500);
	synchronized (obj1) {
	}
	}
	}).start();
	}

	private void sleep(long millis) {
	try {
	Thread.sleep(millis);
	} catch (Exception e) {
	e.printStackTrace();
	}
	}
	}

	@WebServlet(name = "Regex", urlPatterns = { "/Regex" })
	public static class Regex extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	for (int i = 0; i < 50000000; i++) {
	"hogehoge".replaceAll("hoge", "fuga");
	}
	resp.getWriter().println("Done!");
	}
	}
	}