BAEL-1174: A Quick Guide to Spring Cloud Consul

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2017 Eugen Paraschiv
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

algorithms/README.md

@@ -14,3 +14,4 @@
 - [Bubble Sort in Java](http://www.baeldung.com/java-bubble-sort)
 - [Introduction to JGraphT](http://www.baeldung.com/jgrapht)
 - [Introduction to Minimax Algorithm](http://www.baeldung.com/java-minimax-algorithm)
+- [How to Calculate Levenshtein Distance in Java?](http://www.baeldung.com/java-levenshtein-distance)

algorithms/src/main/java/com/baeldung/algorithms/prime/PrimeGenerator.java

@@ -0,0 +1,59 @@
+package com.baeldung.algorithms.prime;
+
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class PrimeGenerator {
+    public static List<Integer> sieveOfEratosthenes(int n) {
+        final boolean prime[] = new boolean[n + 1];
+        Arrays.fill(prime, true);
+
+        for (int p = 2; p * p <= n; p++) {
+            if (prime[p]) {
+                for (int i = p * 2; i <= n; i += p)
+                    prime[i] = false;
+            }
+        }
+
+        final List<Integer> primes = new LinkedList<>();
+        for (int i = 2; i <= n; i++) {
+            if (prime[i])
+                primes.add(i);
+        }
+        return primes;
+    }
+
+    public static List<Integer> primeNumbersBruteForce(int max) {
+        final List<Integer> primeNumbers = new LinkedList<Integer>();
+        for (int i = 2; i <= max; i++) {
+            if (isPrimeBruteForce(i)) {
+                primeNumbers.add(i);
+            }
+        }
+        return primeNumbers;
+    }
+
+    private static boolean isPrimeBruteForce(int x) {
+        for (int i = 2; i < x; i++) {
+            if (x % i == 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public static List<Integer> primeNumbersTill(int max) {
+        return IntStream.rangeClosed(2, max)
+            .filter(x -> isPrime(x))
+            .boxed()
+            .collect(Collectors.toList());
+    }
+
+    private static boolean isPrime(int x) {
+        return IntStream.rangeClosed(2, (int) (Math.sqrt(x)))
+            .allMatch(n -> x % n != 0);
+    }
+}

algorithms/src/test/java/com/baeldung/algorithms/prime/PrimeGeneratorTest.java

@@ -0,0 +1,28 @@
+package com.baeldung.algorithms.prime;
+
+import static com.baeldung.algorithms.prime.PrimeGenerator.*;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class PrimeGeneratorTest {
+    @Test
+    public void whenBruteForced_returnsSuccessfully() {
+        final List<Integer> primeNumbers = primeNumbersBruteForce(20);
+        assertEquals(Arrays.asList(new Integer[] { 2, 3, 5, 7, 11, 13, 17, 19 }), primeNumbers);
+    }
+
+    @Test
+    public void whenOptimized_returnsSuccessfully() {
+        final List<Integer> primeNumbers = primeNumbersTill(20);
+        assertEquals(Arrays.asList(new Integer[] { 2, 3, 5, 7, 11, 13, 17, 19 }), primeNumbers);
+    }
+
+    @Test
+    public void whenSieveOfEratosthenes_returnsSuccessfully() {
+        final List<Integer> primeNumbers = sieveOfEratosthenes(20);
+        assertEquals(Arrays.asList(new Integer[] { 2, 3, 5, 7, 11, 13, 17, 19 }), primeNumbers);
+    }
+}

apache-poi/src/main/java/com/baeldung/poi/powerpoint/PowerPointHelper.java

@@ -0,0 +1,224 @@
+package com.baeldung.poi.powerpoint;
+
+import org.apache.poi.sl.usermodel.AutoNumberingScheme;
+import org.apache.poi.sl.usermodel.PictureData;
+import org.apache.poi.sl.usermodel.TableCell;
+import org.apache.poi.sl.usermodel.TextParagraph;
+import org.apache.poi.util.IOUtils;
+import org.apache.poi.xslf.usermodel.*;
+
+import java.awt.*;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Helper class for the PowerPoint presentation creation
+ */
+public class PowerPointHelper {
+
+    /**
+     * Read an existing presentation
+     *
+     * @param fileLocation
+     *            File location of the presentation
+     * @return instance of {@link XMLSlideShow}
+     * @throws IOException
+     */
+    public XMLSlideShow readingExistingSlideShow(String fileLocation) throws IOException {
+        return new XMLSlideShow(new FileInputStream(fileLocation));
+    }
+
+    /**
+     * Create a sample presentation
+     *
+     * @param fileLocation
+     *            File location of the presentation
+     * @throws IOException
+     */
+    public void createPresentation(String fileLocation) throws IOException {
+        // Create presentation
+        XMLSlideShow ppt = new XMLSlideShow();
+
+        XSLFSlideMaster defaultMaster = ppt.getSlideMasters().get(0);
+
+        // Retriving the slide layout
+        XSLFSlideLayout layout = defaultMaster.getLayout(SlideLayout.TITLE_ONLY);
+
+        // Creating the 1st slide
+        XSLFSlide slide1 = ppt.createSlide(layout);
+        XSLFTextShape title = slide1.getPlaceholder(0);
+        // Clearing text to remove the predefined one in the template
+        title.clearText();
+        XSLFTextParagraph p = title.addNewTextParagraph();
+
+        XSLFTextRun r1 = p.addNewTextRun();
+        r1.setText("Baeldung");
+        r1.setFontColor(new Color(78, 147, 89));
+        r1.setFontSize(48.);
+
+        // Add Image
+        ClassLoader classLoader = getClass().getClassLoader();
+        byte[] pictureData = IOUtils.toByteArray(new FileInputStream(classLoader.getResource("logo-leaf.png").getFile()));
+
+        XSLFPictureData pd = ppt.addPicture(pictureData, PictureData.PictureType.PNG);
+        XSLFPictureShape picture = slide1.createPicture(pd);
+        picture.setAnchor(new Rectangle(320, 230, 100, 92));
+
+        // Creating 2nd slide
+        layout = defaultMaster.getLayout(SlideLayout.TITLE_AND_CONTENT);
+        XSLFSlide slide2 = ppt.createSlide(layout);
+
+        // setting the tile
+        title = slide2.getPlaceholder(0);
+        title.clearText();
+        XSLFTextRun r = title.addNewTextParagraph().addNewTextRun();
+        r.setText("Baeldung");
+
+        // Adding the link
+        XSLFHyperlink link = r.createHyperlink();
+        link.setAddress("http://www.baeldung.com");
+
+        // setting the content
+        XSLFTextShape content = slide2.getPlaceholder(1);
+        content.clearText(); // unset any existing text
+        content.addNewTextParagraph().addNewTextRun().setText("First paragraph");
+        content.addNewTextParagraph().addNewTextRun().setText("Second paragraph");
+        content.addNewTextParagraph().addNewTextRun().setText("Third paragraph");
+
+        // Creating 3rd slide - List
+        layout = defaultMaster.getLayout(SlideLayout.TITLE_AND_CONTENT);
+        XSLFSlide slide3 = ppt.createSlide(layout);
+        title = slide3.getPlaceholder(0);
+        title.clearText();
+        r = title.addNewTextParagraph().addNewTextRun();
+        r.setText("Lists");
+
+        content = slide3.getPlaceholder(1);
+        content.clearText();
+        XSLFTextParagraph p1 = content.addNewTextParagraph();
+        p1.setIndentLevel(0);
+        p1.setBullet(true);
+        r1 = p1.addNewTextRun();
+        r1.setText("Bullet");
+
+        // the next three paragraphs form an auto-numbered list
+        XSLFTextParagraph p2 = content.addNewTextParagraph();
+        p2.setBulletAutoNumber(AutoNumberingScheme.alphaLcParenRight, 1);
+        p2.setIndentLevel(1);
+        XSLFTextRun r2 = p2.addNewTextRun();
+        r2.setText("Numbered List Item - 1");
+
+        // Creating 4th slide
+        XSLFSlide slide4 = ppt.createSlide();
+        createTable(slide4);
+
+        // Save presentation
+        FileOutputStream out = new FileOutputStream(fileLocation);
+        ppt.write(out);
+        out.close();
+
+        // Closing presentation
+        ppt.close();
+    }
+
+    /**
+     * Delete a slide from the presentation
+     *
+     * @param ppt
+     *            The presentation
+     * @param slideNumber
+     *            The number of the slide to be deleted (0-based)
+     */
+    public void deleteSlide(XMLSlideShow ppt, int slideNumber) {
+        ppt.removeSlide(slideNumber);
+    }
+
+    /**
+     * Re-order the slides inside a presentation
+     *
+     * @param ppt
+     *            The presentation
+     * @param slideNumber
+     *            The number of the slide to move
+     * @param newSlideNumber
+     *            The new position of the slide (0-base)
+     */
+    public void reorderSlide(XMLSlideShow ppt, int slideNumber, int newSlideNumber) {
+        List<XSLFSlide> slides = ppt.getSlides();
+
+        XSLFSlide secondSlide = slides.get(slideNumber);
+        ppt.setSlideOrder(secondSlide, newSlideNumber);
+    }
+
+    /**
+     * Retrieve the placeholder inside a slide
+     * 
+     * @param slide 
+     *          The slide
+     * @return List of placeholder inside a slide
+     */
+    public List<XSLFShape> retrieveTemplatePlaceholders(XSLFSlide slide) {
+        List<XSLFShape> placeholders = new ArrayList<>();
+
+        for (XSLFShape shape : slide.getShapes()) {
+            if (shape instanceof XSLFAutoShape) {
+                placeholders.add(shape);
+            }
+        }
+        return placeholders;
+    }
+
+    /**
+     * Create a table
+     *
+     * @param slide
+     *            Slide
+     */
+    private void createTable(XSLFSlide slide) {
+
+        XSLFTable tbl = slide.createTable();
+        tbl.setAnchor(new Rectangle(50, 50, 450, 300));
+
+        int numColumns = 3;
+        int numRows = 5;
+
+        // header
+        XSLFTableRow headerRow = tbl.addRow();
+        headerRow.setHeight(50);
+        for (int i = 0; i < numColumns; i++) {
+            XSLFTableCell th = headerRow.addCell();
+            XSLFTextParagraph p = th.addNewTextParagraph();
+            p.setTextAlign(TextParagraph.TextAlign.CENTER);
+            XSLFTextRun r = p.addNewTextRun();
+            r.setText("Header " + (i + 1));
+            r.setBold(true);
+            r.setFontColor(Color.white);
+            th.setFillColor(new Color(79, 129, 189));
+            th.setBorderWidth(TableCell.BorderEdge.bottom, 2.0);
+            th.setBorderColor(TableCell.BorderEdge.bottom, Color.white);
+            // all columns are equally sized
+            tbl.setColumnWidth(i, 150);
+        }
+
+        // data
+        for (int rownum = 0; rownum < numRows; rownum++) {
+            XSLFTableRow tr = tbl.addRow();
+            tr.setHeight(50);
+            for (int i = 0; i < numColumns; i++) {
+                XSLFTableCell cell = tr.addCell();
+                XSLFTextParagraph p = cell.addNewTextParagraph();
+                XSLFTextRun r = p.addNewTextRun();
+
+                r.setText("Cell " + (i * rownum + 1));
+                if (rownum % 2 == 0) {
+                    cell.setFillColor(new Color(208, 216, 232));
+                } else {
+                    cell.setFillColor(new Color(233, 247, 244));
+                }
+            }
+        }
+    }
+}

apache-poi/src/test/java/com/baeldung/poi/powerpoint/PowerPointIntegrationTest.java

@@ -0,0 +1,77 @@
+package com.baeldung.poi.powerpoint;
+
+import org.apache.poi.xslf.usermodel.XMLSlideShow;
+import org.apache.poi.xslf.usermodel.XSLFShape;
+import org.apache.poi.xslf.usermodel.XSLFSlide;
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.File;
+import java.util.List;
+
+public class PowerPointIntegrationTest {
+
+    private PowerPointHelper pph;
+    private String fileLocation;
+    private static final String FILE_NAME = "presentation.pptx";
+
+    @Before
+    public void setUp() throws Exception {
+        File currDir = new File(".");
+        String path = currDir.getAbsolutePath();
+        fileLocation = path.substring(0, path.length() - 1) + FILE_NAME;
+
+        pph = new PowerPointHelper();
+        pph.createPresentation(fileLocation);
+    }
+
+    @Test
+    public void whenReadingAPresentation_thenOK() throws Exception {
+        XMLSlideShow xmlSlideShow = pph.readingExistingSlideShow(fileLocation);
+
+        Assert.assertNotNull(xmlSlideShow);
+        Assert.assertEquals(4, xmlSlideShow.getSlides().size());
+    }
+
+    @Test
+    public void whenRetrievingThePlaceholdersForEachSlide_thenOK() throws Exception {
+        XMLSlideShow xmlSlideShow = pph.readingExistingSlideShow(fileLocation);
+
+        List<XSLFShape> onlyTitleSlidePlaceholders = pph.retrieveTemplatePlaceholders(xmlSlideShow.getSlides().get(0));
+        List<XSLFShape> titleAndBodySlidePlaceholders = pph.retrieveTemplatePlaceholders(xmlSlideShow.getSlides().get(1));
+        List<XSLFShape> emptySlidePlaceholdes = pph.retrieveTemplatePlaceholders(xmlSlideShow.getSlides().get(3));
+
+        Assert.assertEquals(1, onlyTitleSlidePlaceholders.size());
+        Assert.assertEquals(2, titleAndBodySlidePlaceholders.size());
+        Assert.assertEquals(0, emptySlidePlaceholdes.size());
+
+    }
+
+    @Test
+    public void whenSortingSlides_thenOK() throws Exception {
+        XMLSlideShow xmlSlideShow = pph.readingExistingSlideShow(fileLocation);
+        XSLFSlide slide4 = xmlSlideShow.getSlides().get(3);
+        pph.reorderSlide(xmlSlideShow, 3, 1);
+
+        Assert.assertEquals(slide4, xmlSlideShow.getSlides().get(1));
+    }
+
+    @Test
+    public void givenPresentation_whenDeletingASlide_thenOK() throws Exception {
+        XMLSlideShow xmlSlideShow = pph.readingExistingSlideShow(fileLocation);
+        pph.deleteSlide(xmlSlideShow, 3);
+
+        Assert.assertEquals(3, xmlSlideShow.getSlides().size());
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        File testFile = new File(fileLocation);
+        if (testFile.exists()) {
+            testFile.delete();
+        }
+        pph = null;
+    }
+}

apache-spark/README.md

@@ -0,0 +1,3 @@
+### Relevant articles
+
+- [Introduction to Apache Spark](http://www.baeldung.com/apache-spark)

cas/cas-secured-app/pom.xml

@@ -65,6 +65,24 @@
 				<groupId>org.springframework.boot</groupId>
 				<artifactId>spring-boot-maven-plugin</artifactId>
 			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<version>${maven-surefire-plugin.version}</version>
+				<configuration>
+					<forkCount>3</forkCount>
+					<reuseForks>true</reuseForks>
+					<excludes>
+						<exclude>**/*IntegrationTest.java</exclude>
+						<exclude>**/*LongRunningUnitTest.java</exclude>
+						<exclude>**/*ManualTest.java</exclude>
+						<exclude>**/JdbcTest.java</exclude>
+						<exclude>**/*LiveTest.java</exclude>
+					</excludes>
+
+				</configuration>
+			</plugin>
+
 		</plugins>
 	</build>
 
@@ -107,4 +125,5 @@
 	</pluginRepositories>
 
 
+
 </project>

cas/cas-secured-app/src/main/java/com/baeldung/cassecuredapp/CasSecuredAppApplication.java

@@ -40,14 +40,14 @@ public class CasSecuredAppApplication {
 	@Primary
 	public AuthenticationEntryPoint authenticationEntryPoint(ServiceProperties sP) {
 	  CasAuthenticationEntryPoint entryPoint = new CasAuthenticationEntryPoint();
-	  entryPoint.setLoginUrl("https://localhost:8443/cas/login");
+	  entryPoint.setLoginUrl("https://localhost:6443/cas/login");
 	  entryPoint.setServiceProperties(sP);
 	  return entryPoint;
 	}
 
 	@Bean
 	public TicketValidator ticketValidator() {
-	  return new Cas30ServiceTicketValidator("https://localhost:8443/cas");
+	  return new Cas30ServiceTicketValidator("https://localhost:6443/cas");
 	}
 
 	@Bean
@@ -71,7 +71,7 @@ public class CasSecuredAppApplication {
 	@Bean
 	public LogoutFilter logoutFilter() {
 	  LogoutFilter logoutFilter = new LogoutFilter(
-	    "https://localhost:8443/cas/logout", securityContextLogoutHandler());
+	    "https://localhost:6443/cas/logout", securityContextLogoutHandler());
 	  logoutFilter.setFilterProcessesUrl("/logout/cas");
 	  return logoutFilter;
 	}
@@ -79,7 +79,7 @@ public class CasSecuredAppApplication {
 	@Bean
 	public SingleSignOutFilter singleSignOutFilter() {
 	  SingleSignOutFilter singleSignOutFilter = new SingleSignOutFilter();
-	  singleSignOutFilter.setCasServerUrlPrefix("https://localhost:8443/cas");
+	  singleSignOutFilter.setCasServerUrlPrefix("https://localhost:6443/cas");
 	  singleSignOutFilter.setIgnoreInitConfiguration(true);
 	  return singleSignOutFilter;
 	}

cas/cas-secured-app/src/test/java/com/baeldung/cassecuredapp/CasSecuredAppApplicationIntegrationTest.java

@@ -7,7 +7,7 @@ import org.springframework.test.context.junit4.SpringRunner;
 
 @RunWith(SpringRunner.class)
 @SpringBootTest
-public class CasSecuredAppApplicationTests {
+public class CasSecuredAppApplicationIntegrationTest {
 
 	@Test
 	public void contextLoads() {

cas/cas-server/src/main/resources/application.properties

@@ -2,9 +2,9 @@
 # CAS Server Context Configuration
 #
 server.context-path=/cas
-server.port=8443
+server.port=6443
 
-server.ssl.key-store=file:/etc/cas/thekeystore
+server.ssl.key-store=classpath:/etc/cas/thekeystore
 server.ssl.key-store-password=changeit
 server.ssl.key-password=changeit
 # server.ssl.ciphers=
@@ -40,6 +40,12 @@ spring.http.encoding.charset=UTF-8
 spring.http.encoding.enabled=true
 spring.http.encoding.force=true
 
+##
+#CAS CONFIG LOCATION
+#
+cas.standalone.config=classpath:/etc/cas/config
+
+
 ##
 # CAS Cloud Bus Configuration
 #
@@ -82,6 +88,7 @@ spring.thymeleaf.mode=HTML
 # CAS Log4j Configuration
 #
 # logging.config=file:/etc/cas/log4j2.xml
+
 server.context-parameters.isLog4jAutoInitializationDisabled=true
 
 ##
@@ -102,11 +109,12 @@ cas.authn.jdbc.query[0].sql=SELECT * FROM users WHERE email = ?
 cas.authn.jdbc.query[0].url=jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
 cas.authn.jdbc.query[0].dialect=org.hibernate.dialect.MySQLDialect
 cas.authn.jdbc.query[0].user=root
-cas.authn.jdbc.query[0].password=
+cas.authn.jdbc.query[0].password=root
 cas.authn.jdbc.query[0].ddlAuto=none
-cas.authn.jdbc.query[0].driverClass=com.mysql.jdbc.Driver
+#cas.authn.jdbc.query[0].driverClass=com.mysql.jdbc.Driver
+cas.authn.jdbc.query[0].driverClass=com.mysql.cj.jdbc.Driver
 cas.authn.jdbc.query[0].fieldPassword=password
-cas.authn.jdbc.query[0].passwordEncoder.type=BCRYPT
+cas.authn.jdbc.query[0].passwordEncoder.type=NONE
 
 
 ##

cas/cas-server/src/main/resources/cas.properties

@@ -1,16 +1,15 @@
-cas.server.name: https://localhost:8443
-cas.server.prefix: https://localhost:8443/cas
+cas.server.name: https://localhost:6443
+cas.server.prefix: https://localhost:643/cas
 
 cas.adminPagesSecurity.ip=127\.0\.0\.1
 
-logging.config: file:/etc/cas/config/log4j2.xml
-
 cas.serviceRegistry.initFromJson=true
 cas.serviceRegistry.config.location=classpath:/services
 
 cas.authn.accept.users=
 cas.authn.accept.name=
 
+
 #CAS Database Authentication Property
 
 # cas.authn.jdbc.query[0].healthQuery=

cas/cas-server/src/main/resources/create_test_db_and_users_tbl.sql

@@ -0,0 +1,16 @@
+-- Dumping database structure for test
+CREATE DATABASE IF NOT EXISTS `test` /*!40100 DEFAULT CHARACTER SET latin1 */;
+USE `test`;
+
+-- Dumping structure for table test.users
+CREATE TABLE IF NOT EXISTS `users` (
+  `id` int(11) NOT NULL AUTO_INCREMENT,
+  `email` varchar(50) DEFAULT NULL,
+  `password` text DEFAULT NULL,
+  PRIMARY KEY (`id`)
+) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1;
+
+/*!40000 ALTER TABLE `users` DISABLE KEYS */;
+INSERT INTO `users` (`id`, `email`, `password`) VALUES
+	(1, 'test@test.com', 'Mellon');
+/*!40000 ALTER TABLE `users` ENABLE KEYS */;

cas/cas-server/src/main/resources/etc/cas/config/application.yml

@@ -0,0 +1,2 @@
+info:
+  description: CAS Configuration

cas/cas-server/src/main/resources/etc/cas/config/cas.properties

@@ -0,0 +1,7 @@
+cas.server.name: https://cas.example.org:8443
+cas.server.prefix: https://cas.example.org:8443/cas
+
+cas.adminPagesSecurity.ip=127\.0\.0\.1
+
+logging.config: file:/etc/cas/config/log4j2.xml
+# cas.serviceRegistry.config.location: classpath:/services

cas/cas-server/src/main/resources/etc/cas/config/log4j2.xml

@@ -0,0 +1,117 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!-- Specify the refresh internal in seconds. -->
+<Configuration monitorInterval="5" packages="org.apereo.cas.logging">
+    <Properties>
+        <!-- 
+        Default log directory is the current directory but that can be overridden with -Dcas.log.dir=<logdir>
+        Or you can change this property to a new default
+        -->
+        <Property name="cas.log.dir" >.</Property>
+        <!-- To see more CAS specific logging, adjust this property to info or debug or run server with -Dcas.log.leve=debug -->
+        <Property name="cas.log.level" >warn</Property>
+    </Properties>
+    <Appenders>
+        <Console name="console" target="SYSTEM_OUT">
+            <PatternLayout pattern="%d %p [%c] - &lt;%m&gt;%n"/>
+        </Console>
+        <RollingFile name="file" fileName="${sys:cas.log.dir}/cas.log" append="true"
+                     filePattern="${sys:cas.log.dir}/cas-%d{yyyy-MM-dd-HH}-%i.log">
+            <PatternLayout pattern="%d %p [%c] - &lt;%m&gt;%n"/>
+            <Policies>
+                <OnStartupTriggeringPolicy />
+                <SizeBasedTriggeringPolicy size="10 MB"/>
+                <TimeBasedTriggeringPolicy />
+            </Policies>
+        </RollingFile>
+        <RollingFile name="auditlogfile" fileName="${sys:cas.log.dir}/cas_audit.log" append="true"
+                     filePattern="${sys:cas.log.dir}/cas_audit-%d{yyyy-MM-dd-HH}-%i.log">
+            <PatternLayout pattern="%d %p [%c] - %m%n"/>
+            <Policies>
+                <OnStartupTriggeringPolicy />
+                <SizeBasedTriggeringPolicy size="10 MB"/>
+                <TimeBasedTriggeringPolicy />
+            </Policies>
+        </RollingFile>
+
+        <RollingFile name="perfFileAppender" fileName="${sys:cas.log.dir}/perfStats.log" append="true"
+                     filePattern="${sys:cas.log.dir}/perfStats-%d{yyyy-MM-dd-HH}-%i.log">
+            <PatternLayout pattern="%m%n"/>
+            <Policies>
+                <OnStartupTriggeringPolicy />
+                <SizeBasedTriggeringPolicy size="10 MB"/>
+                <TimeBasedTriggeringPolicy />
+            </Policies>
+        </RollingFile>
+
+        <CasAppender name="casAudit">
+            <AppenderRef ref="auditlogfile" />
+        </CasAppender>
+        <CasAppender name="casFile">
+            <AppenderRef ref="file" />
+        </CasAppender>
+        <CasAppender name="casConsole">
+            <AppenderRef ref="console" />
+        </CasAppender>
+        <CasAppender name="casPerf">
+            <AppenderRef ref="perfFileAppender" />
+        </CasAppender>
+    </Appenders>
+    <Loggers>
+        <!-- If adding a Logger with level set higher than warn, make category as selective as possible -->
+        <!-- Loggers inherit appenders from Root Logger unless additivity is false -->
+        <AsyncLogger name="org.apereo" level="${sys:cas.log.level}" includeLocation="true"/>
+        <AsyncLogger name="org.apereo.services.persondir" level="${sys:cas.log.level}" includeLocation="true"/>
+        <AsyncLogger name="org.apereo.cas.web.flow" level="info" includeLocation="true"/>
+        <AsyncLogger name="org.apache" level="warn" />
+        <AsyncLogger name="org.apache.http" level="error" />
+        <AsyncLogger name="org.springframework" level="warn" />
+        <AsyncLogger name="org.springframework.cloud.server" level="warn" />
+        <AsyncLogger name="org.springframework.cloud.client" level="warn" />
+        <AsyncLogger name="org.springframework.cloud.bus" level="warn" />
+        <AsyncLogger name="org.springframework.aop" level="warn" />
+        <AsyncLogger name="org.springframework.boot" level="warn" />
+        <AsyncLogger name="org.springframework.boot.actuate.autoconfigure" level="warn" />
+        <AsyncLogger name="org.springframework.webflow" level="warn" />
+        <AsyncLogger name="org.springframework.session" level="warn" />
+        <AsyncLogger name="org.springframework.amqp" level="error" />
+        <AsyncLogger name="org.springframework.integration" level="warn" />
+        <AsyncLogger name="org.springframework.messaging" level="warn" />
+        <AsyncLogger name="org.springframework.web" level="warn" />
+        <AsyncLogger name="org.springframework.orm.jpa" level="warn" />
+        <AsyncLogger name="org.springframework.scheduling" level="warn" />
+        <AsyncLogger name="org.springframework.context.annotation" level="error" />
+        <AsyncLogger name="org.springframework.boot.devtools" level="error" />
+        <AsyncLogger name="org.springframework.web.socket" level="warn" />
+        <AsyncLogger name="org.thymeleaf" level="warn" />
+        <AsyncLogger name="org.pac4j" level="warn" />
+        <AsyncLogger name="org.opensaml" level="warn"/>
+        <AsyncLogger name="net.sf.ehcache" level="warn" />
+        <AsyncLogger name="com.couchbase" level="warn" includeLocation="true"/>
+        <AsyncLogger name="com.ryantenney.metrics" level="warn" />
+        <AsyncLogger name="net.jradius" level="warn" />
+        <AsyncLogger name="org.openid4java" level="warn" />
+        <AsyncLogger name="org.ldaptive" level="warn" />
+        <AsyncLogger name="com.hazelcast" level="warn" />
+        <AsyncLogger name="org.jasig.spring" level="warn" />
+
+        <!-- Log perf stats only to perfStats.log -->
+        <AsyncLogger name="perfStatsLogger" level="info" additivity="false" includeLocation="true">
+            <AppenderRef ref="casPerf"/>
+        </AsyncLogger>
+
+        <!-- Log audit to all root appenders, and also to audit log (additivity is not false) -->
+        <AsyncLogger name="org.apereo.inspektr.audit.support" level="info" includeLocation="true" >
+            <AppenderRef ref="casAudit"/>
+        </AsyncLogger>
+
+        <!-- All Loggers inherit appenders specified here, unless additivity="false" on the Logger -->
+        <AsyncRoot level="warn">
+            <AppenderRef ref="casFile"/>
+            <!-- 
+                 For deployment to an application server running as service, 
+                 delete the casConsole appender below
+            -->
+            <AppenderRef ref="casConsole"/>
+        </AsyncRoot>
+    </Loggers>
+</Configuration>

core-java-8/README.md

@@ -30,3 +30,5 @@
 - [The Difference Between map() and flatMap()](http://www.baeldung.com/java-difference-map-and-flatmap)
 - [Merging Streams in Java](http://www.baeldung.com/java-merge-streams)
 - [“Stream has already been operated upon or closed” Exception in Java](http://www.baeldung.com/java-stream-operated-upon-or-closed-exception)
+- [Display All Time Zones With GMT And UTC in Java](http://www.baeldung.com/java-time-zones)
+- [Copy a File with Java](http://www.baeldung.com/java-copy-file)

core-java-8/src/main/java/com/baeldung/annotations/ClassWithAnnotation.java

@@ -0,0 +1,5 @@
+package com.baeldung.annotations;
+
+@Deprecated
+class ClassWithAnnotation {
+}

core-java-8/src/main/java/com/baeldung/annotations/ClassWithDeprecatedMethod.java

@@ -0,0 +1,9 @@
+package com.baeldung.annotations;
+
+class ClassWithDeprecatedMethod {
+
+    @Deprecated
+    static void deprecatedMethod() {
+
+    }
+}

core-java-8/src/main/java/com/baeldung/annotations/ClassWithSafeVarargs.java

@@ -0,0 +1,11 @@
+package com.baeldung.annotations;
+
+class ClassWithSafeVarargs<T> {
+
+    @SafeVarargs
+    final void iterateOverVarargs(T... args) {
+        for (T x : args) {
+            // do stuff with x
+        }
+    }
+}

core-java-8/src/main/java/com/baeldung/annotations/ClassWithSuppressWarnings.java

@@ -0,0 +1,9 @@
+package com.baeldung.annotations;
+
+class ClassWithSuppressWarnings {
+
+    @SuppressWarnings("deprecation")
+    void useDeprecatedMethod() {
+        ClassWithDeprecatedMethod.deprecatedMethod(); // no warning is generated here
+    }
+}

core-java-8/src/main/java/com/baeldung/annotations/IntConsumer.java

@@ -0,0 +1,8 @@
+package com.baeldung.annotations;
+
+@FunctionalInterface
+interface IntConsumer {
+
+    void accept(Integer number);
+
+}

core-java-8/src/main/java/com/baeldung/annotations/Interval.java

@@ -0,0 +1,8 @@
+package com.baeldung.annotations;
+
+import java.lang.annotation.Repeatable;
+
+@Repeatable(Intervals.class)
+@interface Interval {
+    int hour() default 1;
+}

core-java-8/src/main/java/com/baeldung/annotations/IntervalUsage.java

@@ -0,0 +1,9 @@
+package com.baeldung.annotations;
+
+public class IntervalUsage {
+
+    @Interval(hour = 17)
+    @Interval(hour = 13)
+    void doPeriodicCleanup() {
+    }
+}

core-java-8/src/main/java/com/baeldung/annotations/Intervals.java

@@ -0,0 +1,5 @@
+package com.baeldung.annotations;
+
+@interface Intervals {
+    Interval[] value();
+}

core-java-8/src/main/java/com/baeldung/annotations/MyAnnotation.java

@@ -0,0 +1,11 @@
+package com.baeldung.annotations;
+
+import java.lang.annotation.*;
+
+@Inherited
+@Documented
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.LOCAL_VARIABLE, ElementType.FIELD})
+@interface MyAnnotation {
+
+}

core-java-8/src/main/java/com/baeldung/annotations/MyAnnotationTarget.java

@@ -0,0 +1,16 @@
+package com.baeldung.annotations;
+
+class MyAnnotationTarget {
+
+    // this is OK
+    @MyAnnotation
+    String someField;
+
+    // @MyAnnotation <- this is invalid usage!
+    void doSomething() {
+
+        // this also works
+        @MyAnnotation
+        String localVariable;
+    }
+}

core-java-8/src/main/java/com/baeldung/annotations/MyOperation.java

@@ -0,0 +1,6 @@
+package com.baeldung.annotations;
+
+interface MyOperation {
+
+    void perform();
+}

core-java-8/src/main/java/com/baeldung/annotations/MyOperationImpl.java

@@ -0,0 +1,9 @@
+package com.baeldung.annotations;
+
+class MyOperationImpl implements MyOperation {
+
+    @Override
+    public void perform() {
+
+    }
+}

core-java-8/src/main/java/com/baeldung/prime/PrimeGenerator.java

@@ -0,0 +1,59 @@
+package com.baeldung.prime;
+
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class PrimeGenerator {
+    public static List<Integer> sieveOfEratosthenes(int n) {
+        final boolean prime[] = new boolean[n + 1];
+        Arrays.fill(prime, true);
+
+        for (int p = 2; p * p <= n; p++) {
+            if (prime[p]) {
+                for (int i = p * 2; i <= n; i += p)
+                    prime[i] = false;
+            }
+        }
+
+        final List<Integer> primes = new LinkedList<>();
+        for (int i = 2; i <= n; i++) {
+            if (prime[i])
+                primes.add(i);
+        }
+        return primes;
+    }
+
+    public static List<Integer> primeNumbersBruteForce(int max) {
+        final List<Integer> primeNumbers = new LinkedList<Integer>();
+        for (int i = 2; i <= max; i++) {
+            if (isPrimeBruteForce(i)) {
+                primeNumbers.add(i);
+            }
+        }
+        return primeNumbers;
+    }
+
+    private static boolean isPrimeBruteForce(int x) {
+        for (int i = 2; i < x; i++) {
+            if (x % i == 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public static List<Integer> primeNumbersTill(int max) {
+        return IntStream.rangeClosed(2, max)
+            .filter(x -> isPrime(x))
+            .boxed()
+            .collect(Collectors.toList());
+    }
+
+    private static boolean isPrime(int x) {
+        return IntStream.rangeClosed(2, (int) (Math.sqrt(x)))
+            .allMatch(n -> x % n != 0);
+    }
+}

core-java-8/src/main/java/com/baeldung/timezonedisplay/TimezoneDisplay.java

@@ -0,0 +1,55 @@
+package com.baeldung.timezonedisplay;
+
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.ZoneOffset;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+public class TimezoneDisplay {
+
+    public enum OffsetBase {
+        GMT, UTC
+    }
+
+    public List<String> getTimeZoneList(OffsetBase base) {
+        Set<String> availableZoneIds = ZoneId.getAvailableZoneIds();
+
+        LocalDateTime now = LocalDateTime.now();
+        return availableZoneIds
+          .stream()
+          .map(ZoneId::of)
+          .sorted(new ZoneComparator())
+          .map(id -> String.format("(%s%s) %s", base, getOffset(now, id), id.getId()))
+          .collect(Collectors.toList());
+    }
+
+    private String getOffset(LocalDateTime dateTime, ZoneId id) {
+        return dateTime
+          .atZone(id)
+          .getOffset()
+          .getId()
+          .replace("Z", "+00:00");
+    }
+
+    private class ZoneComparator implements Comparator<ZoneId> {
+
+        @Override
+        public int compare(ZoneId zoneId1, ZoneId zoneId2) {
+            LocalDateTime now = LocalDateTime.now();
+
+            ZoneOffset offset1 = now
+              .atZone(zoneId1)
+              .getOffset();
+
+            ZoneOffset offset2 = now
+              .atZone(zoneId2)
+              .getOffset();
+
+            return offset1.compareTo(offset2);
+        }
+    }
+
+}

core-java-8/src/main/java/com/baeldung/timezonedisplay/TimezoneDisplayApp.java

@@ -0,0 +1,18 @@
+package com.baeldung.timezonedisplay;
+
+import java.util.List;
+
+public class TimezoneDisplayApp {
+
+    public static void main(String... args) {
+        TimezoneDisplay display = new TimezoneDisplay();
+
+        System.out.println("Time zones in UTC:");
+        List<String> utc = display.getTimeZoneList(TimezoneDisplay.OffsetBase.UTC);
+        utc.forEach(System.out::println);
+
+        System.out.println("Time zones in GMT:");
+        List<String> gmt = display.getTimeZoneList(TimezoneDisplay.OffsetBase.GMT);
+        gmt.forEach(System.out::println);
+    }
+}

core-java-8/src/test/java/com/baeldung/prime/PrimeGeneratorTest.java

@@ -0,0 +1,28 @@
+package com.baeldung.prime;
+
+import static com.baeldung.prime.PrimeGenerator.*;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class PrimeGeneratorTest {
+    @Test
+    public void whenBruteForced_returnsSuccessfully() {
+        final List<Integer> primeNumbers = primeNumbersBruteForce(20);
+        assertEquals(Arrays.asList(new Integer[] { 2, 3, 5, 7, 11, 13, 17, 19 }), primeNumbers);
+    }
+
+    @Test
+    public void whenOptimized_returnsSuccessfully() {
+        final List<Integer> primeNumbers = primeNumbersTill(20);
+        assertEquals(Arrays.asList(new Integer[] { 2, 3, 5, 7, 11, 13, 17, 19 }), primeNumbers);
+    }
+
+    @Test
+    public void whenSieveOfEratosthenes_returnsSuccessfully() {
+        final List<Integer> primeNumbers = sieveOfEratosthenes(20);
+        assertEquals(Arrays.asList(new Integer[] { 2, 3, 5, 7, 11, 13, 17, 19 }), primeNumbers);
+    }
+}

core-java-9/src/main/java/com/baeldung/java9/datetime/DateToLocalDateConverter.java

@@ -0,0 +1,39 @@
+/**
+ * 
+ */
+package com.baeldung.java9.datetime;
+
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.ZoneId;
+import java.util.Date;
+
+/**
+ * Class which shows a way to convert java.util.Date into java.time.LocalDate.
+ * 
+ * @author abialas
+ *
+ */
+public class DateToLocalDateConverter {
+
+    public static LocalDate convertToLocalDateViaInstant(Date dateToConvert) {
+        return dateToConvert.toInstant()
+            .atZone(ZoneId.systemDefault())
+            .toLocalDate();
+    }
+
+    public static LocalDate convertToLocalDateViaSqlDate(Date dateToConvert) {
+        return new java.sql.Date(dateToConvert.getTime()).toLocalDate();
+    }
+
+    public static LocalDate convertToLocalDateViaMilisecond(Date dateToConvert) {
+        return Instant.ofEpochMilli(dateToConvert.getTime())
+            .atZone(ZoneId.systemDefault())
+            .toLocalDate();
+    }
+
+    public static LocalDate convertToLocalDate(Date dateToConvert) {
+        return LocalDate.ofInstant(dateToConvert.toInstant(), ZoneId.systemDefault());
+    }
+
+}

core-java-9/src/main/java/com/baeldung/java9/datetime/DateToLocalDateTimeConverter.java

@@ -0,0 +1,39 @@
+/**
+ * 
+ */
+package com.baeldung.java9.datetime;
+
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.util.Date;
+
+/**
+ * Class which shows a way to convert java.util.Date into java.time.LocalDateTime.
+ * 
+ * @author abialas
+ *
+ */
+public class DateToLocalDateTimeConverter {
+
+    public static LocalDateTime convertToLocalDateTimeViaInstant(Date dateToConvert) {
+        return dateToConvert.toInstant()
+            .atZone(ZoneId.systemDefault())
+            .toLocalDateTime();
+    }
+
+    public static LocalDateTime convertToLocalDateTimeViaSqlTimestamp(Date dateToConvert) {
+        return new java.sql.Timestamp(dateToConvert.getTime()).toLocalDateTime();
+    }
+
+    public static LocalDateTime convertToLocalDateTimeViaMilisecond(Date dateToConvert) {
+        return Instant.ofEpochMilli(dateToConvert.getTime())
+            .atZone(ZoneId.systemDefault())
+            .toLocalDateTime();
+    }
+
+    public static LocalDateTime convertToLocalDateTime(Date dateToConvert) {
+        return LocalDateTime.ofInstant(dateToConvert.toInstant(), ZoneId.systemDefault());
+    }
+
+}

core-java-9/src/main/java/com/baeldung/java9/datetime/LocalDateTimeToDateConverter.java

@@ -0,0 +1,27 @@
+/**
+ * 
+ */
+package com.baeldung.java9.datetime;
+
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.util.Date;
+
+/**
+ * Class which shows different ways of converting java.time.LocalDateTime into java.util.Date. 
+ *  
+ * @author abialas
+ *
+ */
+public class LocalDateTimeToDateConverter {
+
+    public static Date convertToDateViaSqlTimestamp(LocalDateTime dateToConvert) {
+        return java.sql.Timestamp.valueOf(dateToConvert);
+    }
+
+    public static Date convertToDateViaInstant(LocalDateTime dateToConvert) {
+        return java.util.Date.from(dateToConvert.atZone(ZoneId.systemDefault())
+            .toInstant());
+    }
+
+}

core-java-9/src/main/java/com/baeldung/java9/datetime/LocalDateToDateConverter.java

@@ -0,0 +1,28 @@
+/**
+ * 
+ */
+package com.baeldung.java9.datetime;
+
+import java.time.LocalDate;
+import java.time.ZoneId;
+import java.util.Date;
+
+/**
+ * Class which shows different ways of converting java.time.LocalDate into java.util.Date. 
+ *  
+ * @author abialas
+ *
+ */
+public class LocalDateToDateConverter {
+
+    public static Date convertToDateViaSqlDate(LocalDate dateToConvert) {
+        return java.sql.Date.valueOf(dateToConvert);
+    }
+
+    public static Date convertToDateViaInstant(LocalDate dateToConvert) {
+        return java.util.Date.from(dateToConvert.atStartOfDay()
+            .atZone(ZoneId.systemDefault())
+            .toInstant());
+    }
+
+}

core-java-9/src/test/java/com/baeldung/java9/datetime/DateToLocalDateConverterTest.java

@@ -0,0 +1,89 @@
+/**
+ * 
+ */
+package com.baeldung.java9.datetime;
+
+import static org.junit.Assert.assertEquals;
+
+import java.time.LocalDate;
+import java.time.temporal.ChronoField;
+import java.util.Calendar;
+import java.util.Date;
+
+import org.junit.Test;
+
+import com.baeldung.java9.datetime.DateToLocalDateConverter;
+
+/**
+ * JUnits for {@link DateToLocalDateConverter} class.
+ * 
+ * @author abialas
+ *
+ */
+public class DateToLocalDateConverterTest {
+
+    @Test
+    public void shouldReturn10thNovember2010WhenConvertViaInstant() {
+        // given
+        Calendar calendar = Calendar.getInstance();
+        calendar.set(2010, 10, 10);
+        Date dateToConvert = calendar.getTime();
+
+        // when
+        LocalDate localDate = DateToLocalDateConverter.convertToLocalDateViaInstant(dateToConvert);
+
+        // then
+        assertEquals(2010, localDate.get(ChronoField.YEAR));
+        assertEquals(11, localDate.get(ChronoField.MONTH_OF_YEAR));
+        assertEquals(10, localDate.get(ChronoField.DAY_OF_MONTH));
+    }
+
+    @Test
+    public void shouldReturn10thNovember2010WhenConvertViaMiliseconds() {
+        // given
+        Calendar calendar = Calendar.getInstance();
+        calendar.set(2010, 10, 10);
+        Date dateToConvert = calendar.getTime();
+
+        // when
+        LocalDate localDate = DateToLocalDateConverter.convertToLocalDateViaMilisecond(dateToConvert);
+
+        // then
+        assertEquals(2010, localDate.get(ChronoField.YEAR));
+        assertEquals(11, localDate.get(ChronoField.MONTH_OF_YEAR));
+        assertEquals(10, localDate.get(ChronoField.DAY_OF_MONTH));
+    }
+
+    @Test
+    public void shouldReturn10thNovember2010WhenConvertViaSqlDate() {
+        // given
+        Calendar calendar = Calendar.getInstance();
+        calendar.set(2010, 10, 10);
+        Date dateToConvert = calendar.getTime();
+
+        // when
+        LocalDate localDate = DateToLocalDateConverter.convertToLocalDateViaSqlDate(dateToConvert);
+
+        // then
+        assertEquals(2010, localDate.get(ChronoField.YEAR));
+        assertEquals(11, localDate.get(ChronoField.MONTH_OF_YEAR));
+        assertEquals(10, localDate.get(ChronoField.DAY_OF_MONTH));
+    }
+
+    @Test
+    public void shouldReturn10thNovember2010WhenConvertToLocalDate() {
+        // given
+        Calendar calendar = Calendar.getInstance();
+        calendar.set(2010, 10, 10);
+        Date dateToConvert = calendar.getTime();
+
+        // when
+        LocalDate localDateTime = DateToLocalDateConverter.convertToLocalDate(dateToConvert);
+
+        // then
+        assertEquals(2010, localDateTime.get(ChronoField.YEAR));
+        assertEquals(11, localDateTime.get(ChronoField.MONTH_OF_YEAR));
+        assertEquals(10, localDateTime.get(ChronoField.DAY_OF_MONTH));
+    }
+
+}

core-java-9/src/test/java/com/baeldung/java9/datetime/DateToLocalDateTimeConverterTest.java

@@ -0,0 +1,97 @@
+/**
+ * 
+ */
+package com.baeldung.java9.datetime;
+
+import static org.junit.Assert.assertEquals;
+
+import java.time.LocalDateTime;
+import java.time.temporal.ChronoField;
+import java.util.Calendar;
+import java.util.Date;
+
+import org.junit.Test;
+
+import com.baeldung.java9.datetime.DateToLocalDateTimeConverter;
+
+/**
+ * JUnits for {@link DateToLocalDateTimeConverter} class.
+ * 
+ * @author abialas
+ *
+ */
+public class DateToLocalDateTimeConverterTest {
+
+    @Test
+    public void shouldReturn10thNovember2010time8hour20minWhenConvertViaInstant() {
+        // given
+        Calendar calendar = Calendar.getInstance();
+        calendar.set(2010, 10, 10, 8, 20);
+        Date dateToConvert = calendar.getTime();
+
+        // when
+        LocalDateTime localDateTime = DateToLocalDateTimeConverter.convertToLocalDateTimeViaInstant(dateToConvert);
+
+        // then
+        assertEquals(2010, localDateTime.get(ChronoField.YEAR));
+        assertEquals(11, localDateTime.get(ChronoField.MONTH_OF_YEAR));
+        assertEquals(10, localDateTime.get(ChronoField.DAY_OF_MONTH));
+        assertEquals(8, localDateTime.get(ChronoField.HOUR_OF_DAY));
+        assertEquals(20, localDateTime.get(ChronoField.MINUTE_OF_HOUR));
+    }
+
+    @Test
+    public void shouldReturn10thNovember2010time8hour20minWhenConvertViaMiliseconds() {
+        // given
+        Calendar calendar = Calendar.getInstance();
+        calendar.set(2010, 10, 10, 8, 20);
+        Date dateToConvert = calendar.getTime();
+
+        // when
+        LocalDateTime localDateTime = DateToLocalDateTimeConverter.convertToLocalDateTimeViaMilisecond(dateToConvert);
+
+        // then
+        assertEquals(2010, localDateTime.get(ChronoField.YEAR));
+        assertEquals(11, localDateTime.get(ChronoField.MONTH_OF_YEAR));
+        assertEquals(10, localDateTime.get(ChronoField.DAY_OF_MONTH));
+        assertEquals(8, localDateTime.get(ChronoField.HOUR_OF_DAY));
+        assertEquals(20, localDateTime.get(ChronoField.MINUTE_OF_HOUR));
+    }
+
+    @Test
+    public void shouldReturn10thNovember2010time8hour20minWhenConvertViaSqlTimestamp() {
+        // given
+        Calendar calendar = Calendar.getInstance();
+        calendar.set(2010, 10, 10, 8, 20);
+        Date dateToConvert = calendar.getTime();
+
+        // when
+        LocalDateTime localDateTime = DateToLocalDateTimeConverter.convertToLocalDateTimeViaSqlTimestamp(dateToConvert);
+
+        // then
+        assertEquals(2010, localDateTime.get(ChronoField.YEAR));
+        assertEquals(11, localDateTime.get(ChronoField.MONTH_OF_YEAR));
+        assertEquals(10, localDateTime.get(ChronoField.DAY_OF_MONTH));
+        assertEquals(8, localDateTime.get(ChronoField.HOUR_OF_DAY));
+        assertEquals(20, localDateTime.get(ChronoField.MINUTE_OF_HOUR));
+    }
+
+    @Test
+    public void shouldReturn10thNovember2010time8hour20minWhenConvertToLocalDateTime() {
+        // given
+        Calendar calendar = Calendar.getInstance();
+        calendar.set(2010, 10, 10, 8, 20);
+        Date dateToConvert = calendar.getTime();
+
+        // when
+        LocalDateTime localDateTime = DateToLocalDateTimeConverter.convertToLocalDateTime(dateToConvert);
+
+        // then
+        assertEquals(2010, localDateTime.get(ChronoField.YEAR));
+        assertEquals(11, localDateTime.get(ChronoField.MONTH_OF_YEAR));
+        assertEquals(10, localDateTime.get(ChronoField.DAY_OF_MONTH));
+        assertEquals(8, localDateTime.get(ChronoField.HOUR_OF_DAY));
+        assertEquals(20, localDateTime.get(ChronoField.MINUTE_OF_HOUR));
+    }
+
+}

core-java-9/src/test/java/com/baeldung/java9/datetime/LocalDateTimeToDateConverterTest.java

@@ -0,0 +1,61 @@
+/**
+ * 
+ */
+package com.baeldung.java9.datetime;
+
+import static org.junit.Assert.assertEquals;
+
+import java.time.LocalDateTime;
+import java.util.Calendar;
+import java.util.Date;
+
+import org.junit.Test;
+
+/**
+ * 
+ * JUnits for {@link LocalDateTimeToDateConverter} class.
+ * 
+ * @author abialas
+ *
+ */
+public class LocalDateTimeToDateConverterTest {
+
+    @Test
+    public void shouldReturn10thNovember2010time8hour20minWhenConvertViaInstant() {
+        // given
+        LocalDateTime dateToConvert = LocalDateTime.of(2010, 11, 10, 8, 20);
+
+        // when
+        Date date = LocalDateTimeToDateConverter.convertToDateViaInstant(dateToConvert);
+        Calendar calendar = Calendar.getInstance();
+        calendar.setTime(date);
+
+        // then
+        assertEquals(2010, calendar.get(Calendar.YEAR));
+        assertEquals(10, calendar.get(Calendar.MONTH));
+        assertEquals(10, calendar.get(Calendar.DAY_OF_MONTH));
+        assertEquals(8, calendar.get(Calendar.HOUR));
+        assertEquals(20, calendar.get(Calendar.MINUTE));
+        assertEquals(0, calendar.get(Calendar.SECOND));
+    }
+
+    @Test
+    public void shouldReturn10thNovember2010WhenConvertViaSqlTimestamp() {
+        // given
+        LocalDateTime dateToConvert = LocalDateTime.of(2010, 11, 10, 8, 20);
+
+        // when
+        Date date = LocalDateTimeToDateConverter.convertToDateViaSqlTimestamp(dateToConvert);
+        Calendar calendar = Calendar.getInstance();
+        calendar.setTime(date);
+
+        // then
+        assertEquals(2010, calendar.get(Calendar.YEAR));
+        assertEquals(10, calendar.get(Calendar.MONTH));
+        assertEquals(10, calendar.get(Calendar.DAY_OF_MONTH));
+        assertEquals(8, calendar.get(Calendar.HOUR));
+        assertEquals(20, calendar.get(Calendar.MINUTE));
+        assertEquals(0, calendar.get(Calendar.SECOND));
+    }
+
+}

core-java-9/src/test/java/com/baeldung/java9/datetime/LocalDateToDateConverterTest.java

@@ -0,0 +1,55 @@
+/**
+ * 
+ */
+package com.baeldung.java9.datetime;
+
+import static org.junit.Assert.assertEquals;
+
+import java.time.LocalDate;
+import java.util.Calendar;
+import java.util.Date;
+
+import org.junit.Test;
+
+/**
+ * 
+ * JUnits for {@link LocalDateToDateConverter} class.
+ * 
+ * @author abialas
+ *
+ */
+public class LocalDateToDateConverterTest {
+
+    @Test
+    public void shouldReturn10thNovember2010WhenConvertViaInstant() {
+        // given
+        LocalDate dateToConvert = LocalDate.of(2010, 11, 10);
+
+        // when
+        Date date = LocalDateToDateConverter.convertToDateViaInstant(dateToConvert);
+        Calendar calendar = Calendar.getInstance();
+        calendar.setTime(date);
+
+        // then
+        assertEquals(2010, calendar.get(Calendar.YEAR));
+        assertEquals(10, calendar.get(Calendar.MONTH));
+        assertEquals(10, calendar.get(Calendar.DAY_OF_MONTH));
+    }
+
+    @Test
+    public void shouldReturn10thNovember2010WhenConvertViaSqlDate() {
+        // given
+        LocalDate dateToConvert = LocalDate.of(2010, 11, 10);
+
+        // when
+        Date date = LocalDateToDateConverter.convertToDateViaSqlDate(dateToConvert);
+        Calendar calendar = Calendar.getInstance();
+        calendar.setTime(date);
+
+        // then
+        assertEquals(2010, calendar.get(Calendar.YEAR));
+        assertEquals(10, calendar.get(Calendar.MONTH));
+        assertEquals(10, calendar.get(Calendar.DAY_OF_MONTH));
+    }
+
+}

core-java-concurrency/README.md

@@ -30,3 +30,4 @@
 - [Guide to Volatile Keyword in Java](http://www.baeldung.com/java-volatile)
 - [Overview of the java.util.concurrent](http://www.baeldung.com/java-util-concurrent)
 - [Semaphores in Java](http://www.baeldung.com/java-semaphore)
+- [Daemon Threads in Java](http://www.baeldung.com/java-daemon-thread)

core-java-concurrency/src/main/java/com/baeldung/concurrent/daemon/NewThread.java

@@ -3,7 +3,6 @@ package com.baeldung.concurrent.daemon;
 public class NewThread extends Thread {
 
     public void run() {
-    	
     	long startTime = System.currentTimeMillis();
         while (true) {
             for (int i = 0; i < 10; i++) {

core-java-concurrency/src/main/java/com/baeldung/concurrent/stopping/ControlSubThread.java

@@ -0,0 +1,52 @@
+package com.baeldung.concurrent.stopping;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+public class ControlSubThread implements Runnable {
+
+    private Thread worker;
+    private int interval = 100;
+    private AtomicBoolean running = new AtomicBoolean(false);
+    private AtomicBoolean stopped = new AtomicBoolean(true);
+
+
+    public ControlSubThread(int sleepInterval) {
+        interval = sleepInterval;
+    }
+
+    public void start() {
+        worker = new Thread(this);
+        worker.start();
+    }
+
+    public void stop() {
+        running.set(false);
+    }
+
+    public void interrupt() {
+        running.set(false);
+        worker.interrupt();
+    }
+
+    boolean isRunning() {
+        return running.get();
+    }
+
+    boolean isStopped() {
+        return stopped.get();
+    }
+
+    public void run() {
+        running.set(true);
+        stopped.set(false);
+        while (running.get()) {
+            try {
+                Thread.sleep(interval);
+            } catch (InterruptedException e) {
+                // no-op, just loop again
+            }
+            // do something
+        }
+        stopped.set(true);
+    }
+}

core-java-concurrency/src/test/java/com/baeldung/concurrent/runnable/RunnableVsThreadLiveTest.java

@@ -1,24 +1,21 @@
 package com.baeldung.concurrent.runnable;
 
 import java.util.concurrent.Callable;
-import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
 
 import org.apache.commons.lang3.RandomUtils;
-import org.junit.After;
 import org.junit.AfterClass;
-import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public class RunnableVsThreadTest {
+public class RunnableVsThreadLiveTest {
 
 	private static Logger log = 
-	  LoggerFactory.getLogger(RunnableVsThreadTest.class);
+	  LoggerFactory.getLogger(RunnableVsThreadLiveTest.class);
 
 	private static ExecutorService executorService;
 	
@@ -77,9 +74,7 @@ public class RunnableVsThreadTest {
 	public void givenACallableAsLambda_whenSubmitToES_thenResult() 
 	  throws Exception {
 		
-		Future<Integer> future = executorService.submit(() -> {
-		  return RandomUtils.nextInt(0, 100);
-		});
+		Future<Integer> future = executorService.submit(() -> RandomUtils.nextInt(0, 100));
 		
 		log.info("Result from callable: {}", future.get());
 	}
@@ -99,7 +94,7 @@ class SimpleThread extends Thread{
 	
 	private String message;
 	
-	public SimpleThread(String message) {
+	SimpleThread(String message) {
 		this.message = message;
 	}
 	
@@ -116,7 +111,7 @@ class SimpleRunnable implements Runnable {
 	
 	private String message;
 	
-	public SimpleRunnable(String message) {
+	SimpleRunnable(String message) {
 		this.message = message;
 	}
 	

core-java-concurrency/src/test/java/com/baeldung/concurrent/stopping/StopThreadTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.concurrent.stopping;
+
+import com.jayway.awaitility.Awaitility;
+import org.junit.Test;
+
+import java.util.concurrent.TimeUnit;
+
+import static com.jayway.awaitility.Awaitility.await;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class StopThreadTest {
+
+    @Test
+    public void whenStoppedThreadIsStopped() throws InterruptedException {
+
+        int interval = 100;
+
+        ControlSubThread controlSubThread = new ControlSubThread(interval);
+        controlSubThread.start();
+
+        // Give things a chance to get set up
+        Thread.sleep(interval);
+        assertTrue(controlSubThread.isRunning());
+        assertFalse(controlSubThread.isStopped());
+
+        // Stop it and make sure the flags have been reversed
+        controlSubThread.stop();
+        await()
+          .until(() -> assertTrue(controlSubThread.isStopped()));
+    }
+
+    @Test
+    public void whenInterruptedThreadIsStopped() throws InterruptedException {
+
+        int interval = 5000;
+
+        ControlSubThread controlSubThread = new ControlSubThread(interval);
+        controlSubThread.start();
+
+        // Give things a chance to get set up
+        Thread.sleep(100);
+        assertTrue(controlSubThread.isRunning());
+        assertFalse(controlSubThread.isStopped());
+
+        // Stop it and make sure the flags have been reversed
+        controlSubThread.interrupt();
+
+        // Wait less than the time we would normally sleep, and make sure we exited.
+        Awaitility.await()
+          .atMost(interval/ 10, TimeUnit.MILLISECONDS)
+          .until(controlSubThread::isStopped);
+    }
+}

core-java-sun/.gitignore

@@ -0,0 +1,26 @@
+*.class
+
+0.*
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+.resourceCache
+
+# Packaged files #
+*.jar
+*.war
+*.ear
+
+# Files generated by integration tests
+*.txt
+backup-pom.xml
+/bin/
+/temp
+
+#IntelliJ specific
+.idea/
+*.iml

core-java-sun/README.md

@@ -0,0 +1,6 @@
+=========
+
+## Core Java Cookbooks and Examples
+
+### Relevant Articles: 
+- [Creating a Java Compiler Plugin](http://www.baeldung.com/java-build-compiler-plugin)

core-java-sun/pom.xml

@@ -0,0 +1,489 @@
+<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.baeldung</groupId>
+    <artifactId>core-java-sun</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <name>core-java-sun</name>
+
+    <dependencies>
+
+        <!-- utils -->
+        <dependency>
+            <groupId>net.sourceforge.collections</groupId>
+            <artifactId>collections-generic</artifactId>
+            <version>${collections-generic.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>${commons-collections4.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>${commons-io.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.decimal4j</groupId>
+            <artifactId>decimal4j</artifactId>
+            <version>${decimal4j.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.bouncycastle</groupId>
+            <artifactId>bcprov-jdk15on</artifactId>
+            <version>${bouncycastle.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.unix4j</groupId>
+            <artifactId>unix4j-command</artifactId>
+            <version>${unix4j.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.googlecode.grep4j</groupId>
+            <artifactId>grep4j</artifactId>
+            <version>${grep4j.version}</version>
+        </dependency>
+        <!-- web -->
+
+        <!-- marshalling -->
+
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+
+        <!-- logging -->
+        <dependency>
+            <groupId>log4j</groupId>
+            <artifactId>log4j</artifactId>
+            <version>1.2.17</version>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>${org.slf4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+            <version>${logback.version}</version>
+            <!-- <scope>runtime</scope> -->
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>jcl-over-slf4j</artifactId>
+            <version>${org.slf4j.version}</version>
+            <!-- <scope>runtime</scope> --> <!-- some spring dependencies need to compile against jcl -->
+        </dependency>
+        <dependency> <!-- needed to bridge to slf4j for projects that use the log4j APIs directly -->
+            <groupId>org.slf4j</groupId>
+            <artifactId>log4j-over-slf4j</artifactId>
+            <version>${org.slf4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+
+        <!-- test scoped -->
+
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-all</artifactId>
+            <version>1.3</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-core</artifactId>
+            <version>${org.hamcrest.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-library</artifactId>
+            <version>${org.hamcrest.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>${mockito.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.jayway.awaitility</groupId>
+            <artifactId>awaitility</artifactId>
+            <version>${avaitility.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>commons-codec</groupId>
+            <artifactId>commons-codec</artifactId>
+            <version>${commons-codec.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.javamoney</groupId>
+            <artifactId>moneta</artifactId>
+            <version>1.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.owasp.esapi</groupId>
+            <artifactId>esapi</artifactId>
+            <version>2.1.0.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.sun.messaging.mq</groupId>
+            <artifactId>fscontext</artifactId>
+            <version>${fscontext.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.codepoetics</groupId>
+            <artifactId>protonpack</artifactId>
+            <version>${protonpack.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>one.util</groupId>
+            <artifactId>streamex</artifactId>
+            <version>${streamex.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.vavr</groupId>
+            <artifactId>vavr</artifactId>
+            <version>${vavr.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-core</artifactId>
+            <version>1.19</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-generator-annprocess</artifactId>
+            <version>1.19</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-web</artifactId>
+            <version>4.3.4.RELEASE</version>
+        </dependency>
+        <dependency>
+            <groupId>com.sun</groupId>
+            <artifactId>tools</artifactId>
+            <version>1.8.0</version>
+            <scope>system</scope>
+            <systemPath>${java.home}/../lib/tools.jar</systemPath>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>core-java</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+
+        <plugins>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                </configuration>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <excludes>
+                        <exclude>**/*LiveTest.java</exclude>
+                        <exclude>**/*IntegrationTest.java</exclude>
+                        <exclude>**/*LongRunningUnitTest.java</exclude>
+                        <exclude>**/*ManualTest.java</exclude>
+                    </excludes>
+
+                </configuration>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-dependency-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>copy-dependencies</id>
+                        <phase>prepare-package</phase>
+                        <goals>
+                            <goal>copy-dependencies</goal>
+                        </goals>
+                        <configuration>
+                            <outputDirectory>${project.build.directory}/libs</outputDirectory>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <addClasspath>true</addClasspath>
+                            <classpathPrefix>libs/</classpathPrefix>
+                            <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
+                        </manifest>
+                    </archive>
+                </configuration>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                        <configuration>
+                            <archiveBaseDirectory>${project.basedir}</archiveBaseDirectory>
+                            <archive>
+                                <manifest>
+                                    <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
+                                </manifest>
+                            </archive>
+                            <descriptorRefs>
+                                <descriptorRef>jar-with-dependencies</descriptorRef>
+                            </descriptorRefs>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                        <configuration>
+                            <shadedArtifactAttached>true</shadedArtifactAttached>
+                            <transformers>
+                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                    <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
+                                </transformer>
+                            </transformers>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <plugin>
+                <groupId>com.jolira</groupId>
+                <artifactId>onejar-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <configuration>
+                            <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
+                            <attachToBuild>true</attachToBuild>
+                            <filename>${project.build.finalName}-onejar.${project.packaging}</filename>
+                        </configuration>
+                        <goals>
+                            <goal>one-jar</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>repackage</goal>
+                        </goals>
+                        <configuration>
+                            <classifier>spring-boot</classifier>
+                            <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+                <version>1.6.0</version>
+                <configuration>
+                    <executable>java</executable>
+                    <mainClass>com.baeldung.outofmemoryerror.OutOfMemoryGCLimitExceed</mainClass>
+                    <arguments>
+                        <argument>-Xmx300m</argument>
+                        <argument>-XX:+UseParallelGC</argument>
+                        <argument>-classpath</argument>
+                        <classpath />
+                        <argument>com.baeldung.outofmemoryerror.OutOfMemoryGCLimitExceed</argument>
+                    </arguments>
+                </configuration>
+            </plugin>
+
+
+        </plugins>
+
+    </build>
+
+    <profiles>
+        <profile>
+            <id>integration</id>
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-surefire-plugin</artifactId>
+                        <executions>
+                            <execution>
+                                <phase>integration-test</phase>
+                                <goals>
+                                    <goal>test</goal>
+                                </goals>
+                                <configuration>
+                                    <excludes>
+                                        <exclude>**/*ManualTest.java</exclude>
+                                    </excludes>
+                                    <includes>
+                                        <include>**/*IntegrationTest.java</include>
+                                    </includes>
+                                </configuration>
+                            </execution>
+                        </executions>
+                        <configuration>
+                            <systemPropertyVariables>
+                                <test.mime>json</test.mime>
+                            </systemPropertyVariables>
+                        </configuration>
+                    </plugin>
+                    <plugin>
+                        <groupId>org.codehaus.mojo</groupId>
+                        <artifactId>exec-maven-plugin</artifactId>
+
+                        <executions>
+                            <execution>
+                                <id>run-benchmarks</id>
+                                <!-- <phase>integration-test</phase> -->
+                                <phase>none</phase>
+                                <goals>
+                                    <goal>exec</goal>
+                                </goals>
+                                <configuration>
+                                    <classpathScope>test</classpathScope>
+                                    <executable>java</executable>
+                                    <arguments>
+                                        <argument>-classpath</argument>
+                                        <classpath />
+                                        <argument>org.openjdk.jmh.Main</argument>
+                                        <argument>.*</argument>
+                                    </arguments>
+                                </configuration>
+                            </execution>
+                        </executions>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+    </profiles>
+
+    <properties>
+        <!-- marshalling -->
+        <jackson.version>2.8.5</jackson.version>
+
+        <!-- logging -->
+        <org.slf4j.version>1.7.21</org.slf4j.version>
+        <logback.version>1.1.7</logback.version>
+
+        <!-- util -->
+        <guava.version>23.0</guava.version>
+        <commons-lang3.version>3.5</commons-lang3.version>
+        <bouncycastle.version>1.55</bouncycastle.version>
+        <commons-codec.version>1.10</commons-codec.version>
+        <commons-math3.version>3.6.1</commons-math3.version>
+        <decimal4j.version>1.0.3</decimal4j.version>
+        <commons-io.version>2.5</commons-io.version>
+        <commons-collections4.version>4.1</commons-collections4.version>
+        <collections-generic.version>4.01</collections-generic.version>
+        <unix4j.version>0.4</unix4j.version>
+        <grep4j.version>1.8.7</grep4j.version>
+        <lombok.version>1.16.12</lombok.version>
+        <fscontext.version>4.6-b01</fscontext.version>
+        <protonpack.version>1.13</protonpack.version>
+        <streamex.version>0.6.5</streamex.version>
+        <vavr.version>0.9.0</vavr.version>
+
+        <!-- testing -->
+        <org.hamcrest.version>1.3</org.hamcrest.version>
+        <junit.version>4.12</junit.version>
+        <mockito.version>2.8.9</mockito.version>
+        <assertj.version>3.6.1</assertj.version>
+        <avaitility.version>1.7.0</avaitility.version>
+
+        <!-- maven plugins -->
+        <maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
+        <maven-surefire-plugin.version>2.19.1</maven-surefire-plugin.version>
+    </properties>
+</project>

core-java-sun/src/main/java/com/baeldung/README.md

@@ -0,0 +1,2 @@
+### Relevant Articles:
+- [SHA-256 Hashing in Java](http://www.baeldung.com/sha-256-hashing-java)

core-java-sun/src/main/java/com/baeldung/javac/Positive.java

@@ -0,0 +1,9 @@
+package com.baeldung.javac;
+
+import java.lang.annotation.*;
+
+@Documented
+@Retention(RetentionPolicy.CLASS)
+@Target({ElementType.PARAMETER})
+public @interface Positive {
+}

core-java-sun/src/main/java/com/baeldung/javac/SampleJavacPlugin.java

@@ -0,0 +1,123 @@
+package com.baeldung.javac;
+
+import com.sun.source.tree.MethodTree;
+import com.sun.source.tree.VariableTree;
+import com.sun.source.util.*;
+import com.sun.tools.javac.api.BasicJavacTask;
+import com.sun.tools.javac.code.TypeTag;
+import com.sun.tools.javac.tree.JCTree;
+import com.sun.tools.javac.tree.TreeMaker;
+import com.sun.tools.javac.util.Context;
+import com.sun.tools.javac.util.Name;
+import com.sun.tools.javac.util.Names;
+
+import javax.tools.JavaCompiler;
+import java.util.*;
+import java.util.stream.Collectors;
+
+import static com.sun.tools.javac.util.List.nil;
+
+/**
+ * A {@link JavaCompiler javac} plugin which inserts {@code >= 0} checks into resulting {@code *.class} files
+ * for numeric method parameters marked by {@link Positive}
+ */
+public class SampleJavacPlugin implements Plugin {
+
+    public static final String NAME = "MyPlugin";
+
+    private static Set<String> TARGET_TYPES = new HashSet<>(Arrays.asList(
+        // Use only primitive types for simplicity
+        byte.class.getName(), short.class.getName(), char.class.getName(), 
+        int.class.getName(), long.class.getName(), float.class.getName(), double.class.getName()));
+
+    @Override
+    public String getName() {
+        return NAME;
+    }
+
+    @Override
+    public void init(JavacTask task, String... args) {
+        Context context = ((BasicJavacTask) task).getContext();
+        task.addTaskListener(new TaskListener() {
+            @Override
+            public void started(TaskEvent e) {
+            }
+
+            @Override
+            public void finished(TaskEvent e) {
+                if (e.getKind() != TaskEvent.Kind.PARSE) {
+                    return;
+                }
+                e.getCompilationUnit()
+                    .accept(new TreeScanner<Void, Void>() {
+                        @Override
+                        public Void visitMethod(MethodTree method, Void v) {
+                            List<VariableTree> parametersToInstrument = method.getParameters()
+                                .stream()
+                                .filter(SampleJavacPlugin.this::shouldInstrument)
+                                .collect(Collectors.toList());
+                            if (!parametersToInstrument.isEmpty()) {
+                                // There is a possible case that more than one argument is marked by @Positive,
+                                // as the checks are added to the method's body beginning, we process parameters RTL
+                                // to ensure correct order.
+                                Collections.reverse(parametersToInstrument);
+                                parametersToInstrument.forEach(p -> addCheck(method, p, context));
+                            }
+                            // There is a possible case that there is a nested class declared in a method's body,
+                            // hence, we want to proceed with method body AST as well.
+                            return super.visitMethod(method, v);
+                        }
+                    }, null);
+            }
+        });
+    }
+
+    private boolean shouldInstrument(VariableTree parameter) {
+        return TARGET_TYPES.contains(parameter.getType().toString())
+          && parameter.getModifiers().getAnnotations()
+            .stream()
+            .anyMatch(a -> Positive.class.getSimpleName().equals(a.getAnnotationType().toString()));
+    }
+
+    private void addCheck(MethodTree method, VariableTree parameter, Context context) {
+        JCTree.JCIf check = createCheck(parameter, context);
+        JCTree.JCBlock body = (JCTree.JCBlock) method.getBody();
+        body.stats = body.stats.prepend(check);
+    }
+
+    private static JCTree.JCIf createCheck(VariableTree parameter, Context context) {
+        TreeMaker factory = TreeMaker.instance(context);
+        Names symbolsTable = Names.instance(context);
+        
+        return factory.at(((JCTree) parameter).pos)
+          .If(factory.Parens(createIfCondition(factory, symbolsTable, parameter)),
+            createIfBlock(factory, symbolsTable, parameter),
+            null);
+    }
+
+    private static JCTree.JCBinary createIfCondition(TreeMaker factory, Names symbolsTable, VariableTree parameter) {
+        Name parameterId = symbolsTable.fromString(parameter.getName().toString());
+        return factory.Binary(JCTree.Tag.LE, 
+          factory.Ident(parameterId), 
+          factory.Literal(TypeTag.INT, 0));
+    }
+
+    private static JCTree.JCBlock createIfBlock(TreeMaker factory, Names symbolsTable, VariableTree parameter) {
+        String parameterName = parameter.getName().toString();
+        Name parameterId = symbolsTable.fromString(parameterName);
+        
+        String errorMessagePrefix = String.format("Argument '%s' of type %s is marked by @%s but got '", 
+          parameterName, parameter.getType(), Positive.class.getSimpleName());
+        String errorMessageSuffix = "' for it";
+        
+        return factory.Block(0, com.sun.tools.javac.util.List.of(
+          factory.Throw(
+            factory.NewClass(null, nil(), 
+              factory.Ident(symbolsTable.fromString(IllegalArgumentException.class.getSimpleName())),
+                com.sun.tools.javac.util.List.of(factory.Binary(JCTree.Tag.PLUS, 
+                  factory.Binary(JCTree.Tag.PLUS, factory.Literal(TypeTag.CLASS, errorMessagePrefix), 
+                    factory.Ident(parameterId)), 
+                    factory.Literal(TypeTag.CLASS, errorMessageSuffix))), null))));
+    }
+
+}

core-java-sun/src/main/resources/log4j.properties

@@ -0,0 +1,6 @@
+log4j.rootLogger=DEBUG, A1
+
+log4j.appender.A1=org.apache.log4j.ConsoleAppender
+
+log4j.appender.A1.layout=org.apache.log4j.PatternLayout
+log4j.appender.A1.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n

core-java-sun/src/test/java/com/baeldung/javac/SampleJavacPluginIntegrationTest.java

@@ -0,0 +1,42 @@
+package com.baeldung.javac;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class SampleJavacPluginIntegrationTest {
+
+    private static final String CLASS_TEMPLATE =
+            "package com.baeldung.javac;\n" +
+            "\n" +
+            "public class Test {\n" +
+            "    public static %1$s service(@Positive %1$s i) {\n" +
+            "        return i;\n" +
+            "    }\n" +
+            "}\n" +
+            "";
+
+    private TestCompiler compiler = new TestCompiler();
+    private TestRunner   runner   = new TestRunner();
+
+    @Test(expected = IllegalArgumentException.class)
+    public void givenInt_whenNegative_thenThrowsException() throws Throwable {
+        compileAndRun(double.class,-1);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void givenInt_whenZero_thenThrowsException() throws Throwable {
+        compileAndRun(int.class,0);
+    }
+
+    @Test
+    public void givenInt_whenPositive_thenSuccess() throws Throwable {
+        assertEquals(1, compileAndRun(int.class, 1));
+    }
+
+    private Object compileAndRun(Class<?> argumentType, Object argument) throws Throwable {
+        String qualifiedClassName = "com.baeldung.javac.Test";
+        byte[] byteCode = compiler.compile(qualifiedClassName, String.format(CLASS_TEMPLATE, argumentType.getName()));
+        return runner.run(byteCode, qualifiedClassName, "service", new Class[] {argumentType}, argument);
+    }
+}

core-java-sun/src/test/java/com/baeldung/javac/SimpleClassFile.java

@@ -0,0 +1,26 @@
+package com.baeldung.javac;
+
+import javax.tools.SimpleJavaFileObject;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.URI;
+
+/** Holds compiled byte code in a byte array */
+public class SimpleClassFile extends SimpleJavaFileObject {
+
+    private ByteArrayOutputStream out;
+
+    public SimpleClassFile(URI uri) {
+        super(uri, Kind.CLASS);
+    }
+
+    @Override
+    public OutputStream openOutputStream() throws IOException {
+        return out = new ByteArrayOutputStream();
+    }
+
+    public byte[] getCompiledBinaries() {
+        return out.toByteArray();
+    }
+}

core-java-sun/src/test/java/com/baeldung/javac/SimpleFileManager.java

@@ -0,0 +1,34 @@
+package com.baeldung.javac;
+
+import javax.tools.*;
+import java.net.URI;
+import java.util.ArrayList;
+import java.util.List;
+
+/** Adapts {@link SimpleClassFile} to the {@link JavaCompiler} */
+public class SimpleFileManager extends ForwardingJavaFileManager<StandardJavaFileManager> {
+
+    private final List<SimpleClassFile> compiled = new ArrayList<>();
+
+    public SimpleFileManager(StandardJavaFileManager delegate) {
+        super(delegate);
+    }
+
+    @Override
+    public JavaFileObject getJavaFileForOutput(Location location,
+                                               String className,
+                                               JavaFileObject.Kind kind,
+                                               FileObject sibling)
+    {
+        SimpleClassFile result = new SimpleClassFile(URI.create("string://" + className));
+        compiled.add(result);
+        return result;
+    }
+
+    /**
+     * @return  compiled binaries processed by the current class
+     */
+    public List<SimpleClassFile> getCompiled() {
+        return compiled;
+    }
+}

core-java-sun/src/test/java/com/baeldung/javac/SimpleSourceFile.java

@@ -0,0 +1,23 @@
+package com.baeldung.javac;
+
+import javax.tools.SimpleJavaFileObject;
+import java.net.URI;
+
+/** Exposes given test source to the compiler. */
+public class SimpleSourceFile extends SimpleJavaFileObject {
+
+    private final String content;
+
+    public SimpleSourceFile(String qualifiedClassName, String testSource) {
+        super(URI.create(String.format("file://%s%s",
+                                       qualifiedClassName.replaceAll("\\.", "/"),
+                                       Kind.SOURCE.extension)),
+              Kind.SOURCE);
+        content = testSource;
+    }
+
+    @Override
+    public CharSequence getCharContent(boolean ignoreEncodingErrors) {
+        return content;
+    }
+}

core-java-sun/src/test/java/com/baeldung/javac/TestCompiler.java

@@ -0,0 +1,35 @@
+package com.baeldung.javac;
+
+import javax.tools.JavaCompiler;
+import javax.tools.ToolProvider;
+import java.io.StringWriter;
+import java.util.ArrayList;
+import java.util.List;
+
+import static java.util.Arrays.asList;
+import static java.util.Collections.singletonList;
+
+public class TestCompiler {
+    public byte[] compile(String qualifiedClassName, String testSource) {
+        StringWriter output = new StringWriter();
+
+        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
+        SimpleFileManager fileManager = new SimpleFileManager(compiler.getStandardFileManager(
+                null,
+                null,
+                null
+        ));
+        List<SimpleSourceFile> compilationUnits = singletonList(new SimpleSourceFile(qualifiedClassName, testSource));
+        List<String> arguments = new ArrayList<>();
+        arguments.addAll(asList("-classpath", System.getProperty("java.class.path"),
+                                "-Xplugin:" + SampleJavacPlugin.NAME));
+        JavaCompiler.CompilationTask task = compiler.getTask(output,
+                                                             fileManager,
+                                                             null,
+                                                             arguments,
+                                                             null,
+                                                             compilationUnits);
+        task.call();
+        return fileManager.getCompiled().iterator().next().getCompiledBinaries();
+    }
+}

core-java-sun/src/test/java/com/baeldung/javac/TestRunner.java

@@ -0,0 +1,41 @@
+package com.baeldung.javac;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+public class TestRunner {
+
+    public Object run(byte[] byteCode,
+                      String qualifiedClassName,
+                      String methodName,
+                      Class<?>[] argumentTypes,
+                      Object... args)
+            throws Throwable
+    {
+        ClassLoader classLoader = new ClassLoader() {
+            @Override
+            protected Class<?> findClass(String name) throws ClassNotFoundException {
+                return defineClass(name, byteCode, 0, byteCode.length);
+            }
+        };
+        Class<?> clazz;
+        try {
+            clazz = classLoader.loadClass(qualifiedClassName);
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException("Can't load compiled test class", e);
+        }
+
+        Method method;
+        try {
+            method = clazz.getMethod(methodName, argumentTypes);
+        } catch (NoSuchMethodException e) {
+            throw new RuntimeException("Can't find the 'main()' method in the compiled test class", e);
+        }
+
+        try {
+            return method.invoke(null, args);
+        } catch (InvocationTargetException e) {
+            throw e.getCause();
+        }
+    }
+}

core-java/README.md

@@ -114,4 +114,10 @@
 - [StringBuilder and StringBuffer in Java](http://www.baeldung.com/java-string-builder-string-buffer)
 - [Number of Digits in an Integer in Java](http://www.baeldung.com/java-number-of-digits-in-int)
 - [Proxy, Decorator, Adapter and Bridge Patterns](http://www.baeldung.com/java-structural-design-patterns)
+- [Creating a Java Compiler Plugin](http://www.baeldung.com/java-build-compiler-plugin)
+- [A Guide to the Static Keyword in Java](http://www.baeldung.com/java-static)
+- [Initializing Arrays in Java](http://www.baeldung.com/java-initialize-array)
+- [Guide to Java String Pool](http://www.baeldung.com/java-string-pool)
+- [Copy a File with Java](http://www.baeldung.com/java-copy-file)
+- [Introduction to Creational Design Patterns](http://www.baeldung.com/creational-design-patterns)
 

core-java/pom.xml

@@ -181,11 +181,6 @@
             <version>2.1.0.1</version>
         </dependency>
 
-        <dependency>
-            <groupId>com.sun.messaging.mq</groupId>
-            <artifactId>fscontext</artifactId>
-            <version>${fscontext.version}</version>
-        </dependency>
         <dependency>
             <groupId>com.codepoetics</groupId>
             <artifactId>protonpack</artifactId>
@@ -249,7 +244,7 @@
                         <exclude>**/*LongRunningUnitTest.java</exclude>
                         <exclude>**/*ManualTest.java</exclude>
                     </excludes>
-                    <testFailureIgnore>true</testFailureIgnore>
+
                 </configuration>
             </plugin>
 
@@ -453,7 +448,7 @@
         <logback.version>1.1.7</logback.version>
 
         <!-- util -->
-        <guava.version>22.0</guava.version>
+        <guava.version>23.0</guava.version>
         <commons-lang3.version>3.5</commons-lang3.version>
         <bouncycastle.version>1.55</bouncycastle.version>
         <commons-codec.version>1.10</commons-codec.version>

core-java/src/main/java/com/baeldung/breakcontinue/BreakContinue.java

@@ -0,0 +1,138 @@
+package com.baeldung.breakcontinue;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+
+/**
+ * @author Santosh
+ *
+ */
+public class BreakContinue {
+
+    public static int unlabeledBreak() {
+        String searchName = "Wilson";
+        int counter = 0;
+        List<String> names = Arrays.asList("John", "Peter", "Robert", "Wilson", "Anthony", "Donald", "Richard");
+
+        for (String name : names) {
+            counter++;
+            if (name.equalsIgnoreCase(searchName)) {
+                break;
+            }
+        }
+
+        return counter;
+    }
+
+    public static int unlabeledBreakNestedLoops() {
+        String searchName = "Wilson";
+        int counter = 0;
+        Map<String, List<String>> nameMap = new HashMap<>();
+        nameMap.put("Grade1", Arrays.asList("John", "Peter", "Robert", "Wilson"));
+        nameMap.put("Grade2", Arrays.asList("Anthony", "Donald", "Richard", "Arnold"));
+        nameMap.put("Grade3", Arrays.asList("Wilson", "Michael", "Stephen", "Ryan"));
+
+        Iterator<Entry<String, List<String>>> iterator = nameMap.entrySet()
+            .iterator();
+        Entry<String, List<String>> entry = null;
+        List<String> names = null;
+        while (iterator.hasNext()) {
+            entry = iterator.next();
+            names = entry.getValue();
+            for (String name : names) {
+                if (name.equalsIgnoreCase(searchName)) {
+                    counter++;
+                    break;
+                }
+            }
+        }
+
+        return counter;
+    }
+
+    public static int labeledBreak() {
+        String searchName = "Wilson";
+        int counter = 0;
+        Map<String, List<String>> nameMap = new HashMap<>();
+        nameMap.put("Grade1", Arrays.asList("John", "Peter", "Robert", "Wilson"));
+        nameMap.put("Grade2", Arrays.asList("Anthony", "Donald", "Richard", "Arnold"));
+        nameMap.put("Grade3", Arrays.asList("Wilson", "Michael", "Stephen", "Ryan"));
+
+        Iterator<Entry<String, List<String>>> iterator = nameMap.entrySet()
+            .iterator();
+        Entry<String, List<String>> entry = null;
+        List<String> names = null;
+        compare: 
+        while (iterator.hasNext()) {
+            entry = iterator.next();
+            names = entry.getValue();
+            for (String name : names) {
+                if (name.equalsIgnoreCase(searchName)) {
+                    counter++;
+                    break compare;
+                }
+            }
+        }
+
+        return counter;
+    }
+
+    public static int unlabeledContinue() {
+        String searchName = "Wilson";
+        int counter = 0;
+        Map<String, List<String>> nameMap = new HashMap<>();
+        nameMap.put("Grade1", Arrays.asList("John", "Wilson", "Robert", "Wilson"));
+        nameMap.put("Grade2", Arrays.asList("Anthony", "Donald", "Wilson", "Arnold"));
+        nameMap.put("Grade3", Arrays.asList("Wilson", "Michael", "Wilson", "Ryan"));
+
+        Iterator<Entry<String, List<String>>> iterator = nameMap.entrySet()
+            .iterator();
+        Entry<String, List<String>> entry = null;
+        List<String> names = null;
+        while (iterator.hasNext()) {
+            entry = iterator.next();
+            names = entry.getValue();
+            for (String name : names) {
+                if (!name.equalsIgnoreCase(searchName)) {
+                    continue;
+                }
+
+                counter++;
+            }
+        }
+
+        return counter;
+    }
+
+    public static int labeledContinue() {
+        String searchName = "Wilson";
+        int counter = 0;
+        Map<String, List<String>> nameMap = new HashMap<>();
+        nameMap.put("Grade1", Arrays.asList("John", "Wilson", "Robert", "Wilson"));
+        nameMap.put("Grade2", Arrays.asList("Anthony", "Donald", "Wilson", "Arnold"));
+        nameMap.put("Grade3", Arrays.asList("Wilson", "Michael", "Wilson", "Ryan"));
+
+        Iterator<Entry<String, List<String>>> iterator = nameMap.entrySet()
+            .iterator();
+        Entry<String, List<String>> entry = null;
+        List<String> names = null;
+        compare: 
+        while (iterator.hasNext()) {
+            entry = iterator.next();
+            names = entry.getValue();
+            for (String name : names) {
+                if (name.equalsIgnoreCase(searchName)) {
+                    counter++;
+                    continue compare;
+                }
+            }
+        }
+
+        return counter;
+    }
+
+}

core-java/src/main/java/com/baeldung/comparable/Player.java

@@ -0,0 +1,51 @@
+package com.baeldung.comparable;
+
+public class Player implements Comparable<Player> {
+
+    private int ranking;
+
+    private String name;
+
+    private int age;
+
+    public Player(int ranking, String name, int age) {
+        this.ranking = ranking;
+        this.name = name;
+        this.age = age;
+    }
+
+    public int getRanking() {
+        return ranking;
+    }
+
+    public void setRanking(int ranking) {
+        this.ranking = ranking;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    @Override
+    public String toString() {
+        return this.name;
+    }
+
+    @Override
+    public int compareTo(Player otherPlayer) {
+        return (this.getRanking() - otherPlayer.getRanking());
+    }
+
+}

core-java/src/main/java/com/baeldung/comparable/PlayerSorter.java

@@ -0,0 +1,25 @@
+package com.baeldung.comparable;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class PlayerSorter {
+
+    public static void main(String[] args) {
+
+        List<Player> footballTeam = new ArrayList<Player>();
+        Player player1 = new Player(59, "John", 20);
+        Player player2 = new Player(67, "Roger", 22);
+        Player player3 = new Player(45, "Steven", 24);
+        footballTeam.add(player1);
+        footballTeam.add(player2);
+        footballTeam.add(player3);
+
+        System.out.println("Before Sorting : " + footballTeam);
+        Collections.sort(footballTeam);
+        System.out.println("After Sorting : " + footballTeam);
+
+    }
+
+}

core-java/src/main/java/com/baeldung/comparator/Player.java

@@ -0,0 +1,46 @@
+package com.baeldung.comparator;
+
+public class Player {
+
+    private int ranking;
+
+    private String name;
+
+    private int age;
+
+    public Player(int ranking, String name, int age) {
+        this.ranking = ranking;
+        this.name = name;
+        this.age = age;
+    }
+
+    public int getRanking() {
+        return ranking;
+    }
+
+    public void setRanking(int ranking) {
+        this.ranking = ranking;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    @Override
+    public String toString() {
+        return this.name;
+    }
+
+}

core-java/src/main/java/com/baeldung/comparator/PlayerAgeComparator.java

@@ -0,0 +1,12 @@
+package com.baeldung.comparator;
+
+import java.util.Comparator;
+
+public class PlayerAgeComparator implements Comparator<Player> {
+
+    @Override
+    public int compare(Player firstPlayer, Player secondPlayer) {
+       return (firstPlayer.getAge() - secondPlayer.getAge());
+    }
+
+}

core-java/src/main/java/com/baeldung/comparator/PlayerAgeSorter.java

@@ -0,0 +1,27 @@
+package com.baeldung.comparator;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class PlayerAgeSorter {
+
+    public static void main(String[] args) {
+        
+        List<Player> footballTeam = new ArrayList<Player>();
+        Player player1 = new Player(59, "John", 22);
+        Player player2 = new Player(67, "Roger", 20);
+        Player player3 = new Player(45, "Steven", 24);
+        footballTeam.add(player1);
+        footballTeam.add(player2);
+        footballTeam.add(player3);
+        
+        System.out.println("Before Sorting : " + footballTeam);
+        //Instance of PlayerAgeComparator
+        PlayerAgeComparator playerComparator = new PlayerAgeComparator();
+        Collections.sort(footballTeam, playerComparator);
+        System.out.println("After Sorting by age : " + footballTeam);
+        
+    }
+
+}

core-java/src/main/java/com/baeldung/comparator/PlayerRankingComparator.java

@@ -0,0 +1,12 @@
+package com.baeldung.comparator;
+
+import java.util.Comparator;
+
+public class PlayerRankingComparator implements Comparator<Player> {
+
+    @Override
+    public int compare(Player firstPlayer, Player secondPlayer) {
+       return (firstPlayer.getRanking() - secondPlayer.getRanking());
+    }
+
+}

core-java/src/main/java/com/baeldung/comparator/PlayerRankingSorter.java

@@ -0,0 +1,27 @@
+package com.baeldung.comparator;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class PlayerRankingSorter {
+
+    public static void main(String[] args) {
+        
+        List<Player> footballTeam = new ArrayList<Player>();
+        Player player1 = new Player(59, "John", 22);
+        Player player2 = new Player(67, "Roger", 20);
+        Player player3 = new Player(45, "Steven", 40);
+        footballTeam.add(player1);
+        footballTeam.add(player2);
+        footballTeam.add(player3);
+        
+        System.out.println("Before Sorting : " + footballTeam);
+        //Instance of PlayerRankingComparator
+        PlayerRankingComparator playerComparator = new PlayerRankingComparator();
+        Collections.sort(footballTeam, playerComparator);
+        System.out.println("After Sorting by ranking : " + footballTeam);
+        
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/abstractfactory/AbstractFactory.java

@@ -0,0 +1,6 @@
+package com.baeldung.designpatterns.creational.abstractfactory;
+
+public interface AbstractFactory {
+    Animal getAnimal(String toyType) ;
+    Color getColor(String colorType);
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/abstractfactory/AbstractPatternDriver.java

@@ -0,0 +1,18 @@
+package com.baeldung.designpatterns.creational.abstractfactory;
+
+public class AbstractPatternDriver {
+    public static void main(String[] args) {
+        AbstractFactory abstractFactory;
+        
+        //creating a brown toy dog
+        abstractFactory = FactoryProvider.getFactory("Toy");
+        Animal toy = abstractFactory.getAnimal("Dog");
+        
+        abstractFactory = FactoryProvider.getFactory("Color");
+        Color color = abstractFactory.getColor("Brown");
+        
+        String result = "A " + toy.getType() + " with " + color.getColor() + " color " + toy.makeSound();
+        
+        System.out.println(result);
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/abstractfactory/Animal.java

@@ -0,0 +1,6 @@
+package com.baeldung.designpatterns.creational.abstractfactory;
+
+public interface Animal {
+    String getType();
+    String makeSound();
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/abstractfactory/AnimalFactory.java

@@ -0,0 +1,21 @@
+package com.baeldung.designpatterns.creational.abstractfactory;
+
+public class AnimalFactory implements AbstractFactory {
+
+    @Override
+    public Animal getAnimal(String animalType) {
+        if ("Dog".equalsIgnoreCase(animalType)) {
+            return new Dog();
+        } else if ("Duck".equalsIgnoreCase(animalType)) {
+            return new Duck();
+        }
+
+        return null;
+    }
+
+    @Override
+    public Color getColor(String color) {
+        throw new UnsupportedOperationException();
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/abstractfactory/Brown.java

@@ -0,0 +1,10 @@
+package com.baeldung.designpatterns.creational.abstractfactory;
+
+public class Brown implements Color {
+
+    @Override
+    public String getColor() {
+        return "brown";
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/abstractfactory/Color.java

@@ -0,0 +1,5 @@
+package com.baeldung.designpatterns.creational.abstractfactory;
+
+public interface Color {
+    String getColor();
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/abstractfactory/ColorFactory.java

@@ -0,0 +1,21 @@
+package com.baeldung.designpatterns.creational.abstractfactory;
+
+public class ColorFactory implements AbstractFactory {
+
+    @Override
+    public Color getColor(String colorType) {
+        if ("Brown".equalsIgnoreCase(colorType)) {
+            return new Brown();
+        } else if ("White".equalsIgnoreCase(colorType)) {
+            return new White();
+        }
+
+        return null;
+    }
+
+    @Override
+    public Animal getAnimal(String toyType) {
+        throw new UnsupportedOperationException();
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/abstractfactory/Dog.java

@@ -0,0 +1,15 @@
+package com.baeldung.designpatterns.creational.abstractfactory;
+
+public class Dog implements Animal {
+
+    @Override
+    public String getType() {
+        return "Dog";
+    }
+
+    @Override
+    public String makeSound() {
+        return "Barks";
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/abstractfactory/Duck.java

@@ -0,0 +1,15 @@
+package com.baeldung.designpatterns.creational.abstractfactory;
+
+public class Duck implements Animal {
+
+    @Override
+    public String getType() {
+        return "Duck";
+    }
+
+    @Override
+    public String makeSound() {
+        return "Squeks";
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/abstractfactory/FactoryProvider.java

@@ -0,0 +1,15 @@
+package com.baeldung.designpatterns.creational.abstractfactory;
+
+public class FactoryProvider {
+    public static AbstractFactory getFactory(String choice){
+        
+        if("Toy".equalsIgnoreCase(choice)){
+            return new AnimalFactory();
+        }
+        else if("Color".equalsIgnoreCase(choice)){
+            return new ColorFactory();
+        }
+        
+        return null;
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/abstractfactory/White.java

@@ -0,0 +1,10 @@
+package com.baeldung.designpatterns.creational.abstractfactory;
+
+public class White implements Color {
+
+    @Override
+    public String getColor() {
+        return "White";
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/builder/BankAccount.java

@@ -0,0 +1,64 @@
+package com.baeldung.designpatterns.creational.builder;
+
+public class BankAccount {
+    private String name;
+    private String accountNumber;
+    private String email;
+    private boolean newsletter;
+
+    //The constructor that takes a builder from which it will create object
+    //the access to this is only provided to builder
+    private BankAccount(BankAccountBuilder builder) {
+        this.name = builder.name;
+        this.accountNumber = builder.accountNumber;
+        this.email = builder.email;
+        this.newsletter = builder.newsletter;
+    }
+    
+    public static class BankAccountBuilder {
+        private String name;
+        private String accountNumber;
+        private String email;
+        private boolean newsletter;
+        
+        //All Mandatory parameters goes with this constructor
+        public BankAccountBuilder(String name, String accountNumber) {
+            this.name = name;
+            this.accountNumber = accountNumber;
+        }
+
+        //setters for optional parameters which returns this same builder
+        //to support fluent design
+        public BankAccountBuilder withEmail(String email) {
+            this.email = email;
+            return this;
+        }
+
+        public BankAccountBuilder wantNewsletter(boolean newsletter) {
+            this.newsletter = newsletter;
+            return this;
+        }
+        
+        //the actual build method that prepares and returns a BankAccount object
+        public BankAccount build() {
+            return new BankAccount(this);
+        }
+    }
+
+    //getters
+    public String getName() {
+        return name;
+    }
+
+    public String getAccountNumber() {
+        return accountNumber;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public boolean isNewsletter() {
+        return newsletter;
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/builder/BuilderPatternDriver.java

@@ -0,0 +1,16 @@
+package com.baeldung.designpatterns.creational.builder;
+
+public class BuilderPatternDriver {
+    public static void main(String[] args) {
+        BankAccount newAccount = new BankAccount
+          .BankAccountBuilder("Jon", "22738022275")
+          .withEmail("jon@example.com")
+          .wantNewsletter(true)
+          .build();
+
+        System.out.println("Name: " + newAccount.getName());
+        System.out.println("AccountNumber:" + newAccount.getAccountNumber());
+        System.out.println("Email: " + newAccount.getEmail());
+        System.out.println("Want News letter?: " + newAccount.isNewsletter());
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/factory/FactoryDriver.java

@@ -0,0 +1,16 @@
+package com.baeldung.designpatterns.creational.factory;
+
+public class FactoryDriver {
+    public static void main(String[] args) {
+        Polygon p;
+        PolygonFactory factory = new PolygonFactory();
+        
+        //get the shape which has 4 sides
+        p = factory.getPolygon(4);
+        System.out.println("The shape with 4 sides is a " + p.getType());
+        
+        //get the shape which has 4 sides
+        p = factory.getPolygon(8);
+        System.out.println("The shape with 8 sides is a " + p.getType());
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/factory/Heptagon.java

@@ -0,0 +1,10 @@
+package com.baeldung.designpatterns.creational.factory;
+
+public class Heptagon implements Polygon {
+
+    @Override
+    public String getType() {
+        return "Heptagon";
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/factory/Octagon.java

@@ -0,0 +1,10 @@
+package com.baeldung.designpatterns.creational.factory;
+
+public class Octagon implements Polygon {
+
+    @Override
+    public String getType() {
+        return "Octagon";
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/factory/Pentagon.java

@@ -0,0 +1,10 @@
+package com.baeldung.designpatterns.creational.factory;
+
+public class Pentagon implements Polygon {
+
+    @Override
+    public String getType() {
+        return "Pentagon";
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/factory/Polygon.java

@@ -0,0 +1,5 @@
+package com.baeldung.designpatterns.creational.factory;
+
+public interface Polygon {
+    String getType();
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/factory/PolygonFactory.java

@@ -0,0 +1,22 @@
+package com.baeldung.designpatterns.creational.factory;
+
+public class PolygonFactory {
+    public Polygon getPolygon(int numberOfSides) {
+        if(numberOfSides == 3) {
+            return new Triangle();
+        }
+        if(numberOfSides == 4) {
+            return new Square();
+        }
+        if(numberOfSides == 5) {
+            return new Pentagon();
+        }
+        if(numberOfSides == 7) {
+            return new Heptagon();
+        }
+        else if(numberOfSides == 8) {
+            return new Octagon();
+        }
+        return null;
+    }
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/factory/Square.java

@@ -0,0 +1,10 @@
+package com.baeldung.designpatterns.creational.factory;
+
+public class Square implements Polygon {
+
+    @Override
+    public String getType() {
+        return "Square";
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/factory/Triangle.java

@@ -0,0 +1,10 @@
+package com.baeldung.designpatterns.creational.factory;
+
+public class Triangle implements Polygon {
+
+    @Override
+    public String getType() {
+        return "Triangle";
+    }
+
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/singleton/Singleton.java

@@ -0,0 +1,13 @@
+package com.baeldung.designpatterns.creational.singleton;
+
+public class Singleton  {    
+    private Singleton() {}
+    
+    private static class SingletonHolder {    
+        public static final Singleton instance = new Singleton();
+    }    
+
+    public static Singleton getInstance() {    
+        return SingletonHolder.instance;    
+    }    
+}

core-java/src/main/java/com/baeldung/designpatterns/creational/singleton/SingletonDriver.java

@@ -0,0 +1,8 @@
+package com.baeldung.designpatterns.creational.singleton;
+
+public class SingletonDriver {
+    public static void main(String[] args) {
+        Singleton instance = Singleton.getInstance();
+        System.out.println(instance.toString());
+    }
+}

core-java/src/main/java/com/baeldung/loops/LoopsInJava.java

@@ -0,0 +1,43 @@
+package com.baeldung.loops;
+
+public class LoopsInJava {
+
+    public int[] simple_for_loop() {
+        int[] arr = new int[5];
+        for (int i = 0; i < 5; i++) {
+            arr[i] = i;
+            System.out.println("Simple for loop: i - " + i);
+        }
+        return arr;
+    }
+
+    public int[] enhanced_for_each_loop() {
+        int[] intArr = { 0, 1, 2, 3, 4 };
+        int[] arr = new int[5];
+        for (int num : intArr) {
+            arr[num] = num;
+            System.out.println("Enhanced for-each loop: i - " + num);
+        }
+        return arr;
+    }
+
+    public int[] while_loop() {
+        int i = 0;
+        int[] arr = new int[5];
+        while (i < 5) {
+            arr[i] = i;
+            System.out.println("While loop: i - " + i++);
+        }
+        return arr;
+    }
+
+    public int[] do_while_loop() {
+        int i = 0;
+        int[] arr = new int[5];
+        do {
+            arr[i] = i;
+            System.out.println("Do-While loop: i - " + i++);
+        } while (i < 5);
+        return arr;
+    }
+}