Merge remote-tracking branch 'origin/master'

apache-poi/README.md

@@ -1,2 +1,3 @@
 ### Relevant Articles:
 - [Microsoft Word Processing in Java with Apache POI](http://www.baeldung.com/java-microsoft-word-with-apache-poi)
+- [Working with Microsoft Excel in Java](http://www.baeldung.com/java-microsoft-excel)

core-java/pom.xml

@@ -1,5 +1,5 @@
 <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">
+         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</artifactId>
@@ -10,6 +10,44 @@
 
     <dependencies>
 
+        <dependency>
+            <groupId>org.neo4j</groupId>
+            <artifactId>neo4j</artifactId>
+            <version>3.1.0</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.neo4j.driver</groupId>
+            <artifactId>neo4j-java-driver</artifactId>
+            <version>1.1.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.neo4j</groupId>
+            <artifactId>neo4j-jdbc-driver</artifactId>
+            <version>3.0.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.neo4j</groupId>
+            <artifactId>neo4j-ogm-core</artifactId>
+            <version>2.1.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.neo4j</groupId>
+            <artifactId>neo4j-ogm-embedded-driver</artifactId>
+            <version>2.1.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.google.inject</groupId>
+            <artifactId>guice</artifactId>
+            <version>4.1.0</version>
+            <classifier>no_aop</classifier>
+            <scope>test</scope>
+        </dependency>
+
         <!-- utils -->
         <dependency>
             <groupId>net.sourceforge.collections</groupId>
@@ -63,7 +101,6 @@
             <artifactId>grep4j</artifactId>
             <version>${grep4j.version}</version>
         </dependency>
-        
         <!-- web -->
 
         <!-- marshalling -->
@@ -269,7 +306,8 @@
                         <configuration>
                             <shadedArtifactAttached>true</shadedArtifactAttached>
                             <transformers>
-                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                <transformer
+                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                     <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
                                 </transformer>
                             </transformers>

core-java/src/main/java/com/baeldung/graph/Car.java

@@ -0,0 +1,50 @@
+package com.baeldung.graph;
+
+import org.neo4j.ogm.annotation.GraphId;
+import org.neo4j.ogm.annotation.NodeEntity;
+import org.neo4j.ogm.annotation.Relationship;
+
+/**
+ * @author Danil Kornishev (danil.kornishev@mastercard.com)
+ */
+@NodeEntity
+public class Car {
+    @GraphId
+    private Long id;
+
+    private String make;
+
+    @Relationship(direction = "INCOMING")
+    private Company company;
+
+    public Car(String make, String model) {
+        this.make = make;
+        this.model = model;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getMake() {
+        return make;
+    }
+
+    public void setMake(String make) {
+        this.make = make;
+    }
+
+    public String getModel() {
+        return model;
+    }
+
+    public void setModel(String model) {
+        this.model = model;
+    }
+
+    private String model;
+}

core-java/src/main/java/com/baeldung/graph/Company.java

@@ -0,0 +1,45 @@
+package com.baeldung.graph;
+
+import org.neo4j.ogm.annotation.NodeEntity;
+import org.neo4j.ogm.annotation.Relationship;
+
+/**
+ * @author Danil Kornishev (danil.kornishev@mastercard.com)
+ */
+@NodeEntity
+public class Company {
+    private Long id;
+
+    private String name;
+
+    @Relationship(type="owns")
+    private Car car;
+
+    public Company(String name) {
+        this.name = name;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Car getCar() {
+        return car;
+    }
+
+    public void setCar(Car car) {
+        this.car = car;
+    }
+}

core-java/src/main/java/com/baeldung/java_8_features/groupingby/BlogPost.java

@@ -0,0 +1,36 @@
+package com.baeldung.java_8_features.groupingby;
+
+public class BlogPost {
+    private String title;
+    private String author;
+    private BlogPostType type;
+    private int likes;
+
+    public BlogPost(String title, String author, BlogPostType type, int likes) {
+        this.title = title;
+        this.author = author;
+        this.type = type;
+        this.likes = likes;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public String getAuthor() {
+        return author;
+    }
+
+    public BlogPostType getType() {
+        return type;
+    }
+
+    public int getLikes() {
+        return likes;
+    }
+
+    @Override
+    public String toString() {
+        return "BlogPost{" + "title='" + title + '\'' + ", type=" + type + ", likes=" + likes + '}';
+    }
+}

core-java/src/main/java/com/baeldung/java_8_features/groupingby/BlogPostType.java

@@ -0,0 +1,5 @@
+package com.baeldung.java_8_features.groupingby;
+
+public enum BlogPostType {
+    NEWS, REVIEW, GUIDE
+}

core-java/src/test/java/com/baeldung/graph/Neo4JServerTest.java

@@ -0,0 +1,60 @@
+package com.baeldung.graph;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.ResultSet;
+import java.sql.Statement;
+
+import org.junit.Ignore;
+import org.junit.Test;
+import org.neo4j.driver.v1.AuthTokens;
+import org.neo4j.driver.v1.Driver;
+import org.neo4j.driver.v1.GraphDatabase;
+import org.neo4j.driver.v1.Session;
+import org.neo4j.driver.v1.StatementResult;
+import org.testng.Assert;
+
+@Ignore
+public class Neo4JServerTest {
+
+    @Test
+    public void standAloneDriver() {
+        Driver driver = GraphDatabase.driver("bolt://localhost:7687", AuthTokens.basic("neo4j", "12345"));
+        Session session = driver.session();
+
+        session.run("CREATE (baeldung:Company {name:\"Baeldung\"}) " +
+                "-[:owns]-> (tesla:Car {make: 'tesla', model: 'modelX'})" +
+                "RETURN baeldung, tesla");
+
+        StatementResult result = session.run("MATCH (company:Company)-[:owns]-> (car:Car)" +
+                "WHERE car.make='tesla' and car.model='modelX'" +
+                "RETURN company.name");
+
+        Assert.assertTrue(result.hasNext());
+        Assert.assertEquals(result.next().get("company.name").asString(), "Baeldung");
+
+        session.close();
+        driver.close();
+    }
+    
+    @Test
+    public void standAloneJdbc() throws Exception {
+        Connection con = DriverManager.getConnection("jdbc:neo4j:bolt://localhost/?user=neo4j,password=12345,scheme=basic");
+
+        // Querying
+        try (Statement stmt = con.createStatement()) {
+            stmt.execute("CREATE (baeldung:Company {name:\"Baeldung\"}) " +
+                    "-[:owns]-> (tesla:Car {make: 'tesla', model: 'modelX'})" +
+                    "RETURN baeldung, tesla");
+
+            ResultSet rs = stmt.executeQuery("MATCH (company:Company)-[:owns]-> (car:Car)" +
+                    "WHERE car.make='tesla' and car.model='modelX'" +
+                    "RETURN company.name");
+
+            while (rs.next()) {
+                Assert.assertEquals(rs.getString("company.name"), "Baeldung");
+            }
+        }
+        con.close();
+    }
+}

core-java/src/test/java/com/baeldung/graph/Neo4jOgmTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.graph;
+
+import org.junit.Test;
+import org.neo4j.ogm.config.Configuration;
+import org.neo4j.ogm.model.Result;
+import org.neo4j.ogm.session.Session;
+import org.neo4j.ogm.session.SessionFactory;
+import org.testng.Assert;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @author Danil Kornishev (danil.kornishev@mastercard.com)
+ */
+public class Neo4jOgmTest {
+
+    @Test
+    public void testOgm() {
+        Configuration conf = new Configuration();
+        conf.driverConfiguration().setDriverClassName("org.neo4j.ogm.drivers.embedded.driver.EmbeddedDriver");
+
+        SessionFactory factory = new SessionFactory(conf, "com.baeldung.graph");
+        Session session = factory.openSession();
+
+        Car tesla = new Car("tesla", "modelS");
+        Company baeldung = new Company("baeldung");
+
+        baeldung.setCar(tesla);
+
+        session.save(baeldung);
+
+        Map<String, String> params = new HashMap<>();
+        params.put("make", "tesla");
+        Result result = session.query("MATCH (car:Car) <-[:owns]- (company:Company)" +
+                " WHERE car.make=$make" +
+                " RETURN company", params);
+
+        Map<String, Object> firstResult = result.iterator().next();
+
+        Assert.assertEquals(firstResult.size(), 1);
+
+        Company actual = (Company) firstResult.get("company");
+        Assert.assertEquals(actual.getName(), baeldung.getName());
+    }
+}

core-java/src/test/java/com/baeldung/graph/Neo4jTest.java

@@ -0,0 +1,167 @@
+package com.baeldung.graph;
+
+
+import java.io.File;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.neo4j.graphdb.GraphDatabaseService;
+import org.neo4j.graphdb.Label;
+import org.neo4j.graphdb.Node;
+import org.neo4j.graphdb.NotFoundException;
+import org.neo4j.graphdb.RelationshipType;
+import org.neo4j.graphdb.Result;
+import org.neo4j.graphdb.factory.GraphDatabaseFactory;
+import org.testng.Assert;
+
+public class Neo4jTest {
+
+    private static GraphDatabaseService graphDb;
+
+    @Before
+    public void setUp() {
+        GraphDatabaseFactory graphDbFactory = new GraphDatabaseFactory();
+        graphDb = graphDbFactory.newEmbeddedDatabase(new File("data/cars"));
+    }
+
+    @After
+    public void tearDown() {
+        graphDb.shutdown();
+    }
+
+    @Test
+    public void testPersonCar() {
+        graphDb.beginTx();
+        Node car = graphDb.createNode(Label.label("Car"));
+        car.setProperty("make", "tesla");
+        car.setProperty("model", "model3");
+
+        Node owner = graphDb.createNode(Label.label("Person"));
+        owner.setProperty("firstName", "baeldung");
+        owner.setProperty("lastName", "baeldung");
+
+        owner.createRelationshipTo(car, RelationshipType.withName("owner"));
+
+        Result result = graphDb.execute("MATCH (c:Car) <-[owner]- (p:Person) " +
+                "WHERE c.make = 'tesla'" +
+                "RETURN p.firstName, p.lastName");
+
+        Map<String, Object> firstResult = result.next();
+        Assert.assertEquals("baeldung", firstResult.get("p.firstName"));
+    }
+
+    @Test
+    public void testCreateNode() {
+
+        graphDb.beginTx();
+
+        Result result = graphDb.execute("CREATE (baeldung:Company {name:\"Baeldung\"})" +
+                "RETURN baeldung");
+
+        Map<String, Object> firstResult = result.next();
+        Node firstNode = (Node) firstResult.get("baeldung");
+        Assert.assertEquals(firstNode.getProperty("name"), "Baeldung");
+    }
+
+    @Test
+    public void testCreateNodeAndLink() {
+        graphDb.beginTx();
+
+        Result result = graphDb.execute("CREATE (baeldung:Company {name:\"Baeldung\"}) " +
+                "-[:owns]-> (tesla:Car {make: 'tesla', model: 'modelX'})" +
+                "RETURN baeldung, tesla");
+
+        Map<String, Object> firstResult = result.next();
+        Assert.assertTrue(firstResult.containsKey("baeldung"));
+        Assert.assertTrue(firstResult.containsKey("tesla"));
+    }
+
+    @Test
+    public void testFindAndReturn() {
+        graphDb.beginTx();
+
+        graphDb.execute("CREATE (baeldung:Company {name:\"Baeldung\"}) " +
+                "-[:owns]-> (tesla:Car {make: 'tesla', model: 'modelX'})" +
+                "RETURN baeldung, tesla");
+
+        Result result = graphDb.execute("MATCH (company:Company)-[:owns]-> (car:Car)" +
+                "WHERE car.make='tesla' and car.model='modelX'" +
+                "RETURN company.name");
+
+        Map<String, Object> firstResult = result.next();
+        Assert.assertEquals(firstResult.get("company.name"), "Baeldung");
+    }
+
+    @Test
+    public void testUpdate() {
+        graphDb.beginTx();
+
+        graphDb.execute("CREATE (baeldung:Company {name:\"Baeldung\"}) " +
+                "-[:owns]-> (tesla:Car {make: 'tesla', model: 'modelX'})" +
+                "RETURN baeldung, tesla");
+
+        Result result = graphDb.execute("MATCH (car:Car)" +
+                "WHERE car.make='tesla'" +
+                " SET car.milage=120" +
+                " SET car :Car:Electro" +
+                " SET car.model=NULL" +
+                " RETURN car");
+
+        Map<String, Object> firstResult = result.next();
+        Node car = (Node) firstResult.get("car");
+
+        Assert.assertEquals(car.getProperty("milage"), 120L);
+        Assert.assertEquals(car.getLabels(), Arrays.asList(Label.label("Car"), Label.label("Electro")));
+
+        try {
+            car.getProperty("model");
+            Assert.fail();
+        } catch (NotFoundException e) {
+            // expected
+        }
+    }
+
+    @Test
+    public void testDelete() {
+        graphDb.beginTx();
+
+        graphDb.execute("CREATE (baeldung:Company {name:\"Baeldung\"}) " +
+                "-[:owns]-> (tesla:Car {make: 'tesla', model: 'modelX'})" +
+                "RETURN baeldung, tesla");
+
+        graphDb.execute("MATCH (company:Company)" +
+                " WHERE company.name='Baeldung'" +
+                " DELETE company");
+
+        Result result = graphDb.execute("MATCH (company:Company)" +
+                " WHERE company.name='Baeldung'" +
+                " RETURN company");
+
+        Assert.assertFalse(result.hasNext());
+    }
+
+    @Test
+    public void testBindings() {
+        graphDb.beginTx();
+
+        Map<String, Object> params = new HashMap<>();
+        params.put("name", "baeldung");
+        params.put("make", "tesla");
+        params.put("model", "modelS");
+
+        Result result = graphDb.execute("CREATE (baeldung:Company {name:$name}) " +
+                "-[:owns]-> (tesla:Car {make: $make, model: $model})" +
+                "RETURN baeldung, tesla", params);
+
+        Map<String, Object> firstResult = result.next();
+        Assert.assertTrue(firstResult.containsKey("baeldung"));
+        Assert.assertTrue(firstResult.containsKey("tesla"));
+
+        Node car = (Node) firstResult.get("tesla");
+        Assert.assertEquals(car.getProperty("model"), "modelS");
+    }
+}

core-java/src/test/java/com/baeldung/java/concurrentmodification/ConcurrentModificationUnitTest.java

@@ -0,0 +1,80 @@
+package com.baeldung.java.concurrentmodification;
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.ConcurrentModificationException;
+import java.util.Iterator;
+import java.util.List;
+
+import static java.util.stream.Collectors.toList;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.util.Lists.newArrayList;
+
+public class ConcurrentModificationUnitTest {
+    @Test(expected = ConcurrentModificationException.class)
+    public void givenIterating_whenRemoving_thenThrowException() throws InterruptedException {
+
+        List<Integer> integers = newArrayList(1, 2, 3);
+
+        for (Integer integer : integers) {
+            integers.remove(1);
+        }
+    }
+
+    @Test
+    public void givenIterating_whenUsingIteratorRemove_thenNoError() throws InterruptedException {
+
+        List<Integer> integers = newArrayList(1, 2, 3);
+
+        for (Iterator<Integer> iterator = integers.iterator(); iterator.hasNext();) {
+            Integer integer = iterator.next();
+            if(integer == 2) {
+                iterator.remove();
+            }
+        }
+
+        assertThat(integers).containsExactly(1, 3);
+    }
+
+    @Test
+    public void givenIterating_whenUsingRemovalList_thenNoError() throws InterruptedException {
+
+        List<Integer> integers = newArrayList(1, 2, 3);
+        List<Integer> toRemove = newArrayList();
+
+        for (Integer integer : integers) {
+            if(integer == 2) {
+                toRemove.add(integer);
+            }
+        }
+        integers.removeAll(toRemove);
+
+        assertThat(integers).containsExactly(1, 3);
+    }
+
+    @Test
+    public void whenUsingRemoveIf_thenRemoveElements() throws InterruptedException {
+
+        Collection<Integer> integers = newArrayList(1, 2, 3);
+
+        integers.removeIf(i -> i == 2);
+
+        assertThat(integers).containsExactly(1, 3);
+    }
+
+    @Test
+    public void whenUsingStream_thenRemoveElements() {
+        Collection<Integer> integers = newArrayList(1, 2, 3);
+
+        List<String> collected = integers
+                .stream()
+                .filter(i -> i != 2)
+                .map(Object::toString)
+                .collect(toList());
+
+        assertThat(collected).containsExactly("1", "3");
+    }
+
+}

core-java/src/test/java/com/baeldung/java8/Java8GroupingByCollectorUnitTest.java

@@ -0,0 +1,231 @@
+package com.baeldung.java8;
+
+import com.baeldung.java_8_features.groupingby.BlogPost;
+import com.baeldung.java_8_features.groupingby.BlogPostType;
+import org.junit.Test;
+
+import java.util.*;
+import java.util.concurrent.ConcurrentMap;
+
+import static java.util.Comparator.comparingInt;
+import static java.util.stream.Collectors.*;
+import static org.junit.Assert.*;
+
+public class Java8GroupingByCollectorUnitTest {
+
+    private static final List<BlogPost> posts = Arrays.asList(
+      new BlogPost("News item 1", "Author 1", BlogPostType.NEWS, 15),
+      new BlogPost("Tech review 1", "Author 2", BlogPostType.REVIEW, 5),
+      new BlogPost("Programming guide", "Author 1", BlogPostType.GUIDE, 20),
+      new BlogPost("News item 2", "Author 2", BlogPostType.NEWS, 35),
+      new BlogPost("Tech review 2", "Author 1", BlogPostType.REVIEW, 15));
+
+    @Test
+    public void givenAListOfPosts_whenGroupedByType_thenGetAMapBetweenTypeAndPosts() {
+        Map<BlogPostType, List<BlogPost>> postsPerType = posts
+          .stream()
+          .collect(groupingBy(BlogPost::getType));
+
+        assertEquals(2, postsPerType
+          .get(BlogPostType.NEWS)
+          .size());
+        assertEquals(1, postsPerType
+          .get(BlogPostType.GUIDE)
+          .size());
+        assertEquals(2, postsPerType
+          .get(BlogPostType.REVIEW)
+          .size());
+    }
+
+    @Test
+    public void givenAListOfPosts_whenGroupedByTypeAndTheirTitlesAreJoinedInAString_thenGetAMapBetweenTypeAndCsvTitles() {
+        Map<BlogPostType, String> postsPerType = posts
+          .stream()
+          .collect(groupingBy(BlogPost::getType, mapping(BlogPost::getTitle, joining(", ", "Post titles: [", "]"))));
+
+        assertEquals("Post titles: [News item 1, News item 2]", postsPerType.get(BlogPostType.NEWS));
+        assertEquals("Post titles: [Programming guide]", postsPerType.get(BlogPostType.GUIDE));
+        assertEquals("Post titles: [Tech review 1, Tech review 2]", postsPerType.get(BlogPostType.REVIEW));
+    }
+
+    @Test
+    public void givenAListOfPosts_whenGroupedByTypeAndSumTheLikes_thenGetAMapBetweenTypeAndPostLikes() {
+        Map<BlogPostType, Integer> likesPerType = posts
+          .stream()
+          .collect(groupingBy(BlogPost::getType, summingInt(BlogPost::getLikes)));
+
+        assertEquals(50, likesPerType
+          .get(BlogPostType.NEWS)
+          .intValue());
+        assertEquals(20, likesPerType
+          .get(BlogPostType.REVIEW)
+          .intValue());
+        assertEquals(20, likesPerType
+          .get(BlogPostType.GUIDE)
+          .intValue());
+    }
+
+    @Test
+    public void givenAListOfPosts_whenGroupedByTypeInAnEnumMap_thenGetAnEnumMapBetweenTypeAndPosts() {
+        EnumMap<BlogPostType, List<BlogPost>> postsPerType = posts
+          .stream()
+          .collect(groupingBy(BlogPost::getType, () -> new EnumMap<>(BlogPostType.class), toList()));
+
+        assertEquals(2, postsPerType
+          .get(BlogPostType.NEWS)
+          .size());
+        assertEquals(1, postsPerType
+          .get(BlogPostType.GUIDE)
+          .size());
+        assertEquals(2, postsPerType
+          .get(BlogPostType.REVIEW)
+          .size());
+    }
+
+    @Test
+    public void givenAListOfPosts_whenGroupedByTypeInSets_thenGetAMapBetweenTypesAndSetsOfPosts() {
+        Map<BlogPostType, Set<BlogPost>> postsPerType = posts
+          .stream()
+          .collect(groupingBy(BlogPost::getType, toSet()));
+
+        assertEquals(2, postsPerType
+          .get(BlogPostType.NEWS)
+          .size());
+        assertEquals(1, postsPerType
+          .get(BlogPostType.GUIDE)
+          .size());
+        assertEquals(2, postsPerType
+          .get(BlogPostType.REVIEW)
+          .size());
+    }
+
+    @Test
+    public void givenAListOfPosts_whenGroupedByTypeConcurrently_thenGetAMapBetweenTypeAndPosts() {
+        ConcurrentMap<BlogPostType, List<BlogPost>> postsPerType = posts
+          .parallelStream()
+          .collect(groupingByConcurrent(BlogPost::getType));
+
+        assertEquals(2, postsPerType
+          .get(BlogPostType.NEWS)
+          .size());
+        assertEquals(1, postsPerType
+          .get(BlogPostType.GUIDE)
+          .size());
+        assertEquals(2, postsPerType
+          .get(BlogPostType.REVIEW)
+          .size());
+    }
+
+    @Test
+    public void givenAListOfPosts_whenGroupedByTypeAndAveragingLikes_thenGetAMapBetweenTypeAndAverageNumberOfLikes() {
+        Map<BlogPostType, Double> averageLikesPerType = posts
+          .stream()
+          .collect(groupingBy(BlogPost::getType, averagingInt(BlogPost::getLikes)));
+
+        assertEquals(25, averageLikesPerType
+          .get(BlogPostType.NEWS)
+          .intValue());
+        assertEquals(20, averageLikesPerType
+          .get(BlogPostType.GUIDE)
+          .intValue());
+        assertEquals(10, averageLikesPerType
+          .get(BlogPostType.REVIEW)
+          .intValue());
+    }
+
+    @Test
+    public void givenAListOfPosts_whenGroupedByTypeAndCounted_thenGetAMapBetweenTypeAndNumberOfPosts() {
+        Map<BlogPostType, Long> numberOfPostsPerType = posts
+          .stream()
+          .collect(groupingBy(BlogPost::getType, counting()));
+
+        assertEquals(2, numberOfPostsPerType
+          .get(BlogPostType.NEWS)
+          .intValue());
+        assertEquals(1, numberOfPostsPerType
+          .get(BlogPostType.GUIDE)
+          .intValue());
+        assertEquals(2, numberOfPostsPerType
+          .get(BlogPostType.REVIEW)
+          .intValue());
+    }
+
+    @Test
+    public void givenAListOfPosts_whenGroupedByTypeAndMaxingLikes_thenGetAMapBetweenTypeAndMaximumNumberOfLikes() {
+        Map<BlogPostType, Optional<BlogPost>> maxLikesPerPostType = posts
+          .stream()
+          .collect(groupingBy(BlogPost::getType, maxBy(comparingInt(BlogPost::getLikes))));
+
+        assertTrue(maxLikesPerPostType
+          .get(BlogPostType.NEWS)
+          .isPresent());
+        assertEquals(35, maxLikesPerPostType
+          .get(BlogPostType.NEWS)
+          .get()
+          .getLikes());
+
+        assertTrue(maxLikesPerPostType
+          .get(BlogPostType.GUIDE)
+          .isPresent());
+        assertEquals(20, maxLikesPerPostType
+          .get(BlogPostType.GUIDE)
+          .get()
+          .getLikes());
+
+        assertTrue(maxLikesPerPostType
+          .get(BlogPostType.REVIEW)
+          .isPresent());
+        assertEquals(15, maxLikesPerPostType
+          .get(BlogPostType.REVIEW)
+          .get()
+          .getLikes());
+    }
+
+    @Test
+    public void givenAListOfPosts_whenGroupedByAuthorAndThenByType_thenGetAMapBetweenAuthorAndMapsBetweenTypeAndBlogPosts() {
+        Map<String, Map<BlogPostType, List<BlogPost>>> map = posts
+          .stream()
+          .collect(groupingBy(BlogPost::getAuthor, groupingBy(BlogPost::getType)));
+
+        assertEquals(1, map
+          .get("Author 1")
+          .get(BlogPostType.NEWS)
+          .size());
+        assertEquals(1, map
+          .get("Author 1")
+          .get(BlogPostType.GUIDE)
+          .size());
+        assertEquals(1, map
+          .get("Author 1")
+          .get(BlogPostType.REVIEW)
+          .size());
+
+        assertEquals(1, map
+          .get("Author 2")
+          .get(BlogPostType.NEWS)
+          .size());
+        assertEquals(1, map
+          .get("Author 2")
+          .get(BlogPostType.REVIEW)
+          .size());
+        assertNull(map
+          .get("Author 2")
+          .get(BlogPostType.GUIDE));
+    }
+
+    @Test
+    public void givenAListOfPosts_whenGroupedByTypeAndSummarizingLikes_thenGetAMapBetweenTypeAndSummary() {
+        Map<BlogPostType, IntSummaryStatistics> likeStatisticsPerType = posts
+          .stream()
+          .collect(groupingBy(BlogPost::getType, summarizingInt(BlogPost::getLikes)));
+
+        IntSummaryStatistics newsLikeStatistics = likeStatisticsPerType.get(BlogPostType.NEWS);
+
+        assertEquals(2, newsLikeStatistics.getCount());
+        assertEquals(50, newsLikeStatistics.getSum());
+        assertEquals(25.0, newsLikeStatistics.getAverage(), 0.001);
+        assertEquals(35, newsLikeStatistics.getMax());
+        assertEquals(15, newsLikeStatistics.getMin());
+    }
+
+}

spring-jersey/pom.xml

@@ -9,7 +9,7 @@
     <packaging>war</packaging>
 
     <properties>
-        <jersey.version>2.25</jersey.version>
+        <jersey.version>2.25.1</jersey.version>
         <jcl.slf4j.version>1.7.22</jcl.slf4j.version>
         <logback.version>1.1.8</logback.version>
         <junit.version>4.12</junit.version>

spring-jersey/src/main/java/com/baeldung/client/rest/RestClient.java

@@ -18,7 +18,7 @@ public class RestClient {
     }
 
     public Employee getJsonEmployee(int id) {
-        return client.target(REST_URI).path(new Integer(id).toString()).request(MediaType.APPLICATION_JSON).get(Employee.class);
+        return client.target(REST_URI).path(String.valueOf(id)).request(MediaType.APPLICATION_JSON).get(Employee.class);
     }
 
     public Response createXmlEmployee(Employee emp) {
@@ -26,6 +26,6 @@ public class RestClient {
     }
 
     public Employee getXmlEmployee(int id) {
-        return client.target(REST_URI).path(new Integer(id).toString()).request(MediaType.APPLICATION_XML).get(Employee.class);
+        return client.target(REST_URI).path(String.valueOf(id)).request(MediaType.APPLICATION_XML).get(Employee.class);
     }
 }

spring-mvc-forms/pom.xml

@@ -46,6 +46,23 @@
         	<artifactId>commons-fileupload</artifactId>
         	<version>${fileupload.version}</version>
         </dependency>
+        
+         <dependency>
+            <groupId>org.springframework.security</groupId>
+            <artifactId>spring-security-web</artifactId>
+            <version>${org.springframework.security.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.security</groupId>
+            <artifactId>spring-security-config</artifactId>
+            <version>${org.springframework.security.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.security</groupId>
+            <artifactId>spring-security-taglibs</artifactId>
+            <version>${org.springframework.security.version}</version>
+        </dependency>
+        
     </dependencies>
     <profiles>
         <!-- Local -->
@@ -98,6 +115,7 @@
         <hibernate-validator.version>5.3.3.Final</hibernate-validator.version>
         <deploy-path>enter-location-of-server</deploy-path>
 		<fileupload.version>1.3.2</fileupload.version>
+		<org.springframework.security.version>4.2.1.RELEASE</org.springframework.security.version>
     </properties>
 
 </project>

spring-mvc-forms/src/main/java/com/baeldung/springmvcforms/configuration/SecurityConfig.java

@@ -0,0 +1,122 @@
+package com.baeldung.springmvcforms.configuration;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.annotation.Order;
+import org.springframework.security.authentication.AuthenticationProvider;
+import org.springframework.security.authentication.TestingAuthenticationProvider;
+import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
+import org.springframework.security.core.userdetails.User;
+import org.springframework.security.core.userdetails.UserDetailsService;
+import org.springframework.security.provisioning.InMemoryUserDetailsManager;
+
+@Configuration
+@EnableWebSecurity
+public class SecurityConfig {
+
+    @Bean
+    public UserDetailsService userDetailsService() throws Exception {
+        InMemoryUserDetailsManager manager = new InMemoryUserDetailsManager();
+        manager.createUser(User.withUsername("user")
+            .password("userPass")
+            .roles("USER")
+            .build());
+        manager.createUser(User.withUsername("admin")
+            .password("adminPass")
+            .roles("ADMIN")
+            .build());
+        return manager;
+    }
+
+    @Configuration
+    @Order(1)
+    public static class App1ConfigurationAdapter extends WebSecurityConfigurerAdapter {
+
+        public App1ConfigurationAdapter() {
+            super();
+        }
+
+        @Override
+        protected void configure(AuthenticationManagerBuilder auth) throws Exception {
+            auth.inMemoryAuthentication()
+                .withUser("admin")
+                .password("admin")
+                .roles("ADMIN");
+        }
+
+        @Override
+        protected void configure(HttpSecurity http) throws Exception {
+            http.antMatcher("/admin*")
+                .authorizeRequests()
+                .anyRequest()
+                .hasRole("ADMIN")
+                // log in
+                .and()
+                .formLogin()
+                .loginPage("/loginAdmin")
+                .loginProcessingUrl("/admin_login")
+                .failureUrl("/loginAdmin?error=loginError")
+                .defaultSuccessUrl("/adminPage")
+                // logout
+                .and()
+                .logout()
+                .logoutUrl("/admin_logout")
+                .logoutSuccessUrl("/protectedLinks")
+                .deleteCookies("JSESSIONID")
+                .and()
+                .exceptionHandling()
+                .accessDeniedPage("/403")
+                .and()
+                .csrf()
+                .disable();
+        }
+    }
+
+    @Configuration
+    @Order(2)
+    public static class App2ConfigurationAdapter extends WebSecurityConfigurerAdapter {
+
+        public App2ConfigurationAdapter() {
+            super();
+        }
+
+        @Override
+        protected void configure(AuthenticationManagerBuilder auth) throws Exception {
+            auth.inMemoryAuthentication()
+                .withUser("user")
+                .password("user")
+                .roles("USER");
+        }
+
+        protected void configure(HttpSecurity http) throws Exception {
+            http.antMatcher("/user*")
+                .authorizeRequests()
+                .anyRequest()
+                .hasRole("USER")
+                // log in
+                .and()
+                .formLogin()
+                .loginPage("/loginUser")
+                .loginProcessingUrl("/user_login")
+                .failureUrl("/loginUser?error=loginError")
+                .defaultSuccessUrl("/userPage")
+                // logout
+                .and()
+                .logout()
+                .logoutUrl("/user_logout")
+                .logoutSuccessUrl("/protectedLinks")
+                .deleteCookies("JSESSIONID")
+                .and()
+                .exceptionHandling()
+                .accessDeniedPage("/403")
+                .and()
+                .csrf()
+                .disable();
+        }
+    }
+
+}

spring-mvc-forms/src/main/java/com/baeldung/springmvcforms/configuration/WebInitializer.java

@@ -3,6 +3,7 @@ package com.baeldung.springmvcforms.configuration;
 import org.springframework.web.WebApplicationInitializer;
 import org.springframework.web.context.ContextLoaderListener;
 import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
+import org.springframework.web.filter.DelegatingFilterProxy;
 import org.springframework.web.servlet.DispatcherServlet;
 
 import javax.servlet.ServletContext;
@@ -24,6 +25,9 @@ public class WebInitializer implements WebApplicationInitializer {
 
 		servlet.setLoadOnStartup(1);
 		servlet.addMapping("/");
+		
+		container.addFilter("springSecurityFilterChain", new DelegatingFilterProxy("springSecurityFilterChain"))
+        .addMappingForUrlPatterns(null, false, "/*");
 	}
 //	@Override
 //	public void onStartup(ServletContext container) {

spring-mvc-forms/src/main/java/com/baeldung/springmvcforms/controller/UsersController.java

@@ -0,0 +1,38 @@
+package com.baeldung.springmvcforms.controller;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+
+@Controller
+public class UsersController {
+
+    @RequestMapping("/protectedLinks")
+    public String getAnonymousPage() {
+        return "protectedLinks";
+    }
+
+    @RequestMapping("/userPage")
+    public String getUserPage() {
+        return "userPage";
+    }
+
+    @RequestMapping("/adminPage")
+    public String getAdminPage() {
+        return "adminPage";
+    }
+
+    @RequestMapping("/loginAdmin")
+    public String getAdminLoginPage() {
+        return "loginAdmin";
+    }
+
+    @RequestMapping("/loginUser")
+    public String getUserLoginPage() {
+        return "loginUser";
+    }
+
+    @RequestMapping("/403")
+    public String getAccessDeniedPage() {
+        return "403";
+    }
+}

spring-mvc-forms/src/main/webapp/WEB-INF/views/403.jsp

@@ -0,0 +1,12 @@
+<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
+    pageEncoding="ISO-8859-1"%>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<title></title>
+</head>
+<body>
+Your do not have permission to view this page.
+</body>
+</html>

spring-mvc-forms/src/main/webapp/WEB-INF/views/adminPage.jsp

@@ -0,0 +1,16 @@
+<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
+    pageEncoding="ISO-8859-1"%>
+<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<title>Insert title here</title>
+</head>
+<body>
+Welcome admin! <a href="<c:url value='/admin_logout' /> " >Logout</a>
+
+<br /><br />
+<a href="<c:url value='/protectedLinks' /> " >Back to links</a>
+</body>
+</html>

spring-mvc-forms/src/main/webapp/WEB-INF/views/loginAdmin.jsp

@@ -0,0 +1,38 @@
+<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
+	pageEncoding="ISO-8859-1"%>
+<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<title>Insert title here</title>
+</head>
+<body>
+
+    <p>Admin login page</p>
+    <form name="f" action="admin_login" method="POST">
+
+        <table>
+            <tr>
+                <td>User:</td>
+                <td><input type="text" name="username" value=""></td>
+            </tr>
+            <tr>
+                <td>Password:</td>
+                <td><input type="password" name="password" /></td>
+            </tr>
+            <tr>
+                <td><input name="submit" type="submit" value="submit" /></td>
+            </tr>
+        </table>
+
+    </form>
+
+    <%
+        if (request.getParameter("error") != null) {
+            out.println("Login failed!");
+        }
+    %>
+
+</body>
+</html>

spring-mvc-forms/src/main/webapp/WEB-INF/views/loginUser.jsp

@@ -0,0 +1,37 @@
+<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
+	pageEncoding="ISO-8859-1"%>
+<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<title>Login</title>
+</head>
+<body>
+
+    <p>User login page</p>
+	
+    <form name="f" action="user_login" method="POST">	
+        <table>
+            <tr>
+                <td>User:</td>
+                <td><input type="text" name="username" value=""></td>
+            </tr>
+            <tr>
+                <td>Password:</td>
+                <td><input type="password" name="password" /></td>
+            </tr>
+            <tr>
+                <td><input name="submit" type="submit" value="submit" /></td>
+            </tr>
+        </table>
+
+    </form>
+    <%
+        if (request.getParameter("error") != null) {
+            out.println("Login failed!");
+        }
+    %>
+
+</body>
+</html>

spring-mvc-forms/src/main/webapp/WEB-INF/views/protectedLinks.jsp

@@ -0,0 +1,16 @@
+<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
+    pageEncoding="ISO-8859-1"%>
+<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<title>Insert title here</title>
+</head>
+<body>
+
+<a href="<c:url value="/userPage" />">User page</a>
+<br />
+<a href="<c:url value="/adminPage" />">Admin page</a>
+</body>
+</html>

spring-mvc-forms/src/main/webapp/WEB-INF/views/userPage.jsp

@@ -0,0 +1,15 @@
+<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
+    pageEncoding="ISO-8859-1"%>
+<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<title>Insert title here</title>
+</head>
+<body>
+Welcome user! <a href="<c:url value='/user_logout' /> " >Logout</a>
+<br /><br />
+<a href="<c:url value='/protectedLinks' /> " >Back to links</a>
+</body>
+</html>