Merge branch 'masterEugen' into tutorials/titleCase

cdi/pom.xml

@@ -14,6 +14,24 @@
     </parent>
 
     <dependencies>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-core</artifactId>
+            <version>1.3</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>3.10.0</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-context</artifactId>

cdi/src/main/java/com/baeldung/dependencyinjection/application/FileApplication.java

@@ -0,0 +1,18 @@
+package com.baeldung.dependencyinjection.application;
+
+import com.baeldung.dependencyinjection.imageprocessors.ImageFileProcessor;
+import org.jboss.weld.environment.se.Weld;
+import org.jboss.weld.environment.se.WeldContainer;
+
+public class FileApplication {
+    
+    public static void main(String[] args) {
+        Weld weld = new Weld();
+        WeldContainer container = weld.initialize();
+        ImageFileProcessor imageFileProcessor = container.select(ImageFileProcessor.class).get();
+        System.out.println(imageFileProcessor.openFile("file1.png"));
+        System.out.println(imageFileProcessor.writeFile("file1.png"));
+        System.out.println(imageFileProcessor.saveFile("file1.png"));
+        container.shutdown();
+    }
+}

cdi/src/main/java/com/baeldung/dependencyinjection/factories/TimeLoggerFactory.java

@@ -0,0 +1,14 @@
+package com.baeldung.dependencyinjection.factories;
+
+import com.baeldung.dependencyinjection.loggers.TimeLogger;
+import java.text.SimpleDateFormat;
+import java.util.Calendar;
+import javax.enterprise.inject.Produces;
+
+public class TimeLoggerFactory {
+    
+    @Produces
+    public TimeLogger getTimeLogger() {
+        return new TimeLogger(new SimpleDateFormat("HH:mm"), Calendar.getInstance());
+    }
+}

cdi/src/main/java/com/baeldung/dependencyinjection/imagefileeditors/GifFileEditor.java

@@ -0,0 +1,27 @@
+package com.baeldung.dependencyinjection.imagefileeditors;
+
+import com.baeldung.dependencyinjection.qualifiers.GifFileEditorQualifier;
+
+@GifFileEditorQualifier
+public class GifFileEditor implements ImageFileEditor {
+    
+    @Override
+    public String openFile(String fileName) {
+        return "Opening GIF file " + fileName;
+    }
+
+    @Override
+    public String editFile(String fileName) {
+        return "Editing GIF file " + fileName;
+    }
+    
+    @Override
+    public String writeFile(String fileName) {
+        return "Writing GIF file " + fileName;
+    }
+
+    @Override
+    public String saveFile(String fileName) {
+        return "Saving GIF file " + fileName;
+    }
+}

cdi/src/main/java/com/baeldung/dependencyinjection/imagefileeditors/ImageFileEditor.java

@@ -0,0 +1,12 @@
+package com.baeldung.dependencyinjection.imagefileeditors;
+
+public interface ImageFileEditor {
+    
+    String openFile(String fileName);
+    
+    String editFile(String fileName);
+    
+    String writeFile(String fileName);
+    
+    String saveFile(String fileName);
+}

cdi/src/main/java/com/baeldung/dependencyinjection/imagefileeditors/JpgFileEditor.java

@@ -0,0 +1,27 @@
+package com.baeldung.dependencyinjection.imagefileeditors;
+
+import com.baeldung.dependencyinjection.qualifiers.JpgFileEditorQualifier;
+
+@JpgFileEditorQualifier
+public class JpgFileEditor implements ImageFileEditor {
+   
+    @Override
+    public String openFile(String fileName) {
+        return "Opening JPG file " + fileName;
+    }
+
+    @Override
+    public String editFile(String fileName) {
+        return "Editing JPG file " + fileName;
+    }
+    
+    @Override
+    public String writeFile(String fileName) {
+        return "Writing JPG file " + fileName;
+    }
+
+    @Override
+    public String saveFile(String fileName) {
+        return "Saving JPG file " + fileName;
+    }
+}

cdi/src/main/java/com/baeldung/dependencyinjection/imagefileeditors/PngFileEditor.java

@@ -0,0 +1,27 @@
+package com.baeldung.dependencyinjection.imagefileeditors;
+
+import com.baeldung.dependencyinjection.qualifiers.PngFileEditorQualifier;
+
+@PngFileEditorQualifier
+public class PngFileEditor implements ImageFileEditor {
+   
+    @Override
+    public String openFile(String fileName) {
+        return "Opening PNG file " + fileName;
+    }
+
+    @Override
+    public String editFile(String fileName) {
+        return "Editing PNG file " + fileName;
+    }
+    
+    @Override
+    public String writeFile(String fileName) {
+        return "Writing PNG file " + fileName;
+    }
+
+    @Override
+    public String saveFile(String fileName) {
+        return "Saving PNG file " + fileName;
+    }
+}

cdi/src/main/java/com/baeldung/dependencyinjection/imageprocessors/ImageFileProcessor.java

@@ -0,0 +1,42 @@
+package com.baeldung.dependencyinjection.imageprocessors;
+
+import com.baeldung.dependencyinjection.loggers.TimeLogger;
+import com.baeldung.dependencyinjection.qualifiers.PngFileEditorQualifier;
+import javax.inject.Inject;
+import com.baeldung.dependencyinjection.imagefileeditors.ImageFileEditor;
+
+public class ImageFileProcessor {
+    
+    private final ImageFileEditor imageFileEditor;
+    private final TimeLogger timeLogger;
+    
+    @Inject
+    public ImageFileProcessor(@PngFileEditorQualifier ImageFileEditor imageFileEditor, TimeLogger timeLogger) {
+        this.imageFileEditor = imageFileEditor;
+        this.timeLogger = timeLogger;
+    }
+    
+    public ImageFileEditor getImageFileditor() {
+        return imageFileEditor;
+    }
+    
+    public TimeLogger getTimeLogger() {
+        return timeLogger;
+    }
+    
+    public String openFile(String fileName) {
+        return imageFileEditor.openFile(fileName) + " at: " + timeLogger.getTime();
+    }
+    
+    public String editFile(String fileName) {
+        return imageFileEditor.editFile(fileName) + " at: " + timeLogger.getTime();
+    }
+     
+    public String writeFile(String fileName) {
+        return imageFileEditor.writeFile(fileName) + " at: " + timeLogger.getTime();
+    }
+    
+    public String saveFile(String fileName) {
+        return imageFileEditor.saveFile(fileName)+ " at: " + timeLogger.getTime();
+    }
+}

cdi/src/main/java/com/baeldung/dependencyinjection/loggers/TimeLogger.java

@@ -0,0 +1,19 @@
+package com.baeldung.dependencyinjection.loggers;
+
+import java.text.SimpleDateFormat;
+import java.util.Calendar;
+
+public class TimeLogger {
+    
+    private final SimpleDateFormat dateFormat;
+    private final Calendar calendar;
+    
+    public TimeLogger(SimpleDateFormat dateFormat, Calendar calendar) {
+        this.dateFormat = dateFormat;
+        this.calendar = calendar;
+    }
+    
+    public String getTime() {
+        return dateFormat.format(calendar.getTime());
+    }
+}

cdi/src/main/java/com/baeldung/dependencyinjection/qualifiers/GifFileEditorQualifier.java

@@ -0,0 +1,12 @@
+package com.baeldung.dependencyinjection.qualifiers;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import javax.inject.Qualifier;
+
+@Qualifier
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.FIELD, ElementType.METHOD, ElementType.TYPE, ElementType.PARAMETER})
+public @interface GifFileEditorQualifier {}

cdi/src/main/java/com/baeldung/dependencyinjection/qualifiers/JpgFileEditorQualifier.java

@@ -0,0 +1,12 @@
+package com.baeldung.dependencyinjection.qualifiers;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import javax.inject.Qualifier;
+
+@Qualifier
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.FIELD, ElementType.METHOD, ElementType.TYPE, ElementType.PARAMETER})
+public @interface JpgFileEditorQualifier {}

cdi/src/main/java/com/baeldung/dependencyinjection/qualifiers/PngFileEditorQualifier.java

@@ -0,0 +1,12 @@
+package com.baeldung.dependencyinjection.qualifiers;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import javax.inject.Qualifier;
+
+@Qualifier
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.FIELD, ElementType.METHOD, ElementType.TYPE, ElementType.PARAMETER})
+public @interface PngFileEditorQualifier {}

cdi/src/test/java/com/baeldung/test/dependencyinjection/GifFileEditorUnitTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.test.dependencyinjection;
+
+import com.baeldung.dependencyinjection.imagefileeditors.GifFileEditor;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class GifFileEditorUnitTest {
+    
+    private static GifFileEditor gifFileEditor;
+    
+    
+    @BeforeClass
+    public static void setGifFileEditorInstance() {
+        gifFileEditor = new GifFileEditor();
+    }
+    
+    @Test
+    public void givenGifFileEditorlInstance_whenCalledopenFile_thenOneAssertion() {
+        assertThat(gifFileEditor.openFile("file1.gif")).isEqualTo("Opening GIF file file1.gif");
+    }
+    
+    @Test
+    public void givenGifFileEditorlInstance_whenCallededitFile_thenOneAssertion() {
+        assertThat(gifFileEditor.editFile("file1.gif")).isEqualTo("Editing GIF file file1.gif");
+    }
+    
+    @Test
+    public void givenGifFileEditorInstance_whenCalledwriteFile_thenOneAssertion() {
+        assertThat(gifFileEditor.writeFile("file1.gif")).isEqualTo("Writing GIF file file1.gif");
+    }
+    
+    @Test
+    public void givenGifFileEditorInstance_whenCalledsaveFile_thenOneAssertion() {
+        assertThat(gifFileEditor.saveFile("file1.gif")).isEqualTo("Saving GIF file file1.gif");
+    }
+}

cdi/src/test/java/com/baeldung/test/dependencyinjection/ImageProcessorUnitTest.java

@@ -0,0 +1,70 @@
+package com.baeldung.test.dependencyinjection;
+
+import com.baeldung.dependencyinjection.imagefileeditors.GifFileEditor;
+import com.baeldung.dependencyinjection.imagefileeditors.JpgFileEditor;
+import com.baeldung.dependencyinjection.imagefileeditors.PngFileEditor;
+import com.baeldung.dependencyinjection.imageprocessors.ImageFileProcessor;
+import com.baeldung.dependencyinjection.loggers.TimeLogger;
+import java.text.SimpleDateFormat;
+import java.util.Calendar;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.jboss.weld.environment.se.Weld;
+import org.jboss.weld.environment.se.WeldContainer;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class ImageProcessorUnitTest {
+    
+    private static ImageFileProcessor imageFileProcessor;
+    private static SimpleDateFormat dateFormat;
+    private static Calendar calendar;
+    
+    
+    @BeforeClass
+    public static void setImageProcessorInstance() {
+        Weld weld = new Weld();
+        WeldContainer container = weld.initialize();
+        imageFileProcessor = container.select(ImageFileProcessor.class).get();
+        container.shutdown();
+    }
+    
+    @BeforeClass
+    public static void setSimpleDateFormatInstance() {
+        dateFormat = new SimpleDateFormat("HH:mm");
+    }
+    
+    @BeforeClass
+    public static void setCalendarInstance() {
+        calendar = Calendar.getInstance();
+    }
+    
+    @Test
+    public void givenImageProcessorInstance_whenInjectedPngFileEditorandTimeLoggerInstances_thenTwoAssertions() {
+        assertThat(imageFileProcessor.getImageFileditor()).isInstanceOf(PngFileEditor.class);
+        assertThat(imageFileProcessor.getTimeLogger()).isInstanceOf(TimeLogger.class);
+    }
+    
+    @Test
+    public void givenImageProcessorInstance_whenCalledopenFile_thenOneAssertion() {
+        String currentTime = dateFormat.format(calendar.getTime());
+        assertThat(imageFileProcessor.openFile("file1.png")).isEqualTo("Opening PNG file file1.png at: " + currentTime);
+    }
+    
+    @Test
+    public void givenImageProcessorInstance_whenCallededitFile_thenOneAssertion() {
+        String currentTime = dateFormat.format(calendar.getTime());
+        assertThat(imageFileProcessor.editFile("file1.png")).isEqualTo("Editing PNG file file1.png at: " + currentTime);
+    }
+    
+    @Test
+    public void givenImageProcessorInstance_whenCalledwriteFile_thenOneAssertion() {
+        String currentTime = dateFormat.format(calendar.getTime());
+        assertThat(imageFileProcessor.writeFile("file1.png")).isEqualTo("Writing PNG file file1.png at: " + currentTime);
+    }
+    
+    @Test
+    public void givenImageProcessorInstance_whenCalledsaveFile_thenOneAssertion() {
+        String currentTime = dateFormat.format(calendar.getTime());
+        assertThat(imageFileProcessor.saveFile("file1.png")).isEqualTo("Saving PNG file file1.png at: " + currentTime);
+    }
+}

cdi/src/test/java/com/baeldung/test/dependencyinjection/JpgFileEditorUnitTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.test.dependencyinjection;
+
+import com.baeldung.dependencyinjection.imagefileeditors.JpgFileEditor;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class JpgFileEditorUnitTest {
+    
+    private static JpgFileEditor jpgFileUtil;
+    
+    
+    @BeforeClass
+    public static void setJpgFileEditorInstance() {
+        jpgFileUtil = new JpgFileEditor();
+    }
+    
+    @Test
+    public void givenJpgFileEditorInstance_whenCalledopenFile_thenOneAssertion() {
+        assertThat(jpgFileUtil.openFile("file1.jpg")).isEqualTo("Opening JPG file file1.jpg");
+    }
+    
+    @Test
+    public void givenJpgFileEditorlInstance_whenCallededitFile_thenOneAssertion() {
+        assertThat(jpgFileUtil.editFile("file1.gif")).isEqualTo("Editing JPG file file1.gif");
+    }
+    
+    @Test
+    public void givenJpgFileEditorInstance_whenCalledwriteFile_thenOneAssertion() {
+        assertThat(jpgFileUtil.writeFile("file1.jpg")).isEqualTo("Writing JPG file file1.jpg");
+    }
+    
+    @Test
+    public void givenJpgFileEditorInstance_whenCalledsaveFile_thenOneAssertion() {
+        assertThat(jpgFileUtil.saveFile("file1.jpg")).isEqualTo("Saving JPG file file1.jpg");
+    }
+}

cdi/src/test/java/com/baeldung/test/dependencyinjection/PngFileEditorUnitTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.test.dependencyinjection;
+
+import com.baeldung.dependencyinjection.imagefileeditors.PngFileEditor;
+import com.baeldung.dependencyinjection.qualifiers.PngFileEditorQualifier;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+@PngFileEditorQualifier
+public class PngFileEditorUnitTest {
+    
+    private static PngFileEditor pngFileEditor;
+    
+    
+    @BeforeClass
+    public static void setPngFileEditorInstance() {
+        pngFileEditor = new PngFileEditor();
+    }
+    
+    @Test
+    public void givenPngFileEditorInstance_whenCalledopenFile_thenOneAssertion() {
+        assertThat(pngFileEditor.openFile("file1.png")).isEqualTo("Opening PNG file file1.png");
+    }
+    
+    @Test
+    public void givenPngFileEditorInstance_whenCallededitFile_thenOneAssertion() {
+        assertThat(pngFileEditor.editFile("file1.png")).isEqualTo("Editing PNG file file1.png");
+    }
+    
+    @Test
+    public void givenPngFileEditorInstance_whenCalledwriteFile_thenOneAssertion() {
+        assertThat(pngFileEditor.writeFile("file1.png")).isEqualTo("Writing PNG file file1.png");
+    }
+    
+    @Test
+    public void givenPngFileEditorInstance_whenCalledsaveFile_thenOneAssertion() {
+        assertThat(pngFileEditor.saveFile("file1.png")).isEqualTo("Saving PNG file file1.png");
+    }
+}

cdi/src/test/java/com/baeldung/test/dependencyinjection/TimeLoggerFactoryUnitTest.java

@@ -0,0 +1,15 @@
+package com.baeldung.test.dependencyinjection;
+
+import com.baeldung.dependencyinjection.factories.TimeLoggerFactory;
+import com.baeldung.dependencyinjection.loggers.TimeLogger;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.Test;
+
+public class TimeLoggerFactoryUnitTest {
+    
+    @Test
+    public void givenTimeLoggerFactory_whenCalledgetTimeLogger_thenOneAssertion() {
+        TimeLoggerFactory timeLoggerFactory = new TimeLoggerFactory();
+        assertThat(timeLoggerFactory.getTimeLogger()).isInstanceOf(TimeLogger.class);
+    }
+}

cdi/src/test/java/com/baeldung/test/dependencyinjection/TimeLoggerUnitTest.java

@@ -0,0 +1,20 @@
+package com.baeldung.test.dependencyinjection;
+
+import com.baeldung.dependencyinjection.loggers.TimeLogger;
+import java.text.SimpleDateFormat;
+import java.util.Calendar;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.Test;
+
+public class TimeLoggerUnitTest {
+    
+    
+    @Test
+    public void givenTimeLoggerInstance_whenCalledgetLogTime_thenOneAssertion() {
+        SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm");
+        Calendar calendar = Calendar.getInstance();
+        TimeLogger timeLogger = new TimeLogger(dateFormat, calendar);
+        String currentTime = dateFormat.format(calendar.getTime());
+        assertThat(timeLogger.getTime()).isEqualTo(currentTime);
+    }
+}

javax-servlets/src/main/java/com/baeldung/servlets/ErrorHandlerServlet.java

@@ -0,0 +1,34 @@
+package com.baeldung.servlets;
+
+import javax.servlet.annotation.*;
+import javax.servlet.http.*;
+import java.io.*;
+import java.util.*;
+
+import static javax.servlet.RequestDispatcher.*;
+
+@WebServlet(urlPatterns = "/errorHandler")
+public class ErrorHandlerServlet extends HttpServlet {
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
+            throws IOException {
+        resp.setContentType("text/html; charset=utf-8");
+        try (PrintWriter writer = resp.getWriter()) {
+            writer.write("<html><head><title>Error description</title></head><body>");
+            writer.write("<h2>Error description</h2>");
+            writer.write("<ul>");
+            Arrays.asList(ERROR_STATUS_CODE, ERROR_EXCEPTION_TYPE, ERROR_MESSAGE)
+                    .forEach(e ->
+                            writer.write("<li>" + e + ":" + req.getAttribute(e) + " </li>")
+                    );
+            writer.write("</ul>");
+            writer.write("</html></body>");
+        }
+
+        Exception exception = (Exception) req.getAttribute(ERROR_EXCEPTION);
+        if (IllegalArgumentException.class.isInstance(exception)) {
+            getServletContext().log("Error on an application argument", exception);
+        }
+    }
+}

javax-servlets/src/main/java/com/baeldung/servlets/RandomErrorServlet.java

@@ -0,0 +1,13 @@
+package com.baeldung.servlets;
+
+import javax.servlet.annotation.*;
+import javax.servlet.http.*;
+
+@WebServlet(urlPatterns = "/randomError")
+public class RandomErrorServlet extends HttpServlet {
+
+    @Override
+    protected void doGet(HttpServletRequest req, final HttpServletResponse resp) {
+        throw new IllegalStateException("Random error");
+    }
+}

javax-servlets/src/main/webapp/WEB-INF/web.xml

@@ -0,0 +1,16 @@
+<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xmlns="http://java.sun.com/xml/ns/javaee"
+         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
+    http://java.sun.com/xml/ns/javaee/web-app_3_1.xsd"
+         version="3.1">
+
+    <error-page>
+        <error-code>404</error-code>
+        <location>/error-404.html</location> <!-- /src/main/webapp/error-404.html-->
+    </error-page>
+
+    <error-page>
+        <exception-type>java.lang.Exception</exception-type>
+        <location>/errorHandler</location>
+    </error-page>
+</web-app>

javax-servlets/src/main/webapp/error-404.html

@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <title>Error page</title>
+</head>
+<body>
+
+<h2>Error: Page not found</h2>
+
+<a href="./">Go back home</a>
+
+</body>
+</html>

kotlin-ktor/.gitignore

@@ -0,0 +1,14 @@
+/bin/
+
+#ignore gradle
+.gradle/
+
+
+#ignore build and generated files
+build/
+node/
+out/
+
+#ignore installed node modules and package lock file
+node_modules/
+package-lock.json

kotlin-ktor/build.gradle

@@ -0,0 +1,47 @@
+
+
+group 'com.baeldung.ktor'
+version '1.0-SNAPSHOT'
+
+
+buildscript {
+    ext.kotlin_version = '1.2.40'
+    ext.ktor_version = '0.9.2'
+
+    repositories {
+        mavenCentral()
+    }
+    dependencies {
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+    }
+}
+
+apply plugin: 'java'
+apply plugin: 'kotlin'
+apply plugin: 'application'
+
+mainClassName = 'APIServer.kt'
+
+sourceCompatibility = 1.8
+compileKotlin { kotlinOptions.jvmTarget = "1.8" }
+compileTestKotlin { kotlinOptions.jvmTarget = "1.8" }
+
+kotlin { experimental { coroutines "enable" } }
+
+repositories {
+    mavenCentral()
+    jcenter()
+    maven { url "https://dl.bintray.com/kotlin/ktor" }
+}
+
+dependencies {
+    compile "io.ktor:ktor-server-netty:$ktor_version"
+    compile "ch.qos.logback:logback-classic:1.2.1"
+    compile "io.ktor:ktor-gson:$ktor_version"
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+
+}
+task runServer(type: JavaExec) {
+    main = 'APIServer'
+    classpath = sourceSets.main.runtimeClasspath
+}

kotlin-ktor/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-bin.zip

kotlin-ktor/gradlew

@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"

kotlin-ktor/gradlew.bat

@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

kotlin-ktor/resources/logback.xml

@@ -0,0 +1,11 @@
+<configuration>
+  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+    <encoder>
+      <pattern>%d{YYYY-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+    </encoder>
+  </appender>
+
+  <root level="INFO">
+    <appender-ref ref="STDOUT"/>
+  </root>
+</configuration>

kotlin-ktor/settings.gradle

@@ -0,0 +1,2 @@
+rootProject.name = 'KtorWithKotlin'
+

kotlin-ktor/src/main/kotlin/APIServer.kt

@@ -0,0 +1,57 @@
+@file:JvmName("APIServer")
+
+
+
+import io.ktor.application.call
+import io.ktor.application.install
+import io.ktor.features.CallLogging
+import io.ktor.features.ContentNegotiation
+import io.ktor.features.DefaultHeaders
+import io.ktor.gson.gson
+import io.ktor.http.ContentType
+import io.ktor.request.path
+import io.ktor.response.respond
+import io.ktor.response.respondText
+import io.ktor.routing.get
+import io.ktor.routing.routing
+import io.ktor.server.engine.embeddedServer
+import io.ktor.server.netty.Netty
+import org.slf4j.event.Level
+
+data class Author(val name: String, val website: String)
+fun main(args: Array<String>) {
+
+    val jsonResponse = """{
+            "id": 1,
+            "task": "Pay waterbill",
+            "description": "Pay water bill today",
+        }"""
+
+
+    embeddedServer(Netty, 8080) {
+        install(DefaultHeaders) {
+            header("X-Developer", "Baeldung")
+        }
+        install(CallLogging) {
+            level = Level.INFO
+            filter { call -> call.request.path().startsWith("/todo") }
+            filter { call -> call.request.path().startsWith("/author") }
+        }
+        install(ContentNegotiation) {
+            gson {
+                setPrettyPrinting()
+            }
+        }
+        routing {
+            get("/todo") {
+                call.respondText(jsonResponse, ContentType.Application.Json)
+            }
+            get("/author") {
+                val author = Author("baeldung", "baeldung.com")
+                call.respond(author)
+
+            }
+
+        }
+    }.start(wait = true)
+}

kotlin-ktor/webapp/WEB-INF/web.xml

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="ISO-8859-1" ?>
+
+<web-app xmlns="http://java.sun.com/xml/ns/javaee"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
+  version="3.0">
+  <!-- path to application.conf file, required -->
+  <!-- note that this file is always loaded as an absolute path from the classpath -->
+  <context-param>
+    <param-name>io.ktor.ktor.config</param-name>
+    <param-value>application.conf</param-value>
+  </context-param>
+
+  <servlet>
+    <display-name>KtorServlet</display-name>
+    <servlet-name>KtorServlet</servlet-name>
+    <servlet-class>io.ktor.server.servlet.ServletApplicationEngine</servlet-class>
+
+    <!-- required! -->
+    <async-supported>true</async-supported>
+
+    <!-- 100mb max file upload, optional -->
+    <multipart-config>
+      <max-file-size>304857600</max-file-size>
+      <max-request-size>304857600</max-request-size>
+      <file-size-threshold>0</file-size-threshold>
+    </multipart-config>
+  </servlet>
+
+  <servlet-mapping>
+    <servlet-name>KtorServlet</servlet-name>
+    <url-pattern>/</url-pattern>
+  </servlet-mapping>
+
+</web-app>

libraries/.gitignore

@@ -0,0 +1,8 @@
+*.class
+
+# Folders #
+/gensrc
+/target
+
+# Packaged files #
+*.jar

libraries/pom.xml

@@ -722,6 +722,17 @@
             <scope>test</scope>
         </dependency>
 
+        <dependency>
+            <groupId>com.squareup</groupId>
+            <artifactId>javapoet</artifactId>
+            <version>${javapoet.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-all</artifactId>
+            <version>${hamcrest-all.version}</version>
+            <scope>test</scope>
+        </dependency>
 
     </dependencies>
 
@@ -939,6 +950,8 @@
         <xchart-version>3.5.2</xchart-version>
         <commons-net.version>3.6</commons-net.version>
         <mockftpserver.version>2.7.1</mockftpserver.version>
+        <javapoet.version>1.10.0</javapoet.version>
+        <hamcrest-all.version>1.3</hamcrest-all.version>
     </properties>
 
 </project>

libraries/src/main/java/com/baeldung/javapoet/PersonGenerator.java

@@ -0,0 +1,183 @@
+package com.baeldung.javapoet;
+
+import com.squareup.javapoet.ClassName;
+import com.squareup.javapoet.CodeBlock;
+import com.squareup.javapoet.FieldSpec;
+import com.squareup.javapoet.JavaFile;
+import com.squareup.javapoet.MethodSpec;
+import com.squareup.javapoet.ParameterSpec;
+import com.squareup.javapoet.ParameterizedTypeName;
+import com.squareup.javapoet.TypeName;
+import com.squareup.javapoet.TypeSpec;
+
+import javax.lang.model.element.Modifier;
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.IntStream;
+
+public class PersonGenerator {
+
+    private static final String FOUR_WHITESPACES = "    ";
+    private static final String PERSON_PACKAGE_NAME = "com.baeldung.javapoet.test.person";
+
+    private File outputFile;
+
+    public PersonGenerator() {
+        outputFile = new File(getOutputPath().toUri());
+    }
+
+    public static String getPersonPackageName() {
+        return PERSON_PACKAGE_NAME;
+    }
+
+    public Path getOutputPath() {
+        return Paths.get(new File(".").getAbsolutePath() + "/gensrc");
+    }
+
+    public FieldSpec getDefaultNameField() {
+        return FieldSpec
+          .builder(String.class, "DEFAULT_NAME")
+          .addModifiers(Modifier.PUBLIC, Modifier.STATIC, Modifier.FINAL)
+          .initializer("$S", "Alice")
+          .build();
+    }
+
+    public MethodSpec getSortByLengthMethod() {
+        return MethodSpec
+          .methodBuilder("sortByLength")
+          .addModifiers(Modifier.PUBLIC, Modifier.STATIC)
+          .addParameter(ParameterSpec
+            .builder(ParameterizedTypeName.get(ClassName.get(List.class), TypeName.get(String.class)), "strings")
+            .build())
+          .addStatement("$T.sort($N, $L)", Collections.class, "strings", getComparatorAnonymousClass())
+          .build();
+    }
+
+    public MethodSpec getPrintNameMultipleTimesMethod() {
+        return MethodSpec
+          .methodBuilder("printNameMultipleTimes")
+          .addModifiers(Modifier.PUBLIC)
+          .addCode(getPrintNameMultipleTimesLambdaImpl())
+          .build();
+    }
+
+    public CodeBlock getPrintNameMultipleTimesImpl() {
+        return CodeBlock
+          .builder()
+          .beginControlFlow("for (int i = $L; i < $L; i++)")
+          .addStatement("System.out.println(name)")
+          .endControlFlow()
+          .build();
+    }
+
+    public CodeBlock getPrintNameMultipleTimesLambdaImpl() {
+        return CodeBlock
+          .builder()
+          .addStatement("$T<$T> names = new $T<>()", List.class, String.class, ArrayList.class)
+          .addStatement("$T.range($L, $L).forEach(i -> names.add(name))", IntStream.class, 0, 10)
+          .addStatement("names.forEach(System.out::println)")
+          .build();
+    }
+
+    public TypeSpec getGenderEnum() {
+        return TypeSpec
+          .enumBuilder("Gender")
+          .addModifiers(Modifier.PUBLIC)
+          .addEnumConstant("MALE")
+          .addEnumConstant("FEMALE")
+          .addEnumConstant("UNSPECIFIED")
+          .build();
+    }
+
+    public TypeSpec getPersonInterface() {
+        return TypeSpec
+          .interfaceBuilder("Person")
+          .addModifiers(Modifier.PUBLIC)
+          .addField(getDefaultNameField())
+          .addMethod(MethodSpec
+            .methodBuilder("getName")
+            .addModifiers(Modifier.PUBLIC, Modifier.ABSTRACT)
+            .returns(String.class)
+            .build())
+          .addMethod(MethodSpec
+            .methodBuilder("getDefaultName")
+            .addModifiers(Modifier.PUBLIC, Modifier.DEFAULT)
+            .returns(String.class)
+            .addCode(CodeBlock
+              .builder()
+              .addStatement("return DEFAULT_NAME")
+              .build())
+            .build())
+          .build();
+    }
+
+    public TypeSpec getStudentClass() {
+        return TypeSpec
+          .classBuilder("Student")
+          .addSuperinterface(ClassName.get(PERSON_PACKAGE_NAME, "Person"))
+          .addModifiers(Modifier.PUBLIC)
+          .addField(FieldSpec
+            .builder(String.class, "name")
+            .addModifiers(Modifier.PRIVATE)
+            .build())
+          .addMethod(MethodSpec
+            .methodBuilder("getName")
+            .addAnnotation(Override.class)
+            .addModifiers(Modifier.PUBLIC)
+            .returns(String.class)
+            .addStatement("return this.name")
+            .build())
+          .addMethod(MethodSpec
+            .methodBuilder("setName")
+            .addParameter(String.class, "name")
+            .addModifiers(Modifier.PUBLIC)
+            .addStatement("this.name = name")
+            .build())
+          .addMethod(getPrintNameMultipleTimesMethod())
+          .addMethod(getSortByLengthMethod())
+          .build();
+    }
+
+    public TypeSpec getComparatorAnonymousClass() {
+        return TypeSpec
+          .anonymousClassBuilder("")
+          .addSuperinterface(ParameterizedTypeName.get(Comparator.class, String.class))
+          .addMethod(MethodSpec
+            .methodBuilder("compare")
+            .addModifiers(Modifier.PUBLIC)
+            .addAnnotation(Override.class)
+            .addParameter(String.class, "a")
+            .addParameter(String.class, "b")
+            .returns(int.class)
+            .addStatement("return a.length() - b.length()")
+            .build())
+          .build();
+    }
+
+    public void generateGenderEnum() throws IOException {
+        writeToOutputFile(getPersonPackageName(), getGenderEnum());
+    }
+
+    public void generatePersonInterface() throws IOException {
+        writeToOutputFile(getPersonPackageName(), getPersonInterface());
+    }
+
+    public void generateStudentClass() throws IOException {
+        writeToOutputFile(getPersonPackageName(), getStudentClass());
+    }
+
+    private void writeToOutputFile(String packageName, TypeSpec typeSpec) throws IOException {
+        JavaFile javaFile = JavaFile
+          .builder(packageName, typeSpec)
+          .indent(FOUR_WHITESPACES)
+          .build();
+        javaFile.writeTo(outputFile);
+    }
+
+}

libraries/src/test/java/com/baeldung/javapoet/test/PersonGeneratorUnitTest.java

@@ -0,0 +1,99 @@
+package com.baeldung.javapoet.test;
+
+import com.baeldung.javapoet.PersonGenerator;
+import org.apache.commons.io.FileUtils;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
+@RunWith(JUnit4.class)
+public class PersonGeneratorUnitTest {
+
+    private PersonGenerator generator;
+    private Path generatedFolderPath;
+    private Path expectedFolderPath;
+
+    @Before
+    public void setUp() {
+        String packagePath = this
+          .getClass()
+          .getPackage()
+          .getName()
+          .replace(".", "/") + "/person";
+        generator = new PersonGenerator();
+        generatedFolderPath = generator
+          .getOutputPath()
+          .resolve(packagePath);
+        expectedFolderPath = Paths.get(new File(".").getAbsolutePath() + "/src/test/java/" + packagePath);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        FileUtils.deleteDirectory(new File(generator
+          .getOutputPath()
+          .toUri()));
+    }
+
+    @Test
+    public void whenGenerateGenderEnum_thenGenerateGenderEnumAndWriteToFile() throws IOException {
+        generator.generateGenderEnum();
+        String fileName = "Gender.java";
+        assertThatFileIsGeneratedAsExpected(fileName);
+        deleteGeneratedFile(fileName);
+    }
+
+    @Test
+    public void whenGeneratePersonInterface_thenGeneratePersonInterfaceAndWriteToFile() throws IOException {
+        generator.generatePersonInterface();
+        String fileName = "Person.java";
+        assertThatFileIsGeneratedAsExpected(fileName);
+        deleteGeneratedFile(fileName);
+    }
+
+    @Test
+    public void whenGenerateStudentClass_thenGenerateStudentClassAndWriteToFile() throws IOException {
+        generator.generateStudentClass();
+        String fileName = "Student.java";
+        assertThatFileIsGeneratedAsExpected(fileName);
+        deleteGeneratedFile(fileName);
+    }
+
+    private void assertThatFileIsGeneratedAsExpected(String fileName) throws IOException {
+        String generatedFileContent = extractFileContent(generatedFolderPath.resolve(fileName));
+        String expectedFileContent = extractFileContent(expectedFolderPath.resolve(fileName));
+
+        assertThat("Generated file is identical to the file with the expected content", generatedFileContent, is(equalTo(expectedFileContent)));
+
+    }
+
+    private void deleteGeneratedFile(String fileName) throws IOException {
+        Path generatedFilePath = generatedFolderPath.resolve(fileName);
+        Files.delete(generatedFilePath);
+    }
+
+    private String extractFileContent(Path filePath) throws IOException {
+        byte[] fileContentAsBytes = Files.readAllBytes(filePath);
+        String fileContentAsString = new String(fileContentAsBytes, StandardCharsets.UTF_8);
+
+        if (!fileContentAsString.contains("\r\n")) {
+            // file is not in DOS format
+            // convert it first, so that the content comparison will be relevant
+            return fileContentAsString.replaceAll("\n", "\r\n");
+        }
+        return fileContentAsString;
+    }
+
+}

libraries/src/test/java/com/baeldung/javapoet/test/person/Gender.java

@@ -0,0 +1,9 @@
+package com.baeldung.javapoet.test.person;
+
+public enum Gender {
+    MALE,
+
+    FEMALE,
+
+    UNSPECIFIED
+}

libraries/src/test/java/com/baeldung/javapoet/test/person/Person.java

@@ -0,0 +1,13 @@
+package com.baeldung.javapoet.test.person;
+
+import java.lang.String;
+
+public interface Person {
+    String DEFAULT_NAME = "Alice";
+
+    String getName();
+
+    default String getDefaultName() {
+        return DEFAULT_NAME;
+    }
+}

libraries/src/test/java/com/baeldung/javapoet/test/person/Student.java

@@ -0,0 +1,37 @@
+package com.baeldung.javapoet.test.person;
+
+import java.lang.Override;
+import java.lang.String;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.IntStream;
+
+public class Student implements Person {
+    private String name;
+
+    @Override
+    public String getName() {
+        return this.name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public void printNameMultipleTimes() {
+        List<String> names = new ArrayList<>();
+        IntStream.range(0, 10).forEach(i -> names.add(name));
+        names.forEach(System.out::println);
+    }
+
+    public static void sortByLength(List<String> strings) {
+        Collections.sort(strings, new Comparator<String>() {
+            @Override
+            public int compare(String a, String b) {
+                return a.length() - b.length();
+            }
+        });
+    }
+}

pom.xml

@@ -248,6 +248,7 @@
         <module>persistence-modules/liquibase</module>
         <module>spring-boot-property-exp</module>
         <module>testing-modules/mockserver</module>
+        <module>testing-modules/test-containers</module>
         <module>undertow</module>
         <module>vertx-and-rxjava</module>
         <module>saas</module>

testing-modules/test-containers/README.md

@@ -0,0 +1,2 @@
+### Relevant Articles:
+- [Docker Test Containers in Java Tests](TODO link to be added.)

testing-modules/test-containers/pom.xml

@@ -0,0 +1,119 @@
+<?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>
+
+	<!-- NOT NEEDED - JSP <groupId>com.baeldung</groupId> -->
+	<artifactId>test-containers</artifactId>
+	<version>1.0-SNAPSHOT</version>
+
+	<name>test-containers</name>
+	<description>Intro to Java Test Containers</description>
+
+	<parent>
+		<groupId>com.baeldung</groupId>
+		<artifactId>parent-modules</artifactId>
+		<version>1.0.0-SNAPSHOT</version>
+		<relativePath>../../</relativePath>
+	</parent>
+
+
+	<build>
+		<resources>
+			<resource>
+				<directory>src/test/resources</directory>
+				<filtering>true</filtering>
+			</resource>
+		</resources>
+		<plugins>
+			<plugin>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<version>${maven-surefire-plugin.version}</version>
+				<dependencies>
+					<dependency>
+						<groupId>org.junit.platform</groupId>
+						<artifactId>junit-platform-surefire-provider</artifactId>
+						<version>${junit.platform.version}</version>
+					</dependency>
+				</dependencies>
+			</plugin>
+			<plugin>
+				<groupId>org.codehaus.mojo</groupId>
+				<artifactId>exec-maven-plugin</artifactId>
+				<version>1.6.0</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>java</goal>
+						</goals>
+					</execution>
+				</executions>
+				<configuration>
+					<mainClass>com.baeldung.TestLauncher</mainClass>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.junit.platform</groupId>
+			<artifactId>junit-platform-runner</artifactId>
+			<version>${junit.platform.version}</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.junit.vintage</groupId>
+			<artifactId>junit-vintage-engine</artifactId>
+			<version>${junit.vintage.version}</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.apache.logging.log4j</groupId>
+			<artifactId>log4j-core</artifactId>
+			<version>${log4j2.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.testcontainers</groupId>
+			<artifactId>testcontainers</artifactId>
+			<version>1.7.2</version>
+		</dependency>
+		<dependency>
+			<groupId>org.testcontainers</groupId>
+			<artifactId>postgresql </artifactId>
+			<version>1.7.2</version>
+		</dependency>
+		<dependency>
+			<groupId>org.testcontainers</groupId>
+			<artifactId>selenium </artifactId>
+			<version>1.7.2</version>
+		</dependency>
+		<dependency>
+			<groupId>org.postgresql</groupId>
+			<artifactId>postgresql</artifactId>
+			<version>42.2.2</version>
+		</dependency>
+		<dependency>
+			<groupId>org.seleniumhq.selenium</groupId>
+			<artifactId>selenium-remote-driver</artifactId>
+			<version>3.12.0</version>
+		</dependency>
+
+	</dependencies>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<java.version>1.8</java.version>
+		<junit.jupiter.version>5.1.0</junit.jupiter.version>
+		<junit.platform.version>1.0.1</junit.platform.version>
+		<junit.vintage.version>4.12.1</junit.vintage.version>
+		<log4j2.version>2.8.2</log4j2.version>
+		<h2.version>1.4.196</h2.version>
+		<mockito.version>2.11.0</mockito.version>
+
+		<maven-compiler-plugin.version>3.7.0</maven-compiler-plugin.version>
+		<maven-surefire-plugin.version>2.19.1</maven-surefire-plugin.version>
+		<spring.version>5.0.1.RELEASE</spring.version>
+	</properties>
+
+</project>

testing-modules/test-containers/src/test/java/com/baeldung/testconainers/DockerComposeContainerUnitTest.java

@@ -0,0 +1,47 @@
+package com.baeldung.testconainers;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.testcontainers.containers.DockerComposeContainer;
+
+public class DockerComposeContainerUnitTest {
+    @ClassRule
+    public static DockerComposeContainer compose = 
+      new DockerComposeContainer(
+        new File("src/test/resources/test-compose.yml"))
+          .withExposedService("simpleWebServer_1", 80);
+
+    @Test
+    public void givenSimpleWebServerContainer_whenGetReuqest_thenReturnsResponse()
+      throws Exception {
+        String address = "http://" + compose.getServiceHost("simpleWebServer_1", 80)
+          + ":" + compose.getServicePort("simpleWebServer_1", 80);
+        String response = simpleGetRequest(address);
+        
+        assertEquals(response, "Hello World!");
+    }
+
+    private String simpleGetRequest(String address) throws Exception {
+        URL url = new URL(address);
+        HttpURLConnection con = (HttpURLConnection) url.openConnection();
+        con.setRequestMethod("GET");
+
+        BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
+        String inputLine;
+        StringBuffer content = new StringBuffer();
+        while ((inputLine = in.readLine()) != null) {
+            content.append(inputLine);
+        }
+        in.close();
+
+        return content.toString();
+    }
+}

testing-modules/test-containers/src/test/java/com/baeldung/testconainers/GenericContainerUnitTest.java

@@ -0,0 +1,51 @@
+package com.baeldung.testconainers;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.junit.platform.commons.annotation.Testable;
+import org.testcontainers.containers.GenericContainer;
+
+@Testable
+public class GenericContainerUnitTest {
+    @ClassRule
+    public static GenericContainer simpleWebServer =
+      new GenericContainer("alpine:3.2")
+        .withExposedPorts(80)
+        .withCommand("/bin/sh", "-c", "while true; do echo "
+          + "\"HTTP/1.1 200 OK\n\nHello World!\" | nc -l -p 80; done");
+
+    @Test
+    public void givenSimpleWebServerContainer_whenGetReuqest_thenReturnsResponse()
+      throws Exception {
+        String address = "http://" 
+          + simpleWebServer.getContainerIpAddress() 
+          + ":" + simpleWebServer.getMappedPort(80);
+        String response = simpleGetRequest(address);
+        
+        assertEquals(response, "Hello World!");
+    }
+
+    private String simpleGetRequest(String address) throws Exception {
+        URL url = new URL(address);
+        HttpURLConnection con = (HttpURLConnection) url.openConnection();
+        con.setRequestMethod("GET");
+
+        BufferedReader in = new BufferedReader(
+          new InputStreamReader(con.getInputStream()));
+        String inputLine;
+        StringBuffer content = new StringBuffer();
+        while ((inputLine = in.readLine()) != null) {
+            content.append(inputLine);
+        }
+        in.close();
+
+        return content.toString();
+    }
+}

testing-modules/test-containers/src/test/java/com/baeldung/testconainers/PostgreSqlContainerUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.testconainers;
+
+import static org.junit.Assert.assertEquals;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.platform.commons.annotation.Testable;
+import org.testcontainers.containers.PostgreSQLContainer;
+
+@Testable
+public class PostgreSqlContainerUnitTest {
+    @Rule
+    public PostgreSQLContainer postgresContainer = new PostgreSQLContainer();
+
+    @Test
+    public void whenSelectQueryExecuted_thenResulstsReturned() throws Exception {
+        ResultSet resultSet = performQuery(postgresContainer, "SELECT 1");
+        resultSet.next();
+        int result = resultSet.getInt(1);
+        assertEquals(1, result);
+    }
+
+    private ResultSet performQuery(PostgreSQLContainer postgres, String query) throws SQLException {
+        String jdbcUrl = postgres.getJdbcUrl();
+        String username = postgres.getUsername();
+        String password = postgres.getPassword();
+        Connection conn = DriverManager.getConnection(jdbcUrl, username, password);
+        return conn.createStatement()
+            .executeQuery(query);
+    }
+}

testing-modules/test-containers/src/test/java/com/baeldung/testconainers/WebDriverContainerUnitTest.java

@@ -0,0 +1,30 @@
+package com.baeldung.testconainers;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.ClassRule;
+import org.junit.Rule;
+import org.junit.Test;
+import org.openqa.selenium.By;
+import org.openqa.selenium.remote.DesiredCapabilities;
+import org.openqa.selenium.remote.RemoteWebDriver;
+import org.testcontainers.DockerClientFactory;
+import org.testcontainers.containers.BrowserWebDriverContainer;
+import org.testcontainers.containers.GenericContainer;
+
+public class WebDriverContainerUnitTest {
+    @Rule
+    public BrowserWebDriverContainer chrome
+      = new BrowserWebDriverContainer()
+        .withDesiredCapabilities(DesiredCapabilities.chrome());
+
+    @Test
+    public void whenNavigatedToPage_thenHeadingIsInThePage() {
+        RemoteWebDriver driver = chrome.getWebDriver();
+        driver.get("https://saucelabs.com/test/guinea-pig");
+        String heading = driver.findElement(By.xpath("/html/body/h1"))
+            .getText();
+        assertEquals("This page is a Selenium sandbox", heading);
+    }
+    
+}

testing-modules/test-containers/src/test/resources/test-compose.yml

@@ -0,0 +1,3 @@
+simpleWebServer:
+  image: alpine:3.2
+  command: ["/bin/sh", "-c", "while true; do echo 'HTTP/1.1 200 OK\n\nHello World!' | nc -l -p 80; done"]