Merge branch 'master' of https://github.com/eugenp/tutorials into BAEL-15393

algorithms-miscellaneous-3/src/main/java/com/baeldung/algorithms/bucketsort/IntegerBucketSorter.java

@@ -0,0 +1,70 @@
+package com.baeldung.bucketsort;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+
+public class IntegerBucketSorter implements Sorter<Integer> {
+
+    private final Comparator<Integer> comparator;
+
+    public IntegerBucketSorter(Comparator<Integer> comparator) {
+        this.comparator = comparator;
+    }
+
+    public IntegerBucketSorter() {
+        comparator = Comparator.naturalOrder();
+    }
+
+    public List<Integer> sort(List<Integer> arrayToSort) {
+
+        List<List<Integer>> buckets = splitIntoUnsortedBuckets(arrayToSort);
+
+        for(List<Integer> bucket  : buckets){
+            bucket.sort(comparator);
+        }
+
+        return concatenateSortedBuckets(buckets);
+    }
+
+    private List<Integer> concatenateSortedBuckets(List<List<Integer>> buckets){
+        List<Integer> sortedArray = new ArrayList<>();
+        int index = 0;
+        for(List<Integer> bucket : buckets){
+            for(int number : bucket){
+                sortedArray.add(index++, number);
+            }
+        }
+        return sortedArray;
+    }
+
+    private List<List<Integer>> splitIntoUnsortedBuckets(List<Integer> initialList){
+
+        final int[] codes = createHashes(initialList);
+
+        List<List<Integer>> buckets = new ArrayList<>(codes[1]);
+        for(int i = 0; i < codes[1]; i++) buckets.add(new ArrayList<>());
+
+        //distribute the data
+        for (int i : initialList) {
+            buckets.get(hash(i, codes)).add(i);
+        }
+        return buckets;
+
+    }
+
+    private int[] createHashes(List<Integer> input){
+        int m = input.get(0);
+        for (int i = 1; i < input.size(); i++) {
+            if (m < input.get(i)) {
+                m = input.get(i);
+            }
+        }
+        return new int[]{m, (int) Math.sqrt(input.size())};
+    }
+
+    private static int hash(int i, int[] code) {
+        return (int) ((double) i / code[0] * (code[1] - 1));
+    }
+
+}

algorithms-miscellaneous-3/src/main/java/com/baeldung/algorithms/bucketsort/Sorter.java

@@ -0,0 +1,8 @@
+package com.baeldung.bucketsort;
+
+import java.util.List;
+
+public interface Sorter<T> {
+
+    List<T> sort(List<T> arrayToSort);
+}

algorithms-miscellaneous-3/src/test/java/com/baeldung/algorithms/bucketsort/IntegerBucketSorterUnitTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.bucketsort;
+
+import com.baeldung.bucketsort.IntegerBucketSorter;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+
+public class IntegerBucketSorterUnitTest {
+
+    private IntegerBucketSorter sorter;
+
+    @Before
+    public void setUp() throws Exception {
+        sorter = new IntegerBucketSorter();
+    }
+
+    @Test
+    public void givenUnsortedList_whenSortedUsingBucketSorter_checkSortingCorrect() {
+
+        List<Integer> unsorted = Arrays.asList(80,50,60,30,20,10,70,0,40,500,600,602,200,15);
+        List<Integer> expected = Arrays.asList(0,10,15,20,30,40,50,60,70,80,200,500,600,602);
+
+        List<Integer> actual = sorter.sort(unsorted);
+
+        assertEquals(expected, actual);
+
+
+    }
+}

core-groovy-2/pom.xml

@@ -48,6 +48,11 @@
             <version>${spock-core.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.github.groovy-wslite</groupId>
+            <artifactId>groovy-wslite</artifactId>
+            <version>${groovy-wslite.version}</version>
+        </dependency>
     </dependencies>
 
     <build>
@@ -175,6 +180,7 @@
         <junit.platform.version>1.0.0</junit.platform.version>
         <hsqldb.version>2.4.0</hsqldb.version>
         <spock-core.version>1.1-groovy-2.4</spock-core.version>
+        <groovy-wslite.version>1.1.3</groovy-wslite.version>        
         <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
         <logback.version>1.2.3</logback.version>
         <groovy.version>2.5.7</groovy.version>

core-groovy-2/src/test/groovy/com/baeldung/webservice/WebserviceUnitTest.groovy

@@ -0,0 +1,152 @@
+package com.baeldung.webservice
+
+import groovy.json.JsonSlurper
+import wslite.rest.ContentType
+import wslite.rest.RESTClient
+import wslite.rest.RESTClientException
+import wslite.soap.SOAPClient
+import wslite.soap.SOAPMessageBuilder
+import wslite.http.auth.HTTPBasicAuthorization
+import org.junit.Test
+
+class WebserviceUnitTest extends GroovyTestCase {
+
+    JsonSlurper jsonSlurper = new JsonSlurper()
+
+    static RESTClient client = new RESTClient("https://postman-echo.com")
+    
+    static {
+        client.defaultAcceptHeader = ContentType.JSON
+        client.httpClient.sslTrustAllCerts = true
+    }
+
+    void test_whenSendingGet_thenRespose200() {
+        def postmanGet = new URL('https://postman-echo.com/get')
+        def getConnection = postmanGet.openConnection()
+        getConnection.requestMethod = 'GET'
+        assert getConnection.responseCode == 200
+        if (getConnection.responseCode == 200) {
+            assert jsonSlurper.parseText(getConnection.content.text)?.headers?.host == "postman-echo.com"
+        }
+    }
+
+    void test_whenSendingPost_thenRespose200() {
+        def postmanPost = new URL('https://postman-echo.com/post')
+        def query = "q=This is post request form parameter."
+        def postConnection = postmanPost.openConnection()
+        postConnection.requestMethod = 'POST'
+        assert postConnection.responseCode == 200
+    }
+    
+    void test_whenSendingPostWithParams_thenRespose200() {
+        def postmanPost = new URL('https://postman-echo.com/post')
+        def form = "param1=This is request parameter."
+        def postConnection = postmanPost.openConnection()
+        postConnection.requestMethod = 'POST'
+        postConnection.doOutput = true
+        def text
+        postConnection.with {
+            outputStream.withWriter { outputStreamWriter ->
+                outputStreamWriter << form
+            }
+            text = content.text
+        }
+        assert postConnection.responseCode == 200
+        assert jsonSlurper.parseText(text)?.json.param1 == "This is request parameter."
+    }
+    
+    void test_whenReadingRSS_thenReceiveFeed() {
+        def rssFeed = new XmlParser().parse("https://news.google.com/rss?hl=en-US&gl=US&ceid=US:en")
+        def stories = []
+        (0..4).each {
+            def item = rssFeed.channel.item.get(it)
+            stories << item.title.text()
+        }
+        assert stories.size() == 5
+    }
+
+    void test_whenReadingAtom_thenReceiveFeed() {
+        def atomFeed = new XmlParser().parse("https://news.google.com/atom?hl=en-US&gl=US&ceid=US:en")
+        def stories = []
+        (0..4).each {
+            def entry = atomFeed.entry.get(it)
+            stories << entry.title.text()
+        }
+        assert stories.size() == 5
+    }
+    
+    void test_whenConsumingSoap_thenReceiveResponse() {
+        def url = "http://www.dataaccess.com/webservicesserver/numberconversion.wso"
+        def soapClient = new SOAPClient(url)
+        def message = new SOAPMessageBuilder().build({
+            body {
+                NumberToWords(xmlns: "http://www.dataaccess.com/webservicesserver/") {
+                    ubiNum(1234)
+                }
+            }
+        })
+        def response = soapClient.send(message.toString());
+        def words = response.NumberToWordsResponse
+        assert words == "one thousand two hundred and thirty four "
+    }
+
+    void test_whenConsumingRestGet_thenReceiveResponse() {
+        def path = "/get"
+        def response
+        try {
+            response = client.get(path: path)
+            assert response.statusCode == 200
+            assert response.json?.headers?.host == "postman-echo.com"
+        } catch (RESTClientException e) {
+            assert e?.response?.statusCode != 200
+        }
+    }
+
+    void test_whenConsumingRestPost_thenReceiveResponse() {
+        def path = "/post"
+        def params = ["foo":1,"bar":2]
+        def response
+        try {
+            response = client.post(path: path) {
+                type ContentType.JSON
+                json params
+            }
+            assert response.json?.data == params
+        } catch (RESTClientException e) {
+            e.printStackTrace()
+            assert e?.response?.statusCode != 200
+        }
+    }
+
+    void test_whenBasicAuthentication_thenReceive200() {
+        def path = "/basic-auth"
+        def response
+        try {
+            client.authorization = new HTTPBasicAuthorization("postman", "password")
+            response = client.get(path: path)
+            assert response.statusCode == 200
+            assert response.json?.authenticated == true
+        } catch (RESTClientException e) {
+            e.printStackTrace()
+            assert e?.response?.statusCode != 200
+        }
+    }
+
+    void test_whenOAuth_thenReceive200() {
+        RESTClient oAuthClient = new RESTClient("https://postman-echo.com")
+        oAuthClient.defaultAcceptHeader = ContentType.JSON
+        oAuthClient.httpClient.sslTrustAllCerts = true
+
+        def path = "/oauth1"
+        def params = [oauth_consumer_key: "RKCGzna7bv9YD57c", oauth_signature_method: "HMAC-SHA1", oauth_timestamp:1567089944, oauth_nonce: "URT7v4", oauth_version: 1.0, oauth_signature: 'RGgR/ktDmclkM0ISWaFzebtlO0A=']
+        def response
+        try {
+            response = oAuthClient.get(path: path, query: params)
+            assert response.statusCode == 200
+            assert response.statusMessage == "OK"
+            assert response.json.status == "pass"
+        } catch (RESTClientException e) {
+            assert e?.response?.statusCode != 200
+        }
+    }
+}

core-java-modules/core-java-collections-array-list/src/main/java/com/baeldung/java/list/RemoveFromList.java

@@ -0,0 +1,40 @@
+package com.baeldung.java.list;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+public class RemoveFromList {
+
+        public static void main(String[] args) {
+                List<String> sports = new ArrayList<>();
+                sports.add("Football");
+                sports.add("Basketball");
+                sports.add("Baseball");
+                sports.add("Boxing");
+                sports.add("Cycling");
+
+                System.out.println("List before removing:  " + sports);
+
+                // Remove with index
+                sports.remove(1);
+
+                // Remove with an element
+                sports.remove("Baseball");
+
+                // Iterator remove method
+                Iterator<String> iterator = sports.iterator();
+                while (iterator.hasNext()) {
+                        if (iterator.next().equals("Boxing")) {
+                                iterator.remove();
+                                break;
+                        }
+                }
+
+                // ArrayList removeIf method (Java 8)
+                sports.removeIf(p -> p.equals("Cycling"));
+
+                System.out.println("List after removing:  " + sports);
+        }
+
+}

core-java-modules/core-java-io-2/src/test/java/com/baeldung/filereader/FileReaderExampleUnitTest.java

@@ -17,15 +17,9 @@ public class FileReaderExampleUnitTest {
     public void givenFileReader_whenReadAllCharacters_thenReturnsContent() throws IOException {
         String expectedText = "Hello, World!";
         File file = new File(FILE_PATH);
-        FileReader fileReader = null;
-        try {
-            fileReader = new FileReader(file);
+        try (FileReader fileReader = new FileReader(file)) {
             String content = FileReaderExample.readAllCharactersOneByOne(fileReader);
             Assert.assertEquals(expectedText, content);
-        } finally {
-            if (fileReader != null) {
-                fileReader.close();
-            }
         }
     }
 
@@ -33,15 +27,9 @@ public class FileReaderExampleUnitTest {
     public void givenFileReader_whenReadMultipleCharacters_thenReturnsContent() throws IOException {
         String expectedText = "Hello";
         File file = new File(FILE_PATH);
-        FileReader fileReader = null;
-        try {
-            fileReader = new FileReader(file);
+        try (FileReader fileReader = new FileReader(file)) {
             String content = FileReaderExample.readMultipleCharacters(fileReader, 5);
             Assert.assertEquals(expectedText, content);
-        } finally {
-            if (fileReader != null) {
-                fileReader.close();
-            }
         }
     }
 

core-java-modules/core-java-io/pom.xml

@@ -207,6 +207,21 @@
                     <target>${maven.compiler.target}</target>
                 </configuration>
             </plugin>
+            
+            <plugin>
+                <!-- Build an executable JAR -->
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>${maven-jar-plugin.version}</version>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <addClasspath>true</addClasspath>
+                            <mainClass>com.baeldung.resource.MyResourceLoader</mainClass>
+                        </manifest>
+                    </archive>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
 
@@ -274,6 +289,8 @@
         <!-- Mime Type Libraries -->
         <tika.version>1.18</tika.version>
         <jmime-magic.version>0.1.5</jmime-magic.version>
+        <maven-jar-plugin.version>3.1.0</maven-jar-plugin.version>
+
     </properties>
 
 </project>

core-java-modules/core-java-io/src/main/java/com/baeldung/resource/MyResourceLoader.java

@@ -0,0 +1,42 @@
+package com.baeldung.resource;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.stream.Collectors;
+
+public class MyResourceLoader {
+
+    private void loadFileWithReader() throws IOException {
+
+        try (FileReader fileReader = new FileReader("src/main/resources/input.txt");
+             BufferedReader reader = new BufferedReader(fileReader)) {
+            String contents = reader.lines()
+                .collect(Collectors.joining(System.lineSeparator()));
+            System.out.println(contents);
+        }
+
+    }
+
+    private void loadFileAsResource() throws IOException {
+
+        try (InputStream inputStream = getClass().getResourceAsStream("/input.txt");
+             BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream))) {
+            String contents = reader.lines()
+                .collect(Collectors.joining(System.lineSeparator()));
+            System.out.println(contents);
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+
+        MyResourceLoader resourceLoader = new MyResourceLoader();
+
+        resourceLoader.loadFileAsResource();
+        resourceLoader.loadFileWithReader();
+
+    }
+
+}

core-java-modules/core-java-lang-oop-2/src/main/java/com/baeldung/copyconstructor/Employee.java

@@ -0,0 +1,30 @@
+package com.baeldung.copyconstructor;
+
+import java.util.Date;
+
+public class Employee {
+
+    protected int id;
+    protected String name;
+    protected Date startDate;
+
+    public Employee(int id, String name, Date startDate) {
+        this.id = id;
+        this.name = name;
+        this.startDate = startDate;
+    }
+
+    public Employee(Employee employee) {
+        this.id = employee.id;
+        this.name = employee.name;
+        this.startDate = new Date(employee.startDate.getTime());
+    }
+
+    Date getStartDate() {
+        return startDate;
+    }
+
+    public Employee copy() {
+        return new Employee(this);
+    }
+}

core-java-modules/core-java-lang-oop-2/src/main/java/com/baeldung/copyconstructor/Manager.java

@@ -0,0 +1,31 @@
+package com.baeldung.copyconstructor;
+
+import java.util.Date;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class Manager extends Employee {
+
+    private List<Employee> directReports;
+
+    public Manager(int id, String name, Date startDate, List<Employee> directReports) {
+        super(id, name, startDate);
+        this.directReports = directReports;
+    }
+
+    public Manager(Manager manager) {
+        super(manager.id, manager.name, manager.startDate);
+        this.directReports = manager.directReports.stream()
+          .collect(Collectors.toList());
+    }
+
+    @Override
+    public Employee copy() {
+        return new Manager(this);
+    }
+
+    List<Employee> getDirectReport() {
+        return this.directReports;
+    }
+
+}

core-java-modules/core-java-lang-oop-2/src/test/java/com/baeldung/copyconstructor/EmployeeUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.copyconstructor;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+
+import java.util.Date;
+
+import org.junit.Test;
+
+public class EmployeeUnitTest {
+    @Test
+    public void givenCopyConstructor_whenDeepCopy_thenDistinct() {
+        Date d1 = new Date(123);
+        Employee e1 = new Employee(1, "Baeldung", d1);
+        Employee e2 = new Employee(e1);
+        assertEquals(d1, e1.getStartDate());
+        assertEquals(d1, e2.getStartDate());
+
+        d1.setTime(456);
+        assertEquals(d1, e1.getStartDate());
+        assertNotEquals(d1, e2.getStartDate());
+    }
+
+    @Test
+    public void givenCopyMethod_whenCopy_thenDistinct() {
+        Date d1 = new Date(123);
+        Employee e1 = new Employee(1, "Baeldung", d1);
+        Employee e2 = e1.copy();
+        assertEquals(d1, e1.getStartDate());
+        assertEquals(d1, e2.getStartDate());
+
+        d1.setTime(456);
+        assertEquals(d1, e1.getStartDate());
+        assertNotEquals(d1, e2.getStartDate());
+    }
+}

core-java-modules/core-java-lang-oop-2/src/test/java/com/baeldung/copyconstructor/ManagerUnitTest.java

@@ -0,0 +1,67 @@
+package com.baeldung.copyconstructor;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+
+import org.junit.Test;
+
+public class ManagerUnitTest {
+    @Test
+    public void givenCopyConstructor_whenDeepCopy_thenDistinct() {
+        Date startDate = new Date(123);
+        Employee e1 = new Employee(1, "Baeldung", startDate);
+        Employee e2 = new Employee(e1);
+        List<Employee> directReports = new ArrayList<Employee>();
+        directReports.add(e1);
+        directReports.add(e2);
+
+        Manager m1 = new Manager(1, "Baeldung Manager", startDate, directReports);
+        Manager m2 = new Manager(m1);
+        List<Employee> directReports1 = m1.getDirectReport();
+        List<Employee> directReports2 = m2.getDirectReport();
+        assertEquals(directReports1.size(), directReports2.size());
+        assertArrayEquals(directReports1.toArray(), directReports2.toArray());
+
+        // clear m1's direct reports list. m2's list should not be affected
+        directReports.clear();
+        directReports1 = m1.getDirectReport();
+        directReports2 = m2.getDirectReport();
+        assertEquals(0, directReports1.size());
+        assertEquals(2, directReports2.size());
+
+    }
+
+    @Test
+    public void givenCopyMethod_whenCopy_thenDistinct() {
+        Date startDate = new Date(123);
+        Employee e1 = new Employee(1, "Baeldung", startDate);
+        Employee e2 = new Employee(e1);
+        List<Employee> directReports = new ArrayList<Employee>();
+        directReports.add(e1);
+        directReports.add(e2);
+
+        // a Manager object whose declaration type is Employee.
+        Employee source = new Manager(1, "Baeldung Manager", startDate, directReports);
+        Employee clone = source.copy();
+
+        // after copy, clone should be still a Manager object.
+        assertTrue(clone instanceof Manager);
+        List<Employee> directReports1 = ((Manager) source).getDirectReport();
+        List<Employee> directReports2 = ((Manager) clone).getDirectReport();
+        assertEquals(directReports1.size(), directReports2.size());
+        assertArrayEquals(directReports1.toArray(), directReports2.toArray());
+
+        // clear source's direct reports list. clone's list should not be affected
+        directReports.clear();
+        directReports1 = ((Manager) source).getDirectReport();
+        directReports2 = ((Manager) clone).getDirectReport();
+        assertEquals(0, directReports1.size());
+        assertEquals(2, directReports2.size());
+
+    }
+}

core-java-modules/core-java-lang-operators/src/main/java/com/baeldung/booleanoperators/Car.java

@@ -0,0 +1,36 @@
+package com.baeldung.booleanoperators;
+
+public class Car {
+
+    private boolean diesel;
+    private boolean manual;
+
+    public Car(boolean diesel, boolean manual) {
+        this.diesel = diesel;
+        this.manual = manual;
+    }
+
+    public boolean isDiesel() {
+        return diesel;
+    }
+
+    public boolean isManual() {
+        return manual;
+    }
+
+    static Car dieselAndManualCar() {
+        return new Car(true, true);
+    }
+
+    static Car dieselAndAutomaticCar() {
+        return new Car(true, false);
+    }
+
+    static Car oilAndManualCar() {
+        return new Car(false, true);
+    }
+
+    static Car oilAndAutomaticCar() {
+        return new Car(false, false);
+    }
+}

core-java-modules/core-java-lang-operators/src/test/java/com/baeldung/booleanoperators/XorUnitTest.java

@@ -0,0 +1,69 @@
+package com.baeldung.booleanoperators;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class XorUnitTest {
+
+    @Test
+    void givenDieselManualCar_whenXorOldSchool_thenFalse() {
+        Car car = Car.dieselAndManualCar();
+        boolean dieselXorManual = (car.isDiesel() && !car.isManual()) || (!car.isDiesel() && car.isManual());
+        assertThat(dieselXorManual).isFalse();
+    }
+
+    @Test
+    void givenDieselAutomaticCar_whenXorOldSchool_thenTrue() {
+        Car car = Car.dieselAndAutomaticCar();
+        boolean dieselXorManual = (car.isDiesel() && !car.isManual()) || (!car.isDiesel() && car.isManual());
+        assertThat(dieselXorManual).isTrue();
+    }
+
+    @Test
+    void givenNonDieselManualCar_whenXorOldSchool_thenTrue() {
+        Car car = Car.oilAndManualCar();
+        boolean dieselXorManual = (car.isDiesel() && !car.isManual()) || (!car.isDiesel() && car.isManual());
+        assertThat(dieselXorManual).isTrue();
+    }
+
+    @Test
+    void givenNonDieselAutomaticCar_whenXorOldSchool_thenFalse() {
+        Car car = Car.oilAndAutomaticCar();
+        boolean dieselXorManual = (car.isDiesel() && !car.isManual()) || (!car.isDiesel() && car.isManual());
+        assertThat(dieselXorManual).isFalse();
+    }
+
+    @Test
+    void givenDieselManualCar_whenXor_thenFalse() {
+        Car car = Car.dieselAndManualCar();
+        boolean dieselXorManual = car.isDiesel() ^ car.isManual();
+        assertThat(dieselXorManual).isFalse();
+    }
+
+    @Test
+    void givenDieselAutomaticCar_whenXor_thenTrue() {
+        Car car = Car.dieselAndAutomaticCar();
+        boolean dieselXorManual = car.isDiesel() ^ car.isManual();
+        assertThat(dieselXorManual).isTrue();
+    }
+
+    @Test
+    void givenNonDieselManualCar_whenXor_thenTrue() {
+        Car car = Car.oilAndManualCar();
+        boolean dieselXorManual = car.isDiesel() ^ car.isManual();
+        assertThat(dieselXorManual).isTrue();
+    }
+
+    @Test
+    void givenNonDieselAutomaticCar_whenXor_thenFalse() {
+        Car car = Car.oilAndAutomaticCar();
+        boolean dieselXorManual = car.isDiesel() ^ car.isManual();
+        assertThat(dieselXorManual).isFalse();
+    }
+    
+    @Test
+    void givenNumbersOneAndThree_whenXor_thenTwo() {
+        assertThat(1 ^ 3).isEqualTo(2);
+    }
+}

core-java-modules/core-java/src/main/java/com/baeldung/uuid/UUIDGenerator.java

@@ -3,6 +3,7 @@ package com.baeldung.uuid;
 import java.io.UnsupportedEncodingException;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
 import java.util.UUID;
 
 public class UUIDGenerator {
@@ -65,9 +66,9 @@ public class UUIDGenerator {
         try {
             md = MessageDigest.getInstance("SHA-1");
         } catch (NoSuchAlgorithmException nsae) {
-            throw new InternalError("MD5 not supported", nsae);
+            throw new InternalError("SHA-1 not supported", nsae);
         }
-        byte[] bytes = md.digest(name);
+        byte[] bytes = Arrays.copyOfRange(md.digest(name), 0, 16);
         bytes[6] &= 0x0f; /* clear version        */
         bytes[6] |= 0x50; /* set to version 5     */
         bytes[8] &= 0x3f; /* clear variant        */

javaxval/README.md

@@ -2,9 +2,6 @@
 
 ## Java Bean Validation Examples
 
-###The Course
-The "REST With Spring" Classes: http://bit.ly/restwithspring
-
 ### Relevant Articles: 
 - [Java Bean Validation Basics](http://www.baeldung.com/javax-validation)
 - [Validating Container Elements with Bean Validation 2.0](http://www.baeldung.com/bean-validation-container-elements)

mapstruct/src/main/java/com/baeldung/dto/CustomerDto.java

@@ -0,0 +1,25 @@
+package com.baeldung.dto;
+
+public class CustomerDto {
+
+    private String forename;
+    private String surname;
+
+    public String getForename() {
+        return forename;
+    }
+
+    public CustomerDto setForename(String forename) {
+        this.forename = forename;
+        return this;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public CustomerDto setSurname(String surname) {
+        this.surname = surname;
+        return this;
+    }
+}

mapstruct/src/main/java/com/baeldung/entity/Address.java

@@ -0,0 +1,35 @@
+package com.baeldung.entity;
+
+public class Address {
+
+    private String street;
+    private String postalcode;
+    private String county;
+
+    public String getStreet() {
+        return street;
+    }
+
+    public Address setStreet(String street) {
+        this.street = street;
+        return this;
+    }
+
+    public String getPostalcode() {
+        return postalcode;
+    }
+
+    public Address setPostalcode(String postalcode) {
+        this.postalcode = postalcode;
+        return this;
+    }
+
+    public String getCounty() {
+        return county;
+    }
+
+    public Address setCounty(String county) {
+        this.county = county;
+        return this;
+    }
+}

mapstruct/src/main/java/com/baeldung/entity/Customer.java

@@ -0,0 +1,25 @@
+package com.baeldung.entity;
+
+public class Customer {
+
+    private String firstName;
+    private String lastName;
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public Customer setFirstName(String firstName) {
+        this.firstName = firstName;
+        return this;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public Customer setLastName(String lastName) {
+        this.lastName = lastName;
+        return this;
+    }
+}

mapstruct/src/main/java/com/baeldung/entity/DeliveryAddress.java

@@ -0,0 +1,55 @@
+package com.baeldung.entity;
+
+public class DeliveryAddress {
+
+    private String forename;
+    private String surname;
+    private String street;
+    private String postalcode;
+    private String county;
+
+    public String getForename() {
+        return forename;
+    }
+
+    public DeliveryAddress setForename(String forename) {
+        this.forename = forename;
+        return this;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public DeliveryAddress setSurname(String surname) {
+        this.surname = surname;
+        return this;
+    }
+
+    public String getStreet() {
+        return street;
+    }
+
+    public DeliveryAddress setStreet(String street) {
+        this.street = street;
+        return this;
+    }
+
+    public String getPostalcode() {
+        return postalcode;
+    }
+
+    public DeliveryAddress setPostalcode(String postalcode) {
+        this.postalcode = postalcode;
+        return this;
+    }
+
+    public String getCounty() {
+        return county;
+    }
+
+    public DeliveryAddress setCounty(String county) {
+        this.county = county;
+        return this;
+    }
+}

mapstruct/src/main/java/com/baeldung/mapper/CustomerDtoMapper.java

@@ -0,0 +1,15 @@
+package com.baeldung.mapper;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+
+import com.baeldung.dto.CustomerDto;
+import com.baeldung.entity.Customer;
+
+@Mapper
+public interface CustomerDtoMapper {
+
+    @Mapping(source = "firstName", target = "forename")
+    @Mapping(source = "lastName", target = "surname")
+    CustomerDto from(Customer customer);
+}

mapstruct/src/main/java/com/baeldung/mapper/DeliveryAddressMapper.java

@@ -0,0 +1,24 @@
+package com.baeldung.mapper;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.mapstruct.MappingTarget;
+
+import com.baeldung.entity.Address;
+import com.baeldung.entity.Customer;
+import com.baeldung.entity.DeliveryAddress;
+
+@Mapper
+public interface DeliveryAddressMapper {
+
+    @Mapping(source = "customer.firstName", target = "forename")
+    @Mapping(source = "customer.lastName", target = "surname")
+    @Mapping(source = "address.street", target = "street")
+    @Mapping(source = "address.postalcode", target = "postalcode")
+    @Mapping(source = "address.county", target = "county")
+    DeliveryAddress from(Customer customer, Address address);
+
+    @Mapping(source = "address.postalcode", target = "postalcode")
+    @Mapping(source = "address.county", target = "county")
+    DeliveryAddress updateAddress(@MappingTarget DeliveryAddress deliveryAddress, Address address);
+}

mapstruct/src/test/java/com/baeldung/mapper/CustomerDtoMapperUnitTest.java

@@ -0,0 +1,29 @@
+package com.baeldung.mapper;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.jupiter.api.Test;
+import org.mapstruct.factory.Mappers;
+
+import com.baeldung.dto.CustomerDto;
+import com.baeldung.entity.Customer;
+
+public class CustomerDtoMapperUnitTest {
+
+    private CustomerDtoMapper customerDtoMapper = Mappers.getMapper(CustomerDtoMapper.class);
+
+    @Test
+    void testGivenCustomer_mapsToCustomerDto() {
+
+        // given
+        Customer customer = new Customer().setFirstName("Max")
+            .setLastName("Powers");
+
+        // when
+        CustomerDto customerDto = customerDtoMapper.from(customer);
+
+        // then
+        assertEquals(customerDto.getForename(), customer.getFirstName());
+        assertEquals(customerDto.getSurname(), customer.getLastName());
+    }
+}

mapstruct/src/test/java/com/baeldung/mapper/DeliveryAddressMapperUnitTest.java

@@ -0,0 +1,64 @@
+package com.baeldung.mapper;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertSame;
+
+import org.junit.Test;
+import org.mapstruct.factory.Mappers;
+
+import com.baeldung.entity.Address;
+import com.baeldung.entity.Customer;
+import com.baeldung.entity.DeliveryAddress;
+
+public class DeliveryAddressMapperUnitTest {
+
+    private DeliveryAddressMapper deliveryAddressMapper = Mappers.getMapper(DeliveryAddressMapper.class);
+
+    @Test
+    public void testGivenCustomerAndAddress_mapsToDeliveryAddress() {
+
+        // given
+        Customer customer = new Customer().setFirstName("Max")
+            .setLastName("Powers");
+
+        Address homeAddress = new Address().setStreet("123 Some Street")
+            .setCounty("Nevada")
+            .setPostalcode("89123");
+
+        // when
+        DeliveryAddress deliveryAddress = deliveryAddressMapper.from(customer, homeAddress);
+
+        // then
+        assertEquals(deliveryAddress.getForename(), customer.getFirstName());
+        assertEquals(deliveryAddress.getSurname(), customer.getLastName());
+        assertEquals(deliveryAddress.getStreet(), homeAddress.getStreet());
+        assertEquals(deliveryAddress.getCounty(), homeAddress.getCounty());
+        assertEquals(deliveryAddress.getPostalcode(), homeAddress.getPostalcode());
+    }
+
+    @Test
+    public void testGivenDeliveryAddressAndSomeOtherAddress_updatesDeliveryAddress() {
+
+        // given
+        Customer customer = new Customer().setFirstName("Max")
+            .setLastName("Powers");
+
+        DeliveryAddress deliveryAddress = new DeliveryAddress().setStreet("123 Some Street")
+            .setCounty("Nevada")
+            .setPostalcode("89123");
+
+        Address otherAddress = new Address().setStreet("456 Some other street")
+            .setCounty("Arizona")
+            .setPostalcode("12345");
+
+        // when
+        DeliveryAddress updatedDeliveryAddress = deliveryAddressMapper.updateAddress(deliveryAddress, otherAddress);
+
+        // then
+        assertSame(deliveryAddress, updatedDeliveryAddress);
+
+        assertEquals(deliveryAddress.getStreet(), otherAddress.getStreet());
+        assertEquals(deliveryAddress.getCounty(), otherAddress.getCounty());
+        assertEquals(deliveryAddress.getPostalcode(), otherAddress.getPostalcode());
+    }
+}

ml/README.md

@@ -0,0 +1,5 @@
+### Logistic Regression in Java
+This is a soft introduction to ML using [deeplearning4j](https://deeplearning4j.org) library
+
+### Relevant Articles:
+- [Logistic Regression in Java](http://www.baeldung.com/)

ml/pom.xml

@@ -0,0 +1,52 @@
+<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/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.deeplearning4j</groupId>
+    <artifactId>ml</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <name>Machine Learning</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.nd4j</groupId>
+            <artifactId>nd4j-native-platform</artifactId>
+            <version>${dl4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.deeplearning4j</groupId>
+            <artifactId>deeplearning4j-core</artifactId>
+            <version>${dl4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.deeplearning4j</groupId>
+            <artifactId>deeplearning4j-nn</artifactId>
+            <version>${dl4j.version}</version>
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/org.datavec/datavec-api -->
+        <dependency>
+            <groupId>org.datavec</groupId>
+            <artifactId>datavec-api</artifactId>
+            <version>${dl4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <version>4.3.5</version>
+        </dependency>
+
+
+    </dependencies>
+
+    <properties>
+        <dl4j.version>1.0.0-beta4</dl4j.version>
+    </properties>
+
+</project>

ml/src/main/java/com/baeldung/logreg/MnistClassifier.java

@@ -0,0 +1,168 @@
+package com.baeldung.logreg;
+
+import java.io.File;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Random;
+
+import org.datavec.api.io.labels.ParentPathLabelGenerator;
+import org.datavec.api.split.FileSplit;
+import org.datavec.image.loader.NativeImageLoader;
+import org.datavec.image.recordreader.ImageRecordReader;
+import org.deeplearning4j.datasets.datavec.RecordReaderDataSetIterator;
+import org.deeplearning4j.nn.conf.MultiLayerConfiguration;
+import org.deeplearning4j.nn.conf.NeuralNetConfiguration;
+import org.deeplearning4j.nn.conf.inputs.InputType;
+import org.deeplearning4j.nn.conf.layers.ConvolutionLayer;
+import org.deeplearning4j.nn.conf.layers.DenseLayer;
+import org.deeplearning4j.nn.conf.layers.OutputLayer;
+import org.deeplearning4j.nn.conf.layers.SubsamplingLayer;
+import org.deeplearning4j.nn.multilayer.MultiLayerNetwork;
+import org.deeplearning4j.nn.weights.WeightInit;
+import org.deeplearning4j.optimize.listeners.ScoreIterationListener;
+import org.deeplearning4j.util.ModelSerializer;
+import org.nd4j.evaluation.classification.Evaluation;
+import org.nd4j.linalg.activations.Activation;
+import org.nd4j.linalg.dataset.api.iterator.DataSetIterator;
+import org.nd4j.linalg.dataset.api.preprocessor.DataNormalization;
+import org.nd4j.linalg.dataset.api.preprocessor.ImagePreProcessingScaler;
+import org.nd4j.linalg.learning.config.Nesterovs;
+import org.nd4j.linalg.lossfunctions.LossFunctions;
+import org.nd4j.linalg.schedule.MapSchedule;
+import org.nd4j.linalg.schedule.ScheduleType;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Handwritten digit image classification based on LeNet-5 architecture by Yann LeCun.
+ * 
+ * This code accompanies the article "Logistic  regression in Java" and is heavily based on 
+ * <a href="https://github.com/deeplearning4j/dl4j-examples/blob/master/dl4j-examples/src/main/java/org/deeplearning4j/examples/convolution/mnist/MnistClassifier.java">MnistClassifier</a>. 
+ * Some minor changes have been made in order to make article's flow smoother.
+ * 
+ */
+
+public class MnistClassifier {
+    private static final Logger logger = LoggerFactory.getLogger(MnistClassifier.class);
+    private static final String basePath = System.getProperty("java.io.tmpdir") + "mnist" + File.separator;
+    private static final File modelPath = new File(basePath + "mnist-model.zip");
+    private static final String dataUrl = "http://github.com/myleott/mnist_png/raw/master/mnist_png.tar.gz";
+
+    public static void main(String[] args) throws Exception {
+        // input image sizes in pixels
+        int height = 28;
+        int width = 28;
+        // input image colour depth (1 for gray scale images)
+        int channels = 1;
+        // the number of output classes
+        int outputClasses = 10;
+        // number of samples that will be propagated through the network in each iteration
+        int batchSize = 54;
+        // total number of training epochs
+        int epochs = 1;
+
+        // initialize a pseudorandom number generator
+        int seed = 1234;
+        Random randNumGen = new Random(seed);
+
+        final String path = basePath + "mnist_png" + File.separator;
+        if (!new File(path).exists()) {
+            logger.info("Downloading data {}", dataUrl);
+            String localFilePath = basePath + "mnist_png.tar.gz";
+            File file = new File(localFilePath);
+            if (!file.exists()) {
+                file.getParentFile()
+                    .mkdirs();
+                Utils.downloadAndSave(dataUrl, file);
+                Utils.extractTarArchive(file, basePath);
+            }
+        } else {
+            logger.info("Using the local data from folder {}", path);
+        }
+
+        logger.info("Vectorizing the data from folder {}", path);
+        // vectorization of train data
+        File trainData = new File(path + "training");
+        FileSplit trainSplit = new FileSplit(trainData, NativeImageLoader.ALLOWED_FORMATS, randNumGen);
+        // use parent directory name as the image label
+        ParentPathLabelGenerator labelMaker = new ParentPathLabelGenerator();
+        ImageRecordReader trainRR = new ImageRecordReader(height, width, channels, labelMaker);
+        trainRR.initialize(trainSplit);
+        DataSetIterator train = new RecordReaderDataSetIterator(trainRR, batchSize, 1, outputClasses);
+
+        // pixel values from 0-255 to 0-1 (min-max scaling)
+        DataNormalization imageScaler = new ImagePreProcessingScaler();
+        imageScaler.fit(train);
+        train.setPreProcessor(imageScaler);
+
+        // vectorization of test data
+        File testData = new File(path + "testing");
+        FileSplit testSplit = new FileSplit(testData, NativeImageLoader.ALLOWED_FORMATS, randNumGen);
+        ImageRecordReader testRR = new ImageRecordReader(height, width, channels, labelMaker);
+        testRR.initialize(testSplit);
+        DataSetIterator test = new RecordReaderDataSetIterator(testRR, batchSize, 1, outputClasses);
+        // same normalization for better results
+        test.setPreProcessor(imageScaler);
+
+        logger.info("Network configuration and training...");
+        // reduce the learning rate as the number of training epochs increases
+        // iteration #, learning rate
+        Map<Integer, Double> learningRateSchedule = new HashMap<>();
+        learningRateSchedule.put(0, 0.06);
+        learningRateSchedule.put(200, 0.05);
+        learningRateSchedule.put(600, 0.028);
+        learningRateSchedule.put(800, 0.0060);
+        learningRateSchedule.put(1000, 0.001);
+
+        final ConvolutionLayer layer1 = new ConvolutionLayer.Builder(5, 5).nIn(channels)
+            .stride(1, 1)
+            .nOut(20)
+            .activation(Activation.IDENTITY)
+            .build();
+        final SubsamplingLayer layer2 = new SubsamplingLayer.Builder(SubsamplingLayer.PoolingType.MAX).kernelSize(2, 2)
+            .stride(2, 2)
+            .build();
+        // nIn need not specified in later layers
+        final ConvolutionLayer layer3 = new ConvolutionLayer.Builder(5, 5).stride(1, 1)
+            .nOut(50)
+            .activation(Activation.IDENTITY)
+            .build();
+        final DenseLayer layer4 = new DenseLayer.Builder().activation(Activation.RELU)
+            .nOut(500)
+            .build();
+        final OutputLayer layer5 = new OutputLayer.Builder(LossFunctions.LossFunction.NEGATIVELOGLIKELIHOOD).nOut(outputClasses)
+            .activation(Activation.SOFTMAX)
+            .build();
+        final MultiLayerConfiguration config = new NeuralNetConfiguration.Builder().seed(seed)
+            .l2(0.0005) // ridge regression value
+            .updater(new Nesterovs(new MapSchedule(ScheduleType.ITERATION, learningRateSchedule)))
+            .weightInit(WeightInit.XAVIER)
+            .list()
+            .layer(layer1)
+            .layer(layer2)
+            .layer(layer3)
+            .layer(layer2)
+            .layer(layer4)
+            .layer(layer5)
+            .setInputType(InputType.convolutionalFlat(height, width, channels))
+            .build();
+
+        final MultiLayerNetwork model = new MultiLayerNetwork(config);
+        model.init();
+        model.setListeners(new ScoreIterationListener(100));
+        logger.info("Total num of params: {}", model.numParams());
+
+        // evaluation while training (the score should go down)
+        for (int i = 0; i < epochs; i++) {
+            model.fit(train);
+            logger.info("Completed epoch {}", i);
+            train.reset();
+            test.reset();
+        }
+        Evaluation eval = model.evaluate(test);
+        logger.info(eval.stats());
+
+        ModelSerializer.writeModel(model, modelPath, true);
+        logger.info("The MINIST model has been saved in {}", modelPath.getPath());
+    }
+}

ml/src/main/java/com/baeldung/logreg/MnistPrediction.java

@@ -0,0 +1,57 @@
+package com.baeldung.logreg;
+
+import java.io.File;
+import java.io.IOException;
+
+import javax.swing.JFileChooser;
+
+import org.datavec.image.loader.NativeImageLoader;
+import org.deeplearning4j.nn.multilayer.MultiLayerNetwork;
+import org.deeplearning4j.util.ModelSerializer;
+import org.nd4j.linalg.api.ndarray.INDArray;
+import org.nd4j.linalg.dataset.api.preprocessor.ImagePreProcessingScaler;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class MnistPrediction {
+    private static final Logger logger = LoggerFactory.getLogger(MnistPrediction.class);
+    private static final File modelPath = new File(System.getProperty("java.io.tmpdir") + "mnist" + File.separator + "mnist-model.zip");
+    private static final int height = 28;
+    private static final int width = 28;
+    private static final int channels = 1;
+
+    /**
+     * Opens a popup that allows to select a file from the filesystem.
+     * @return
+     */
+    public static String fileChose() {
+        JFileChooser fc = new JFileChooser();
+        int ret = fc.showOpenDialog(null);
+        if (ret == JFileChooser.APPROVE_OPTION) {
+            File file = fc.getSelectedFile();
+            return file.getAbsolutePath();
+        } else {
+            return null;
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        if (!modelPath.exists()) {
+            logger.info("The model not found. Have you trained it?");
+            return;
+        }
+        MultiLayerNetwork model = ModelSerializer.restoreMultiLayerNetwork(modelPath);
+        String path = fileChose();
+        File file = new File(path);
+
+        INDArray image = new NativeImageLoader(height, width, channels).asMatrix(file);
+        new ImagePreProcessingScaler(0, 1).transform(image);
+
+        // Pass through to neural Net
+        INDArray output = model.output(image);
+
+        logger.info("File: {}", path);
+        logger.info("Probabilities: {}", output);
+    }
+
+}

ml/src/main/java/com/baeldung/logreg/Utils.java

@@ -0,0 +1,103 @@
+package com.baeldung.logreg;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+import org.apache.commons.compress.archivers.ArchiveEntry;
+import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
+import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
+import org.apache.commons.compress.compressors.gzip.GzipCompressorInputStream;
+import org.apache.http.HttpEntity;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Utility class for digit classifier.
+ * 
+ */
+public class Utils {
+
+    private static final Logger logger = LoggerFactory.getLogger(Utils.class);
+
+    private Utils() {
+    }
+
+    /**
+     * Download the content of the given url and save it into a file.
+     * @param url
+     * @param file
+     */
+    public static void downloadAndSave(String url, File file) throws IOException {
+        CloseableHttpClient client = HttpClientBuilder.create()
+            .build();
+        logger.info("Connecting to {}", url);
+        try (CloseableHttpResponse response = client.execute(new HttpGet(url))) {
+            HttpEntity entity = response.getEntity();
+            if (entity != null) {
+                logger.info("Downloaded {} bytes", entity.getContentLength());
+                try (FileOutputStream outstream = new FileOutputStream(file)) {
+                    logger.info("Saving to the local file");
+                    entity.writeTo(outstream);
+                    outstream.flush();
+                    logger.info("Local file saved");
+                }
+            }
+        }
+    }
+
+    /**
+     * Extract a "tar.gz" file into a given folder.
+     * @param file
+     * @param folder 
+     */
+    public static void extractTarArchive(File file, String folder) throws IOException {
+        logger.info("Extracting archive {} into folder {}", file.getName(), folder);
+        // @formatter:off
+        try (FileInputStream fis = new FileInputStream(file);
+            BufferedInputStream bis = new BufferedInputStream(fis);
+            GzipCompressorInputStream gzip = new GzipCompressorInputStream(bis); 
+            TarArchiveInputStream tar = new TarArchiveInputStream(gzip)) {
+       // @formatter:on
+            TarArchiveEntry entry;
+            while ((entry = (TarArchiveEntry) tar.getNextEntry()) != null) {
+                extractEntry(entry, tar, folder);
+            }
+        }
+      logger.info("Archive extracted"); 
+    }
+
+    /**
+     * Extract an entry of the input stream into a given folder
+     * @param entry
+     * @param tar
+     * @param folder
+     * @throws IOException
+     */
+    public static void extractEntry(ArchiveEntry entry, InputStream tar, String folder) throws IOException {
+        final int bufferSize = 4096;
+        final String path = folder + entry.getName();
+        if (entry.isDirectory()) {
+            new File(path).mkdirs();
+        } else {
+            int count;
+            byte[] data = new byte[bufferSize];
+            // @formatter:off
+            try (FileOutputStream os = new FileOutputStream(path); 
+                BufferedOutputStream dest = new BufferedOutputStream(os, bufferSize)) {
+           // @formatter:off
+                while ((count = tar.read(data, 0, bufferSize)) != -1) {
+                    dest.write(data, 0, count);
+                }
+            }
+        }
+    }
+}