init project

.gitignore

+# Created by .ignore support plugin (hsz.mobi)
+### JetBrains template
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and WebStorm
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+### Java template
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+!/.idea/
+!/leetcode.iml
+/.gitignore
+/leetcode.iml
+/.idea/

leetcode1114/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>leetcode-parent</artifactId>
+        <groupId>com.duanledexianxianxian.leetcode</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>leetcode1114</artifactId>
+
+    <name>leetcode1114</name>
+    <!-- FIXME change it to the project's website -->
+    <url>http://www.example.com</url>
+</project>

leetcode1114/src/main/java/com/duanledexianxianxian/leetcode/Foo.java

+package com.duanledexianxianxian.leetcode;
+
+import java.util.concurrent.CountDownLatch;
+
+/**
+ * Hello world!
+ *
+ * @author Administrator
+ */
+class Foo {
+    CountDownLatch stage1 = new CountDownLatch(1);
+    CountDownLatch stage2 = new CountDownLatch(1);
+
+    public Foo() {
+
+    }
+
+    public void first(Runnable printFirst) throws InterruptedException {
+
+        // printFirst.run() outputs "first". Do not change or remove this line.
+        printFirst.run();
+        stage1.countDown();
+    }
+
+    public void second(Runnable printSecond) throws InterruptedException {
+
+        // printSecond.run() outputs "second". Do not change or remove this line.
+        stage1.await();
+        printSecond.run();
+        stage2.countDown();
+    }
+
+    public void third(Runnable printThird) throws InterruptedException {
+
+        // printThird.run() outputs "third". Do not change or remove this line.
+        stage2.await();
+        printThird.run();
+    }
+
+    public static void main(String[] args) {
+        Foo foo=new Foo();
+//        创建3个线程
+
+        Thread thread1 = new Thread(() -> {
+            try {
+                foo.first(()->{
+                    System.out.println("1");
+                });
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        });
+
+        Thread thread2 = new Thread(() -> {
+            try {
+                foo.second(()->{
+                    System.out.println("2");
+                });
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        });
+
+        Thread thread3 = new Thread(() -> {
+            try {
+                foo.third(()->{
+                    System.out.println("3");
+                });
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        });
+
+        thread1.start();
+        thread2.start();
+        thread3.start();
+
+    }
+}

leetcode1114/src/test/java/com/duanledexianxianxian/leetcode/AppTest.java

+package com.duanledexianxianxian.leetcode;
+
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+/**
+ * Unit test for simple Foo.
+ */
+public class AppTest 
+{
+    /**
+     * Rigorous Test :-)
+     */
+    @Test
+    public void shouldAnswerWithTrue()
+    {
+        assertTrue( true );
+    }
+}

pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>com.duanledexianxianxian.leetcode</groupId>
+  <artifactId>leetcode-parent</artifactId>
+  <packaging>pom</packaging>
+  <version>1.0-SNAPSHOT</version>
+  <modules>
+    <module>leetcode1114</module>
+  </modules>
+
+  <name>leetcode-parent</name>
+  <!-- FIXME change it to the project's website -->
+  <url>http://www.example.com</url>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.11</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
+      <plugins>
+        <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
+        <plugin>
+          <artifactId>maven-clean-plugin</artifactId>
+          <version>3.1.0</version>
+        </plugin>
+        <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
+        <plugin>
+          <artifactId>maven-resources-plugin</artifactId>
+          <version>3.0.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-compiler-plugin</artifactId>
+          <version>3.8.0</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-surefire-plugin</artifactId>
+          <version>2.22.1</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-jar-plugin</artifactId>
+          <version>3.0.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-install-plugin</artifactId>
+          <version>2.5.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-deploy-plugin</artifactId>
+          <version>2.8.2</version>
+        </plugin>
+        <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
+        <plugin>
+          <artifactId>maven-site-plugin</artifactId>
+          <version>3.7.1</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-project-info-reports-plugin</artifactId>
+          <version>3.0.0</version>
+        </plugin>
+      </plugins>
+    </pluginManagement>
+  </build>
+</project>

src/main/java/com/duanledexianxianxian/leetcode/App.java

+package com.duanledexianxianxian.leetcode;
+
+/**
+ * Hello world!
+ *
+ */
+public class App 
+{
+    public static void main( String[] args )
+    {
+        System.out.println( "Hello World!" );
+    }
+}

src/test/java/com/duanledexianxianxian/leetcode/AppTest.java

+package com.duanledexianxianxian.leetcode;
+
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+/**
+ * Unit test for simple App.
+ */
+public class AppTest 
+{
+    /**
+     * Rigorous Test :-)
+     */
+    @Test
+    public void shouldAnswerWithTrue()
+    {
+        assertTrue( true );
+    }
+}