Merge remote-tracking branch 'upstream/master'

.gitignore

@@ -85,7 +85,5 @@ transaction.log
 *-shell.log
 
 apache-cxf/cxf-aegis/baeldung.xml
-apache-fop/src/test/resources/input.xml
+
-apache-fop/src/test/resources/output_herold.pdf
+libraries-2/*.db
-apache-fop/src/test/resources/output_html2fo.pdf
-apache-fop/src/test/resources/output_jtidy.pdf

algorithms-miscellaneous-2/src/test/java/com/baeldung/jgrapht/GraphImageGenerationUnitTest.java

@@ -1,16 +1,21 @@
 package com.baeldung.jgrapht;
 
 import static org.junit.Assert.assertTrue;
+
 import java.awt.Color;
 import java.awt.image.BufferedImage;
 import java.io.File;
 import java.io.IOException;
+
 import javax.imageio.ImageIO;
+
 import org.jgrapht.ext.JGraphXAdapter;
 import org.jgrapht.graph.DefaultDirectedGraph;
 import org.jgrapht.graph.DefaultEdge;
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
+
 import com.mxgraph.layout.mxCircleLayout;
 import com.mxgraph.layout.mxIGraphLayout;
 import com.mxgraph.util.mxCellRenderer;
@@ -20,7 +25,7 @@ public class GraphImageGenerationUnitTest {
 
     @Before
     public void createGraph() throws IOException {
-        File imgFile = new File("src/test/resources/graph.png");
+        File imgFile = new File("src/test/resources/graph1.png");
         imgFile.createNewFile();
         g = new DefaultDirectedGraph<String, DefaultEdge>(DefaultEdge.class);
         String x1 = "x1";
@@ -34,12 +39,18 @@ public class GraphImageGenerationUnitTest {
         g.addEdge(x3, x1);
     }
 
+    @After
+    public void cleanup() {
+        File imgFile = new File("src/test/resources/graph1.png");
+        imgFile.deleteOnExit();
+    }
+
     @Test
     public void givenAdaptedGraph_whenWriteBufferedImage_ThenFileShouldExist() throws IOException {
         JGraphXAdapter<String, DefaultEdge> graphAdapter = new JGraphXAdapter<String, DefaultEdge>(g);
         mxIGraphLayout layout = new mxCircleLayout(graphAdapter);
         layout.execute(graphAdapter.getDefaultParent());
-        File imgFile = new File("src/test/resources/graph.png");
+        File imgFile = new File("src/test/resources/graph1.png");
         BufferedImage image = mxCellRenderer.createBufferedImage(graphAdapter, null, 2, Color.WHITE, true, null);
         ImageIO.write(image, "PNG", imgFile);
         assertTrue(imgFile.exists());

algorithms-miscellaneous-6/README.md

@@ -7,4 +7,6 @@
 - [Efficiently Merge Sorted Java Sequences](https://www.baeldung.com/java-merge-sorted-sequences)
 - [Introduction to Greedy Algorithms with Java](https://www.baeldung.com/java-greedy-algorithms)
 - [The Caesar Cipher in Java](https://www.baeldung.com/java-caesar-cipher)
+- [Implementing a 2048 Solver in Java](https://www.baeldung.com/2048-java-solver)
+- [Finding Top K Elements in an Array](https://www.baeldung.com/java-array-top-elements)
 - More articles: [[<-- prev]](/../algorithms-miscellaneous-5)

algorithms-miscellaneous-6/src/main/java/com/baeldung/algorithms/play2048/Play2048.java

@@ -1,7 +1,7 @@
 package com.baeldung.algorithms.play2048;
 
 public class Play2048 {
-    private static final int SIZE = 3;
+    private static final int SIZE = 4;
     private static final int INITIAL_NUMBERS = 2;
 
     public static void main(String[] args) {

algorithms-miscellaneous-6/src/main/java/com/baeldung/algorithms/topkelements/BruteForceTopKElementsFinder.java

@@ -0,0 +1,26 @@
+package com.baeldung.algorithms.topkelements;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class BruteForceTopKElementsFinder implements TopKElementsFinder<Integer> {
+
+    public List<Integer> findTopK(List<Integer> input, int k) {
+        List<Integer> array = new ArrayList<>(input);
+        List<Integer> topKList = new ArrayList<>();
+
+        for (int i = 0; i < k; i++) {
+            int maxIndex = 0;
+
+            for (int j = 1; j < array.size(); j++) {
+                if (array.get(j) > array.get(maxIndex)) {
+                    maxIndex = j;
+                }
+            }
+
+            topKList.add(array.remove(maxIndex));
+        }
+
+        return topKList;
+    }
+}

algorithms-miscellaneous-6/src/main/java/com/baeldung/algorithms/topkelements/MaxHeapTopKElementsFinder.java

@@ -0,0 +1,26 @@
+package com.baeldung.algorithms.topkelements;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.PriorityQueue;
+
+public class MaxHeapTopKElementsFinder implements TopKElementsFinder<Integer> {
+
+    public List<Integer> findTopK(List<Integer> input, int k) {
+        PriorityQueue<Integer> maxHeap = new PriorityQueue<>();
+
+        input.forEach(number -> {
+            maxHeap.add(number);
+
+            if (maxHeap.size() > k) {
+                maxHeap.poll();
+            }
+        });
+
+        List<Integer> topKList = new ArrayList<>(maxHeap);
+        Collections.reverse(topKList);
+
+        return topKList;
+    }
+}

algorithms-miscellaneous-6/src/main/java/com/baeldung/algorithms/topkelements/TopKElementsFinder.java

@@ -0,0 +1,7 @@
+package com.baeldung.algorithms.topkelements;
+
+import java.util.List;
+
+public interface TopKElementsFinder<T extends Comparable<T>> {
+    List<T> findTopK(List<T> input, int k);
+}

algorithms-miscellaneous-6/src/main/java/com/baeldung/algorithms/topkelements/TreeSetTopKElementsFinder.java

@@ -0,0 +1,17 @@
+package com.baeldung.algorithms.topkelements;
+
+import java.util.Comparator;
+import java.util.List;
+import java.util.Set;
+import java.util.TreeSet;
+import java.util.stream.Collectors;
+
+public class TreeSetTopKElementsFinder implements TopKElementsFinder<Integer> {
+
+    public List<Integer> findTopK(List<Integer> input, int k) {
+        Set<Integer> sortedSet = new TreeSet<>(Comparator.reverseOrder());
+        sortedSet.addAll(input);
+
+        return sortedSet.stream().limit(k).collect(Collectors.toList());
+    }
+}

algorithms-miscellaneous-6/src/test/java/com/baeldung/algorithms/topkelements/TopKElementsFinderUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.algorithms.topkelements;
+
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.List;
+
+import static org.assertj.core.api.Java6Assertions.assertThat;
+
+public class TopKElementsFinderUnitTest {
+    private final TopKElementsFinder<Integer> bruteForceFinder = new BruteForceTopKElementsFinder();
+    private final TopKElementsFinder<Integer> maxHeapFinder = new MaxHeapTopKElementsFinder();
+    private final TopKElementsFinder<Integer> treeSetFinder = new TreeSetTopKElementsFinder();
+
+    private final int k = 4;
+    private final List<Integer> distinctIntegers = Arrays.asList(1, 2, 3, 9, 7, 6, 12);
+    private final List<Integer> distinctIntegersTopK = Arrays.asList(9, 7, 6, 12);
+    private final List<Integer> nonDistinctIntegers = Arrays.asList(1, 2, 3, 3, 9, 9, 7, 6, 12);
+    private final List<Integer> nonDistinctIntegersTopK = Arrays.asList(9, 9, 7, 12);
+
+
+    @Test
+    public void givenArrayDistinctIntegers_whenBruteForceFindTopK_thenReturnKLargest() {
+        assertThat(bruteForceFinder.findTopK(distinctIntegers, k)).containsOnlyElementsOf(distinctIntegersTopK);
+    }
+
+    @Test
+    public void givenArrayDistinctIntegers_whenMaxHeapFindTopK_thenReturnKLargest() {
+        assertThat(maxHeapFinder.findTopK(distinctIntegers, k)).containsOnlyElementsOf(distinctIntegersTopK);
+    }
+
+    @Test
+    public void givenArrayDistinctIntegers_whenTreeSetFindTopK_thenReturnKLargest() {
+        assertThat(treeSetFinder.findTopK(distinctIntegers, k)).containsOnlyElementsOf(distinctIntegersTopK);
+    }
+
+    @Test
+    public void givenArrayNonDistinctIntegers_whenBruteForceFindTopK_thenReturnKLargest() {
+        assertThat(bruteForceFinder.findTopK(nonDistinctIntegers, k)).containsOnlyElementsOf(nonDistinctIntegersTopK);
+    }
+
+    @Test
+    public void givenArrayNonDistinctIntegers_whenMaxHeapFindTopK_thenReturnKLargest() {
+        assertThat(maxHeapFinder.findTopK(nonDistinctIntegers, k)).containsOnlyElementsOf(nonDistinctIntegersTopK);
+    }
+}

apache-avro/README.md

@@ -1,6 +0,0 @@
-## Apache Avro
-
-This module contains articles about Apache Avro
-
-### Relevant Articles:
-- [Guide to Apache Avro](https://www.baeldung.com/java-apache-avro)

apache-avro/pom.xml

@@ -1,72 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project
-    xmlns="http://maven.apache.org/POM/4.0.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-    <artifactId>apache-avro</artifactId>
-    <version>0.0.1-SNAPSHOT</version>
-    <name>apache-avro</name>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-    </parent>
-
-    <dependencies>
-        <dependency>
-            <groupId>org.slf4j</groupId>
-            <artifactId>slf4j-simple</artifactId>
-            <version>${slf4j.version}</version>
-            <scope>compile</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.avro</groupId>
-            <artifactId>avro</artifactId>
-            <version>${avro.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.avro</groupId>
-            <artifactId>avro-compiler</artifactId>
-            <version>${avro.version}</version>
-        </dependency>
-
-        <dependency>
-            <groupId>org.apache.avro</groupId>
-            <artifactId>avro-maven-plugin</artifactId>
-            <version>${avro.version}</version>
-        </dependency>
-    </dependencies>
-
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.avro</groupId>
-                <artifactId>avro-maven-plugin</artifactId>
-                <version>${avro.version}</version>
-                <executions>
-                    <execution>
-                        <id>schemas</id>
-                        <phase>generate-sources</phase>
-                        <goals>
-                            <goal>schema</goal>
-                            <goal>protocol</goal>
-                            <goal>idl-protocol</goal>
-                        </goals>
-                        <configuration>
-                            <sourceDirectory>${project.basedir}/src/main/resources/</sourceDirectory>
-                            <outputDirectory>${project.basedir}/src/main/java/</outputDirectory>
-                        </configuration>
-                    </execution>
-                </executions>
-            </plugin>
-        </plugins>
-    </build>
-
-    <properties>
-        <avro.version>1.8.2</avro.version>
-        <slf4j.version>1.7.25</slf4j.version>
-    </properties>
-
-</project>

apache-beam/README.md

@@ -1,3 +0,0 @@
-### Relevant Articles:
-
-- [Introduction to Apache Beam](https://www.baeldung.com/apache-beam)

apache-beam/pom.xml

@@ -1,43 +0,0 @@
-<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>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-    </parent>
-
-    <groupId>com.baeldung.apache</groupId>
-    <artifactId>apache-beam</artifactId>
-    <version>0.0.1-SNAPSHOT</version>
-
-    <dependencies>
-        <dependency>
-            <groupId>org.apache.beam</groupId>
-            <artifactId>beam-sdks-java-core</artifactId>
-            <version>${beam.version}</version>
-        </dependency>
-        <!-- runtime scoped -->
-        <dependency>
-            <groupId>org.apache.beam</groupId>
-            <artifactId>beam-runners-direct-java</artifactId>
-            <version>${beam.version}</version>
-            <scope>runtime</scope>
-        </dependency>
-        <!-- test scoped -->
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
-    <properties>
-        <beam.version>2.19.0</beam.version>
-        <assertj.version>3.6.1</assertj.version>
-    </properties>
-
-</project>

apache-bval/README.md

@@ -1,7 +0,0 @@
-## Apache BVal
-
-This module contains articles about Apache BVal
-
-### Relevant Articles:
-
-- [Intro to Apache BVal](https://www.baeldung.com/apache-bval)

apache-bval/pom.xml

@@ -1,40 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project
-    xmlns="http://maven.apache.org/POM/4.0.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-    <artifactId>apache-bval</artifactId>
-    <version>0.0.1-SNAPSHOT</version>
-    <name>apache-bval</name>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-    </parent>
-
-    <dependencies>
-        <dependency>
-            <groupId>org.apache.bval</groupId>
-            <artifactId>bval-jsr</artifactId>
-            <version>${bval.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>javax.validation</groupId>
-            <artifactId>validation-api</artifactId>
-            <version>${javax.validation.validation-api.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.bval</groupId>
-            <artifactId>bval-extras</artifactId>
-            <version>${bval.version}</version>
-        </dependency>
-    </dependencies>
-
-    <properties>
-        <bval.version>1.1.2</bval.version>
-        <javax.validation.validation-api.version>1.1.0.Final</javax.validation.validation-api.version>
-    </properties>
-
-</project>

apache-curator/README.md

@@ -1,7 +0,0 @@
-## Apache Curator
-
-This module contains articles about Apache Curator
-
-### Relevant Articles:
-
-- [Introduction to Apache Curator](https://www.baeldung.com/apache-curator)

apache-curator/pom.xml

@@ -1,70 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project
-    xmlns="http://maven.apache.org/POM/4.0.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-    <artifactId>apache-curator</artifactId>
-    <version>0.0.1-SNAPSHOT</version>
-    <name>apache-curator</name>
-    <packaging>jar</packaging>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-    </parent>
-
-    <dependencies>
-        <!-- curator -->
-        <dependency>
-            <groupId>org.apache.curator</groupId>
-            <artifactId>curator-x-async</artifactId>
-            <version>${curator.version}</version>
-            <exclusions>
-                <exclusion>
-                    <groupId>org.apache.zookeeper</groupId>
-                    <artifactId>zookeeper</artifactId>
-                </exclusion>
-            </exclusions>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.curator</groupId>
-            <artifactId>curator-recipes</artifactId>
-            <version>${curator.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.zookeeper</groupId>
-            <artifactId>zookeeper</artifactId>
-            <version>${zookeeper.version}</version>
-        </dependency>
-        <!-- utils -->
-        <dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
-            <version>${jackson.version}</version>
-        </dependency>
-        <!-- test scoped -->
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>com.jayway.awaitility</groupId>
-            <artifactId>awaitility</artifactId>
-            <version>${avaitility.version}</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
-    <properties>
-        <curator.version>4.0.1</curator.version>
-        <zookeeper.version>3.4.11</zookeeper.version>
-        <!-- testing -->
-        <assertj.version>3.6.1</assertj.version>
-        <avaitility.version>1.7.0</avaitility.version>
-    </properties>
-
-</project>

apache-geode/README.md

@@ -1,7 +0,0 @@
-## Apache Geode
-
-This module contains articles about Apache Geode
-
-### Relevant Articles: 
-
-- [A Quick Guide to Apache Geode](https://www.baeldung.com/apache-geode)

apache-geode/pom.xml

@@ -1,29 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project
-    xmlns="http://maven.apache.org/POM/4.0.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-    <artifactId>apache-geode</artifactId>
-    <version>1.0-SNAPSHOT</version>
-    <name>apache-geode</name>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-    </parent>
-
-    <dependencies>
-        <dependency>
-            <groupId>org.apache.geode</groupId>
-            <artifactId>geode-core</artifactId>
-            <version>${geode.core}</version>
-        </dependency>
-    </dependencies>
-
-    <properties>
-        <geode.core>1.6.0</geode.core>
-    </properties>
-
-</project>

apache-libraries/README.md

@@ -0,0 +1,15 @@
+## Apache Libraries
+
+This module contains articles about various Apache libraries and utilities
+
+### Relevant Articles:
+- [Guide to Apache Avro](https://www.baeldung.com/java-apache-avro)
+- [Introduction to Apache Beam](https://www.baeldung.com/apache-beam)
+- [Intro to Apache BVal](https://www.baeldung.com/apache-bval)
+- [Building a Microservice with Apache Meecrowave](https://www.baeldung.com/apache-meecrowave)
+- [Intro to Apache OpenNLP](https://www.baeldung.com/apache-open-nlp)
+- [Introduction to Apache Pulsar](https://www.baeldung.com/apache-pulsar)
+- [Getting Started with Java and Zookeeper](https://www.baeldung.com/java-zookeeper)
+- [Introduction to Apache Curator](https://www.baeldung.com/apache-curator)
+- [A Quick Guide to Apache Geode](https://www.baeldung.com/apache-geode)
+- [Guide to Solr in Java with Apache Solrj](https://www.baeldung.com/apache-solrj)

apache-libraries/pom.xml

@@ -0,0 +1,223 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>apache-libraries</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>apache-libraries</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <!-- avro -->
+        <dependency>
+            <groupId>org.apache.avro</groupId>
+            <artifactId>avro</artifactId>
+            <version>${avro.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.avro</groupId>
+            <artifactId>avro-compiler</artifactId>
+            <version>${avro.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.avro</groupId>
+            <artifactId>avro-maven-plugin</artifactId>
+            <version>${avro.version}</version>
+        </dependency>
+
+        <!-- beam -->
+        <dependency>
+            <groupId>org.apache.beam</groupId>
+            <artifactId>beam-sdks-java-core</artifactId>
+            <version>${beam.version}</version>
+        </dependency>
+        <!-- runtime scoped -->
+        <dependency>
+            <groupId>org.apache.beam</groupId>
+            <artifactId>beam-runners-direct-java</artifactId>
+            <version>${beam.version}</version>
+            <scope>runtime</scope>
+        </dependency>
+
+        <!-- bval -->
+        <dependency>
+            <groupId>org.apache.bval</groupId>
+            <artifactId>bval-jsr</artifactId>
+            <version>${bval.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>javax.validation</groupId>
+            <artifactId>validation-api</artifactId>
+            <version>${javax.validation.validation-api.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.bval</groupId>
+            <artifactId>bval-extras</artifactId>
+            <version>${bval.version}</version>
+        </dependency>
+
+        <!-- meecrowave -->
+        <dependency>
+            <groupId>org.apache.meecrowave</groupId>
+            <artifactId>meecrowave-core</artifactId>
+            <version>${meecrowave-core.version}</version>
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/org.apache.meecrowave/meecrowave-jpa -->
+        <dependency>
+            <groupId>org.apache.meecrowave</groupId>
+            <artifactId>meecrowave-jpa</artifactId>
+            <version>${meecrowave-jpa.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.squareup.okhttp3</groupId>
+            <artifactId>okhttp</artifactId>
+            <version>${okhttp.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.meecrowave</groupId>
+            <artifactId>meecrowave-junit</artifactId>
+            <version>${meecrowave-junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+        
+        <!-- opennlp -->
+        <dependency>
+            <groupId>org.apache.opennlp</groupId>
+            <artifactId>opennlp-tools</artifactId>
+            <version>${opennlp.opennlp-tools.version}</version>
+        </dependency>
+        
+        <!-- pulsar -->
+        <dependency>
+            <groupId>org.apache.pulsar</groupId>
+            <artifactId>pulsar-client</artifactId>
+            <version>${pulsar-client.version}</version>
+            <scope>compile</scope>
+        </dependency>
+        
+        <!-- zookeeper -->
+        <dependency>
+            <groupId>org.apache.zookeeper</groupId>
+            <artifactId>zookeeper</artifactId>
+            <version>${zookeeper.version}</version>
+        </dependency>
+        
+        <!-- curator -->
+        <dependency>
+            <groupId>org.apache.curator</groupId>
+            <artifactId>curator-x-async</artifactId>
+            <version>${curator.version}</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.apache.zookeeper</groupId>
+                    <artifactId>zookeeper</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.curator</groupId>
+            <artifactId>curator-recipes</artifactId>
+            <version>${curator.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.zookeeper</groupId>
+            <artifactId>zookeeper</artifactId>
+            <version>${zookeeper.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.jayway.awaitility</groupId>
+            <artifactId>awaitility</artifactId>
+            <version>${avaitility.version}</version>
+            <scope>test</scope>
+        </dependency>
+        
+        <!-- geode -->
+        <dependency>
+            <groupId>org.apache.geode</groupId>
+            <artifactId>geode-core</artifactId>
+            <version>${geode.core}</version>
+        </dependency>
+        
+        <!-- solr -->
+        <dependency>
+            <groupId>org.apache.solr</groupId>
+            <artifactId>solr-solrj</artifactId>
+            <version>${solr.solr-solrj.version}</version>
+        </dependency>
+        
+        <!-- common -->
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+        <!-- avro -->
+            <plugin>
+                <groupId>org.apache.avro</groupId>
+                <artifactId>avro-maven-plugin</artifactId>
+                <version>${avro.version}</version>
+                <executions>
+                    <execution>
+                        <id>schemas</id>
+                        <phase>generate-sources</phase>
+                        <goals>
+                            <goal>schema</goal>
+                            <goal>protocol</goal>
+                            <goal>idl-protocol</goal>
+                        </goals>
+                        <configuration>
+                            <sourceDirectory>${project.basedir}/src/main/resources/</sourceDirectory>
+                            <outputDirectory>${project.basedir}/src/main/java/</outputDirectory>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+            
+            <!-- meecrowave -->
+            <plugin>
+                <groupId>org.apache.meecrowave</groupId>
+                <artifactId>meecrowave-maven-plugin</artifactId>
+                <version>${meecrowave-maven-plugin.version}</version>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+        <avro.version>1.8.2</avro.version>
+        <slf4j.version>1.7.25</slf4j.version>
+        <beam.version>2.19.0</beam.version>
+        <assertj.version>3.9.0</assertj.version>
+        <bval.version>1.1.2</bval.version>
+        <javax.validation.validation-api.version>1.1.0.Final</javax.validation.validation-api.version>
+        <meecrowave-junit.version>1.2.0</meecrowave-junit.version>
+        <okhttp.version>3.10.0</okhttp.version>
+        <meecrowave-jpa.version>1.2.1</meecrowave-jpa.version>
+        <meecrowave-core.version>1.2.1</meecrowave-core.version>
+        <meecrowave-maven-plugin.version>1.2.1</meecrowave-maven-plugin.version>
+        <opennlp.opennlp-tools.version>1.8.4</opennlp.opennlp-tools.version>
+        <pulsar-client.version>2.1.1-incubating</pulsar-client.version>
+        <zookeeper.version>3.4.11</zookeeper.version>
+        <curator.version>4.0.1</curator.version>
+        <avaitility.version>1.7.0</avaitility.version>
+        <geode.core>1.6.0</geode.core>
+        <solr.solr-solrj.version>6.4.0</solr.solr-solrj.version>
+    </properties>
+
+</project>

apache-libraries/src/main/java/com/baeldung/avro/model/Active.java

@@ -0,0 +1,13 @@
+/**
+ * Autogenerated by Avro
+ *
+ * DO NOT EDIT DIRECTLY
+ */
+package com.baeldung.avro.model;
+@SuppressWarnings("all")
+@org.apache.avro.specific.AvroGenerated
+public enum Active {
+  YES, NO  ;
+  public static final org.apache.avro.Schema SCHEMA$ = new org.apache.avro.Schema.Parser().parse("{\"type\":\"enum\",\"name\":\"Active\",\"namespace\":\"com.baeldung.avro.model\",\"symbols\":[\"YES\",\"NO\"]}");
+  public static org.apache.avro.Schema getClassSchema() { return SCHEMA$; }
+}

apache-libraries/src/main/java/com/baeldung/avro/model/AvroHttpRequest.java

@@ -0,0 +1,491 @@
+/**
+ * Autogenerated by Avro
+ *
+ * DO NOT EDIT DIRECTLY
+ */
+package com.baeldung.avro.model;
+
+import org.apache.avro.specific.SpecificData;
+import org.apache.avro.message.BinaryMessageEncoder;
+import org.apache.avro.message.BinaryMessageDecoder;
+import org.apache.avro.message.SchemaStore;
+
+@SuppressWarnings("all")
+@org.apache.avro.specific.AvroGenerated
+public class AvroHttpRequest extends org.apache.avro.specific.SpecificRecordBase implements org.apache.avro.specific.SpecificRecord {
+  private static final long serialVersionUID = -8649010116827875312L;
+  public static final org.apache.avro.Schema SCHEMA$ = new org.apache.avro.Schema.Parser().parse("{\"type\":\"record\",\"name\":\"AvroHttpRequest\",\"namespace\":\"com.baeldung.avro.model\",\"fields\":[{\"name\":\"requestTime\",\"type\":\"long\"},{\"name\":\"clientIdentifier\",\"type\":{\"type\":\"record\",\"name\":\"ClientIdentifier\",\"fields\":[{\"name\":\"hostName\",\"type\":\"string\"},{\"name\":\"ipAddress\",\"type\":\"string\"}]}},{\"name\":\"employeeNames\",\"type\":{\"type\":\"array\",\"items\":\"string\"},\"default\":null},{\"name\":\"active\",\"type\":{\"type\":\"enum\",\"name\":\"Active\",\"symbols\":[\"YES\",\"NO\"]}}]}");
+  public static org.apache.avro.Schema getClassSchema() { return SCHEMA$; }
+
+  private static SpecificData MODEL$ = new SpecificData();
+
+  private static final BinaryMessageEncoder<AvroHttpRequest> ENCODER =
+      new BinaryMessageEncoder<AvroHttpRequest>(MODEL$, SCHEMA$);
+
+  private static final BinaryMessageDecoder<AvroHttpRequest> DECODER =
+      new BinaryMessageDecoder<AvroHttpRequest>(MODEL$, SCHEMA$);
+
+  /**
+   * Return the BinaryMessageDecoder instance used by this class.
+   */
+  public static BinaryMessageDecoder<AvroHttpRequest> getDecoder() {
+    return DECODER;
+  }
+
+  /**
+   * Create a new BinaryMessageDecoder instance for this class that uses the specified {@link SchemaStore}.
+   * @param resolver a {@link SchemaStore} used to find schemas by fingerprint
+   */
+  public static BinaryMessageDecoder<AvroHttpRequest> createDecoder(SchemaStore resolver) {
+    return new BinaryMessageDecoder<AvroHttpRequest>(MODEL$, SCHEMA$, resolver);
+  }
+
+  /** Serializes this AvroHttpRequest to a ByteBuffer. */
+  public java.nio.ByteBuffer toByteBuffer() throws java.io.IOException {
+    return ENCODER.encode(this);
+  }
+
+  /** Deserializes a AvroHttpRequest from a ByteBuffer. */
+  public static AvroHttpRequest fromByteBuffer(
+      java.nio.ByteBuffer b) throws java.io.IOException {
+    return DECODER.decode(b);
+  }
+
+  @Deprecated public long requestTime;
+  @Deprecated public com.baeldung.avro.model.ClientIdentifier clientIdentifier;
+  @Deprecated public java.util.List<java.lang.CharSequence> employeeNames;
+  @Deprecated public com.baeldung.avro.model.Active active;
+
+  /**
+   * Default constructor.  Note that this does not initialize fields
+   * to their default values from the schema.  If that is desired then
+   * one should use <code>newBuilder()</code>.
+   */
+  public AvroHttpRequest() {}
+
+  /**
+   * All-args constructor.
+   * @param requestTime The new value for requestTime
+   * @param clientIdentifier The new value for clientIdentifier
+   * @param employeeNames The new value for employeeNames
+   * @param active The new value for active
+   */
+  public AvroHttpRequest(java.lang.Long requestTime, com.baeldung.avro.model.ClientIdentifier clientIdentifier, java.util.List<java.lang.CharSequence> employeeNames, com.baeldung.avro.model.Active active) {
+    this.requestTime = requestTime;
+    this.clientIdentifier = clientIdentifier;
+    this.employeeNames = employeeNames;
+    this.active = active;
+  }
+
+  public org.apache.avro.Schema getSchema() { return SCHEMA$; }
+  // Used by DatumWriter.  Applications should not call.
+  public java.lang.Object get(int field$) {
+    switch (field$) {
+    case 0: return requestTime;
+    case 1: return clientIdentifier;
+    case 2: return employeeNames;
+    case 3: return active;
+    default: throw new org.apache.avro.AvroRuntimeException("Bad index");
+    }
+  }
+
+  // Used by DatumReader.  Applications should not call.
+  @SuppressWarnings(value="unchecked")
+  public void put(int field$, java.lang.Object value$) {
+    switch (field$) {
+    case 0: requestTime = (java.lang.Long)value$; break;
+    case 1: clientIdentifier = (com.baeldung.avro.model.ClientIdentifier)value$; break;
+    case 2: employeeNames = (java.util.List<java.lang.CharSequence>)value$; break;
+    case 3: active = (com.baeldung.avro.model.Active)value$; break;
+    default: throw new org.apache.avro.AvroRuntimeException("Bad index");
+    }
+  }
+
+  /**
+   * Gets the value of the 'requestTime' field.
+   * @return The value of the 'requestTime' field.
+   */
+  public java.lang.Long getRequestTime() {
+    return requestTime;
+  }
+
+  /**
+   * Sets the value of the 'requestTime' field.
+   * @param value the value to set.
+   */
+  public void setRequestTime(java.lang.Long value) {
+    this.requestTime = value;
+  }
+
+  /**
+   * Gets the value of the 'clientIdentifier' field.
+   * @return The value of the 'clientIdentifier' field.
+   */
+  public com.baeldung.avro.model.ClientIdentifier getClientIdentifier() {
+    return clientIdentifier;
+  }
+
+  /**
+   * Sets the value of the 'clientIdentifier' field.
+   * @param value the value to set.
+   */
+  public void setClientIdentifier(com.baeldung.avro.model.ClientIdentifier value) {
+    this.clientIdentifier = value;
+  }
+
+  /**
+   * Gets the value of the 'employeeNames' field.
+   * @return The value of the 'employeeNames' field.
+   */
+  public java.util.List<java.lang.CharSequence> getEmployeeNames() {
+    return employeeNames;
+  }
+
+  /**
+   * Sets the value of the 'employeeNames' field.
+   * @param value the value to set.
+   */
+  public void setEmployeeNames(java.util.List<java.lang.CharSequence> value) {
+    this.employeeNames = value;
+  }
+
+  /**
+   * Gets the value of the 'active' field.
+   * @return The value of the 'active' field.
+   */
+  public com.baeldung.avro.model.Active getActive() {
+    return active;
+  }
+
+  /**
+   * Sets the value of the 'active' field.
+   * @param value the value to set.
+   */
+  public void setActive(com.baeldung.avro.model.Active value) {
+    this.active = value;
+  }
+
+  /**
+   * Creates a new AvroHttpRequest RecordBuilder.
+   * @return A new AvroHttpRequest RecordBuilder
+   */
+  public static com.baeldung.avro.model.AvroHttpRequest.Builder newBuilder() {
+    return new com.baeldung.avro.model.AvroHttpRequest.Builder();
+  }
+
+  /**
+   * Creates a new AvroHttpRequest RecordBuilder by copying an existing Builder.
+   * @param other The existing builder to copy.
+   * @return A new AvroHttpRequest RecordBuilder
+   */
+  public static com.baeldung.avro.model.AvroHttpRequest.Builder newBuilder(com.baeldung.avro.model.AvroHttpRequest.Builder other) {
+    return new com.baeldung.avro.model.AvroHttpRequest.Builder(other);
+  }
+
+  /**
+   * Creates a new AvroHttpRequest RecordBuilder by copying an existing AvroHttpRequest instance.
+   * @param other The existing instance to copy.
+   * @return A new AvroHttpRequest RecordBuilder
+   */
+  public static com.baeldung.avro.model.AvroHttpRequest.Builder newBuilder(com.baeldung.avro.model.AvroHttpRequest other) {
+    return new com.baeldung.avro.model.AvroHttpRequest.Builder(other);
+  }
+
+  /**
+   * RecordBuilder for AvroHttpRequest instances.
+   */
+  public static class Builder extends org.apache.avro.specific.SpecificRecordBuilderBase<AvroHttpRequest>
+    implements org.apache.avro.data.RecordBuilder<AvroHttpRequest> {
+
+    private long requestTime;
+    private com.baeldung.avro.model.ClientIdentifier clientIdentifier;
+    private com.baeldung.avro.model.ClientIdentifier.Builder clientIdentifierBuilder;
+    private java.util.List<java.lang.CharSequence> employeeNames;
+    private com.baeldung.avro.model.Active active;
+
+    /** Creates a new Builder */
+    private Builder() {
+      super(SCHEMA$);
+    }
+
+    /**
+     * Creates a Builder by copying an existing Builder.
+     * @param other The existing Builder to copy.
+     */
+    private Builder(com.baeldung.avro.model.AvroHttpRequest.Builder other) {
+      super(other);
+      if (isValidValue(fields()[0], other.requestTime)) {
+        this.requestTime = data().deepCopy(fields()[0].schema(), other.requestTime);
+        fieldSetFlags()[0] = true;
+      }
+      if (isValidValue(fields()[1], other.clientIdentifier)) {
+        this.clientIdentifier = data().deepCopy(fields()[1].schema(), other.clientIdentifier);
+        fieldSetFlags()[1] = true;
+      }
+      if (other.hasClientIdentifierBuilder()) {
+        this.clientIdentifierBuilder = com.baeldung.avro.model.ClientIdentifier.newBuilder(other.getClientIdentifierBuilder());
+      }
+      if (isValidValue(fields()[2], other.employeeNames)) {
+        this.employeeNames = data().deepCopy(fields()[2].schema(), other.employeeNames);
+        fieldSetFlags()[2] = true;
+      }
+      if (isValidValue(fields()[3], other.active)) {
+        this.active = data().deepCopy(fields()[3].schema(), other.active);
+        fieldSetFlags()[3] = true;
+      }
+    }
+
+    /**
+     * Creates a Builder by copying an existing AvroHttpRequest instance
+     * @param other The existing instance to copy.
+     */
+    private Builder(com.baeldung.avro.model.AvroHttpRequest other) {
+            super(SCHEMA$);
+      if (isValidValue(fields()[0], other.requestTime)) {
+        this.requestTime = data().deepCopy(fields()[0].schema(), other.requestTime);
+        fieldSetFlags()[0] = true;
+      }
+      if (isValidValue(fields()[1], other.clientIdentifier)) {
+        this.clientIdentifier = data().deepCopy(fields()[1].schema(), other.clientIdentifier);
+        fieldSetFlags()[1] = true;
+      }
+      this.clientIdentifierBuilder = null;
+      if (isValidValue(fields()[2], other.employeeNames)) {
+        this.employeeNames = data().deepCopy(fields()[2].schema(), other.employeeNames);
+        fieldSetFlags()[2] = true;
+      }
+      if (isValidValue(fields()[3], other.active)) {
+        this.active = data().deepCopy(fields()[3].schema(), other.active);
+        fieldSetFlags()[3] = true;
+      }
+    }
+
+    /**
+      * Gets the value of the 'requestTime' field.
+      * @return The value.
+      */
+    public java.lang.Long getRequestTime() {
+      return requestTime;
+    }
+
+    /**
+      * Sets the value of the 'requestTime' field.
+      * @param value The value of 'requestTime'.
+      * @return This builder.
+      */
+    public com.baeldung.avro.model.AvroHttpRequest.Builder setRequestTime(long value) {
+      validate(fields()[0], value);
+      this.requestTime = value;
+      fieldSetFlags()[0] = true;
+      return this;
+    }
+
+    /**
+      * Checks whether the 'requestTime' field has been set.
+      * @return True if the 'requestTime' field has been set, false otherwise.
+      */
+    public boolean hasRequestTime() {
+      return fieldSetFlags()[0];
+    }
+
+
+    /**
+      * Clears the value of the 'requestTime' field.
+      * @return This builder.
+      */
+    public com.baeldung.avro.model.AvroHttpRequest.Builder clearRequestTime() {
+      fieldSetFlags()[0] = false;
+      return this;
+    }
+
+    /**
+      * Gets the value of the 'clientIdentifier' field.
+      * @return The value.
+      */
+    public com.baeldung.avro.model.ClientIdentifier getClientIdentifier() {
+      return clientIdentifier;
+    }
+
+    /**
+      * Sets the value of the 'clientIdentifier' field.
+      * @param value The value of 'clientIdentifier'.
+      * @return This builder.
+      */
+    public com.baeldung.avro.model.AvroHttpRequest.Builder setClientIdentifier(com.baeldung.avro.model.ClientIdentifier value) {
+      validate(fields()[1], value);
+      this.clientIdentifierBuilder = null;
+      this.clientIdentifier = value;
+      fieldSetFlags()[1] = true;
+      return this;
+    }
+
+    /**
+      * Checks whether the 'clientIdentifier' field has been set.
+      * @return True if the 'clientIdentifier' field has been set, false otherwise.
+      */
+    public boolean hasClientIdentifier() {
+      return fieldSetFlags()[1];
+    }
+
+    /**
+     * Gets the Builder instance for the 'clientIdentifier' field and creates one if it doesn't exist yet.
+     * @return This builder.
+     */
+    public com.baeldung.avro.model.ClientIdentifier.Builder getClientIdentifierBuilder() {
+      if (clientIdentifierBuilder == null) {
+        if (hasClientIdentifier()) {
+          setClientIdentifierBuilder(com.baeldung.avro.model.ClientIdentifier.newBuilder(clientIdentifier));
+        } else {
+          setClientIdentifierBuilder(com.baeldung.avro.model.ClientIdentifier.newBuilder());
+        }
+      }
+      return clientIdentifierBuilder;
+    }
+
+    /**
+     * Sets the Builder instance for the 'clientIdentifier' field
+     * @param value The builder instance that must be set.
+     * @return This builder.
+     */
+    public com.baeldung.avro.model.AvroHttpRequest.Builder setClientIdentifierBuilder(com.baeldung.avro.model.ClientIdentifier.Builder value) {
+      clearClientIdentifier();
+      clientIdentifierBuilder = value;
+      return this;
+    }
+
+    /**
+     * Checks whether the 'clientIdentifier' field has an active Builder instance
+     * @return True if the 'clientIdentifier' field has an active Builder instance
+     */
+    public boolean hasClientIdentifierBuilder() {
+      return clientIdentifierBuilder != null;
+    }
+
+    /**
+      * Clears the value of the 'clientIdentifier' field.
+      * @return This builder.
+      */
+    public com.baeldung.avro.model.AvroHttpRequest.Builder clearClientIdentifier() {
+      clientIdentifier = null;
+      clientIdentifierBuilder = null;
+      fieldSetFlags()[1] = false;
+      return this;
+    }
+
+    /**
+      * Gets the value of the 'employeeNames' field.
+      * @return The value.
+      */
+    public java.util.List<java.lang.CharSequence> getEmployeeNames() {
+      return employeeNames;
+    }
+
+    /**
+      * Sets the value of the 'employeeNames' field.
+      * @param value The value of 'employeeNames'.
+      * @return This builder.
+      */
+    public com.baeldung.avro.model.AvroHttpRequest.Builder setEmployeeNames(java.util.List<java.lang.CharSequence> value) {
+      validate(fields()[2], value);
+      this.employeeNames = value;
+      fieldSetFlags()[2] = true;
+      return this;
+    }
+
+    /**
+      * Checks whether the 'employeeNames' field has been set.
+      * @return True if the 'employeeNames' field has been set, false otherwise.
+      */
+    public boolean hasEmployeeNames() {
+      return fieldSetFlags()[2];
+    }
+
+
+    /**
+      * Clears the value of the 'employeeNames' field.
+      * @return This builder.
+      */
+    public com.baeldung.avro.model.AvroHttpRequest.Builder clearEmployeeNames() {
+      employeeNames = null;
+      fieldSetFlags()[2] = false;
+      return this;
+    }
+
+    /**
+      * Gets the value of the 'active' field.
+      * @return The value.
+      */
+    public com.baeldung.avro.model.Active getActive() {
+      return active;
+    }
+
+    /**
+      * Sets the value of the 'active' field.
+      * @param value The value of 'active'.
+      * @return This builder.
+      */
+    public com.baeldung.avro.model.AvroHttpRequest.Builder setActive(com.baeldung.avro.model.Active value) {
+      validate(fields()[3], value);
+      this.active = value;
+      fieldSetFlags()[3] = true;
+      return this;
+    }
+
+    /**
+      * Checks whether the 'active' field has been set.
+      * @return True if the 'active' field has been set, false otherwise.
+      */
+    public boolean hasActive() {
+      return fieldSetFlags()[3];
+    }
+
+
+    /**
+      * Clears the value of the 'active' field.
+      * @return This builder.
+      */
+    public com.baeldung.avro.model.AvroHttpRequest.Builder clearActive() {
+      active = null;
+      fieldSetFlags()[3] = false;
+      return this;
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public AvroHttpRequest build() {
+      try {
+        AvroHttpRequest record = new AvroHttpRequest();
+        record.requestTime = fieldSetFlags()[0] ? this.requestTime : (java.lang.Long) defaultValue(fields()[0]);
+        if (clientIdentifierBuilder != null) {
+          record.clientIdentifier = this.clientIdentifierBuilder.build();
+        } else {
+          record.clientIdentifier = fieldSetFlags()[1] ? this.clientIdentifier : (com.baeldung.avro.model.ClientIdentifier) defaultValue(fields()[1]);
+        }
+        record.employeeNames = fieldSetFlags()[2] ? this.employeeNames : (java.util.List<java.lang.CharSequence>) defaultValue(fields()[2]);
+        record.active = fieldSetFlags()[3] ? this.active : (com.baeldung.avro.model.Active) defaultValue(fields()[3]);
+        return record;
+      } catch (java.lang.Exception e) {
+        throw new org.apache.avro.AvroRuntimeException(e);
+      }
+    }
+  }
+
+  @SuppressWarnings("unchecked")
+  private static final org.apache.avro.io.DatumWriter<AvroHttpRequest>
+    WRITER$ = (org.apache.avro.io.DatumWriter<AvroHttpRequest>)MODEL$.createDatumWriter(SCHEMA$);
+
+  @Override public void writeExternal(java.io.ObjectOutput out)
+    throws java.io.IOException {
+    WRITER$.write(this, SpecificData.getEncoder(out));
+  }
+
+  @SuppressWarnings("unchecked")
+  private static final org.apache.avro.io.DatumReader<AvroHttpRequest>
+    READER$ = (org.apache.avro.io.DatumReader<AvroHttpRequest>)MODEL$.createDatumReader(SCHEMA$);
+
+  @Override public void readExternal(java.io.ObjectInput in)
+    throws java.io.IOException {
+    READER$.read(this, SpecificData.getDecoder(in));
+  }
+
+}

apache-libraries/src/main/java/com/baeldung/avro/model/ClientIdentifier.java

@@ -0,0 +1,308 @@
+/**
+ * Autogenerated by Avro
+ *
+ * DO NOT EDIT DIRECTLY
+ */
+package com.baeldung.avro.model;
+
+import org.apache.avro.specific.SpecificData;
+import org.apache.avro.message.BinaryMessageEncoder;
+import org.apache.avro.message.BinaryMessageDecoder;
+import org.apache.avro.message.SchemaStore;
+
+@SuppressWarnings("all")
+@org.apache.avro.specific.AvroGenerated
+public class ClientIdentifier extends org.apache.avro.specific.SpecificRecordBase implements org.apache.avro.specific.SpecificRecord {
+  private static final long serialVersionUID = 8754570983127295424L;
+  public static final org.apache.avro.Schema SCHEMA$ = new org.apache.avro.Schema.Parser().parse("{\"type\":\"record\",\"name\":\"ClientIdentifier\",\"namespace\":\"com.baeldung.avro.model\",\"fields\":[{\"name\":\"hostName\",\"type\":\"string\"},{\"name\":\"ipAddress\",\"type\":\"string\"}]}");
+  public static org.apache.avro.Schema getClassSchema() { return SCHEMA$; }
+
+  private static SpecificData MODEL$ = new SpecificData();
+
+  private static final BinaryMessageEncoder<ClientIdentifier> ENCODER =
+      new BinaryMessageEncoder<ClientIdentifier>(MODEL$, SCHEMA$);
+
+  private static final BinaryMessageDecoder<ClientIdentifier> DECODER =
+      new BinaryMessageDecoder<ClientIdentifier>(MODEL$, SCHEMA$);
+
+  /**
+   * Return the BinaryMessageDecoder instance used by this class.
+   */
+  public static BinaryMessageDecoder<ClientIdentifier> getDecoder() {
+    return DECODER;
+  }
+
+  /**
+   * Create a new BinaryMessageDecoder instance for this class that uses the specified {@link SchemaStore}.
+   * @param resolver a {@link SchemaStore} used to find schemas by fingerprint
+   */
+  public static BinaryMessageDecoder<ClientIdentifier> createDecoder(SchemaStore resolver) {
+    return new BinaryMessageDecoder<ClientIdentifier>(MODEL$, SCHEMA$, resolver);
+  }
+
+  /** Serializes this ClientIdentifier to a ByteBuffer. */
+  public java.nio.ByteBuffer toByteBuffer() throws java.io.IOException {
+    return ENCODER.encode(this);
+  }
+
+  /** Deserializes a ClientIdentifier from a ByteBuffer. */
+  public static ClientIdentifier fromByteBuffer(
+      java.nio.ByteBuffer b) throws java.io.IOException {
+    return DECODER.decode(b);
+  }
+
+  @Deprecated public java.lang.CharSequence hostName;
+  @Deprecated public java.lang.CharSequence ipAddress;
+
+  /**
+   * Default constructor.  Note that this does not initialize fields
+   * to their default values from the schema.  If that is desired then
+   * one should use <code>newBuilder()</code>.
+   */
+  public ClientIdentifier() {}
+
+  /**
+   * All-args constructor.
+   * @param hostName The new value for hostName
+   * @param ipAddress The new value for ipAddress
+   */
+  public ClientIdentifier(java.lang.CharSequence hostName, java.lang.CharSequence ipAddress) {
+    this.hostName = hostName;
+    this.ipAddress = ipAddress;
+  }
+
+  public org.apache.avro.Schema getSchema() { return SCHEMA$; }
+  // Used by DatumWriter.  Applications should not call.
+  public java.lang.Object get(int field$) {
+    switch (field$) {
+    case 0: return hostName;
+    case 1: return ipAddress;
+    default: throw new org.apache.avro.AvroRuntimeException("Bad index");
+    }
+  }
+
+  // Used by DatumReader.  Applications should not call.
+  @SuppressWarnings(value="unchecked")
+  public void put(int field$, java.lang.Object value$) {
+    switch (field$) {
+    case 0: hostName = (java.lang.CharSequence)value$; break;
+    case 1: ipAddress = (java.lang.CharSequence)value$; break;
+    default: throw new org.apache.avro.AvroRuntimeException("Bad index");
+    }
+  }
+
+  /**
+   * Gets the value of the 'hostName' field.
+   * @return The value of the 'hostName' field.
+   */
+  public java.lang.CharSequence getHostName() {
+    return hostName;
+  }
+
+  /**
+   * Sets the value of the 'hostName' field.
+   * @param value the value to set.
+   */
+  public void setHostName(java.lang.CharSequence value) {
+    this.hostName = value;
+  }
+
+  /**
+   * Gets the value of the 'ipAddress' field.
+   * @return The value of the 'ipAddress' field.
+   */
+  public java.lang.CharSequence getIpAddress() {
+    return ipAddress;
+  }
+
+  /**
+   * Sets the value of the 'ipAddress' field.
+   * @param value the value to set.
+   */
+  public void setIpAddress(java.lang.CharSequence value) {
+    this.ipAddress = value;
+  }
+
+  /**
+   * Creates a new ClientIdentifier RecordBuilder.
+   * @return A new ClientIdentifier RecordBuilder
+   */
+  public static com.baeldung.avro.model.ClientIdentifier.Builder newBuilder() {
+    return new com.baeldung.avro.model.ClientIdentifier.Builder();
+  }
+
+  /**
+   * Creates a new ClientIdentifier RecordBuilder by copying an existing Builder.
+   * @param other The existing builder to copy.
+   * @return A new ClientIdentifier RecordBuilder
+   */
+  public static com.baeldung.avro.model.ClientIdentifier.Builder newBuilder(com.baeldung.avro.model.ClientIdentifier.Builder other) {
+    return new com.baeldung.avro.model.ClientIdentifier.Builder(other);
+  }
+
+  /**
+   * Creates a new ClientIdentifier RecordBuilder by copying an existing ClientIdentifier instance.
+   * @param other The existing instance to copy.
+   * @return A new ClientIdentifier RecordBuilder
+   */
+  public static com.baeldung.avro.model.ClientIdentifier.Builder newBuilder(com.baeldung.avro.model.ClientIdentifier other) {
+    return new com.baeldung.avro.model.ClientIdentifier.Builder(other);
+  }
+
+  /**
+   * RecordBuilder for ClientIdentifier instances.
+   */
+  public static class Builder extends org.apache.avro.specific.SpecificRecordBuilderBase<ClientIdentifier>
+    implements org.apache.avro.data.RecordBuilder<ClientIdentifier> {
+
+    private java.lang.CharSequence hostName;
+    private java.lang.CharSequence ipAddress;
+
+    /** Creates a new Builder */
+    private Builder() {
+      super(SCHEMA$);
+    }
+
+    /**
+     * Creates a Builder by copying an existing Builder.
+     * @param other The existing Builder to copy.
+     */
+    private Builder(com.baeldung.avro.model.ClientIdentifier.Builder other) {
+      super(other);
+      if (isValidValue(fields()[0], other.hostName)) {
+        this.hostName = data().deepCopy(fields()[0].schema(), other.hostName);
+        fieldSetFlags()[0] = true;
+      }
+      if (isValidValue(fields()[1], other.ipAddress)) {
+        this.ipAddress = data().deepCopy(fields()[1].schema(), other.ipAddress);
+        fieldSetFlags()[1] = true;
+      }
+    }
+
+    /**
+     * Creates a Builder by copying an existing ClientIdentifier instance
+     * @param other The existing instance to copy.
+     */
+    private Builder(com.baeldung.avro.model.ClientIdentifier other) {
+            super(SCHEMA$);
+      if (isValidValue(fields()[0], other.hostName)) {
+        this.hostName = data().deepCopy(fields()[0].schema(), other.hostName);
+        fieldSetFlags()[0] = true;
+      }
+      if (isValidValue(fields()[1], other.ipAddress)) {
+        this.ipAddress = data().deepCopy(fields()[1].schema(), other.ipAddress);
+        fieldSetFlags()[1] = true;
+      }
+    }
+
+    /**
+      * Gets the value of the 'hostName' field.
+      * @return The value.
+      */
+    public java.lang.CharSequence getHostName() {
+      return hostName;
+    }
+
+    /**
+      * Sets the value of the 'hostName' field.
+      * @param value The value of 'hostName'.
+      * @return This builder.
+      */
+    public com.baeldung.avro.model.ClientIdentifier.Builder setHostName(java.lang.CharSequence value) {
+      validate(fields()[0], value);
+      this.hostName = value;
+      fieldSetFlags()[0] = true;
+      return this;
+    }
+
+    /**
+      * Checks whether the 'hostName' field has been set.
+      * @return True if the 'hostName' field has been set, false otherwise.
+      */
+    public boolean hasHostName() {
+      return fieldSetFlags()[0];
+    }
+
+
+    /**
+      * Clears the value of the 'hostName' field.
+      * @return This builder.
+      */
+    public com.baeldung.avro.model.ClientIdentifier.Builder clearHostName() {
+      hostName = null;
+      fieldSetFlags()[0] = false;
+      return this;
+    }
+
+    /**
+      * Gets the value of the 'ipAddress' field.
+      * @return The value.
+      */
+    public java.lang.CharSequence getIpAddress() {
+      return ipAddress;
+    }
+
+    /**
+      * Sets the value of the 'ipAddress' field.
+      * @param value The value of 'ipAddress'.
+      * @return This builder.
+      */
+    public com.baeldung.avro.model.ClientIdentifier.Builder setIpAddress(java.lang.CharSequence value) {
+      validate(fields()[1], value);
+      this.ipAddress = value;
+      fieldSetFlags()[1] = true;
+      return this;
+    }
+
+    /**
+      * Checks whether the 'ipAddress' field has been set.
+      * @return True if the 'ipAddress' field has been set, false otherwise.
+      */
+    public boolean hasIpAddress() {
+      return fieldSetFlags()[1];
+    }
+
+
+    /**
+      * Clears the value of the 'ipAddress' field.
+      * @return This builder.
+      */
+    public com.baeldung.avro.model.ClientIdentifier.Builder clearIpAddress() {
+      ipAddress = null;
+      fieldSetFlags()[1] = false;
+      return this;
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public ClientIdentifier build() {
+      try {
+        ClientIdentifier record = new ClientIdentifier();
+        record.hostName = fieldSetFlags()[0] ? this.hostName : (java.lang.CharSequence) defaultValue(fields()[0]);
+        record.ipAddress = fieldSetFlags()[1] ? this.ipAddress : (java.lang.CharSequence) defaultValue(fields()[1]);
+        return record;
+      } catch (java.lang.Exception e) {
+        throw new org.apache.avro.AvroRuntimeException(e);
+      }
+    }
+  }
+
+  @SuppressWarnings("unchecked")
+  private static final org.apache.avro.io.DatumWriter<ClientIdentifier>
+    WRITER$ = (org.apache.avro.io.DatumWriter<ClientIdentifier>)MODEL$.createDatumWriter(SCHEMA$);
+
+  @Override public void writeExternal(java.io.ObjectOutput out)
+    throws java.io.IOException {
+    WRITER$.write(this, SpecificData.getEncoder(out));
+  }
+
+  @SuppressWarnings("unchecked")
+  private static final org.apache.avro.io.DatumReader<ClientIdentifier>
+    READER$ = (org.apache.avro.io.DatumReader<ClientIdentifier>)MODEL$.createDatumReader(SCHEMA$);
+
+  @Override public void readExternal(java.io.ObjectInput in)
+    throws java.io.IOException {
+    READER$.read(this, SpecificData.getDecoder(in));
+  }
+
+}

apache-libraries/src/main/java/com/baeldung/bval/model/User.java

@@ -1,4 +1,4 @@
-package com.baeldung.model;
+package com.baeldung.bval.model;
 
 import java.io.File;
 
@@ -13,7 +13,7 @@ import org.apache.bval.extras.constraints.creditcard.Visa;
 import org.apache.bval.extras.constraints.file.Directory;
 import org.apache.bval.extras.constraints.net.InetAddress;
 
-import com.baeldung.validation.Password;
+import com.baeldung.bval.validation.Password;
 
 public class User {
     @NotNull

apache-libraries/src/main/java/com/baeldung/bval/validation/Password.java

@@ -1,4 +1,4 @@
-package com.baeldung.validation;
+package com.baeldung.bval.validation;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;

apache-libraries/src/main/java/com/baeldung/bval/validation/PasswordValidator.java

@@ -1,4 +1,4 @@
-package com.baeldung.validation;
+package com.baeldung.bval.validation;
 
 import javax.validation.ConstraintValidator;
 import javax.validation.ConstraintValidatorContext;

apache-libraries/src/main/java/com/baeldung/pulsar/ConsumerUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.pulsar;
 
 import java.io.IOException;
 

apache-libraries/src/main/java/com/baeldung/pulsar/ProducerUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.pulsar;
 
 import org.apache.pulsar.client.api.CompressionType;
 import org.apache.pulsar.client.api.Message;

apache-libraries/src/main/java/com/baeldung/pulsar/subscriptions/ExclusiveSubscriptionUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.subscriptions;
+package com.baeldung.pulsar.subscriptions;
 
 import org.apache.pulsar.client.api.ConsumerBuilder;
 import org.apache.pulsar.client.api.Message;

apache-libraries/src/main/java/com/baeldung/pulsar/subscriptions/FailoverSubscriptionUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.subscriptions;
+package com.baeldung.pulsar.subscriptions;
 
 import org.apache.pulsar.client.api.Consumer;
 import org.apache.pulsar.client.api.ConsumerBuilder;

apache-libraries/src/test/java/com/baeldung/bval/validation/ValidationIntegrationTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.validation;
+package com.baeldung.bval.validation;
 
 import java.io.File;
 import java.util.Set;
@@ -13,9 +13,9 @@ import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Test;
 
-import static org.junit.Assert.*;
+import com.baeldung.bval.model.User;
 
-import com.baeldung.model.User;
+import static org.junit.Assert.*;
 
 public class ValidationIntegrationTest {
     private static ValidatorFactory validatorFactory;

apache-meecrowave/README.md

@@ -1,7 +0,0 @@
-## Apache Meecrowave
-
-This module contains articles about Apache Meecrowave
-
-### Relevant Articles: 
-
-- [Building a Microservice with Apache Meecrowave](https://www.baeldung.com/apache-meecrowave)

apache-meecrowave/pom.xml

@@ -1,65 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project
-    xmlns="http://maven.apache.org/POM/4.0.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-    <artifactId>apache-meecrowave</artifactId>
-    <version>0.0.1</version>
-    <name>apache-meecrowave</name>
-    <description>A sample REST API application with Meecrowave</description>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-    </parent>
-
-    <dependencies>
-        <!-- https://mvnrepository.com/artifact/org.apache.meecrowave/meecrowave-core -->
-        <dependency>
-            <groupId>org.apache.meecrowave</groupId>
-            <artifactId>meecrowave-core</artifactId>
-            <version>${meecrowave-core.version}</version>
-        </dependency>
-        <!-- https://mvnrepository.com/artifact/org.apache.meecrowave/meecrowave-jpa -->
-        <dependency>
-            <groupId>org.apache.meecrowave</groupId>
-            <artifactId>meecrowave-jpa</artifactId>
-            <version>${meecrowave-jpa.version}</version>
-        </dependency>
-
-        <dependency>
-            <groupId>com.squareup.okhttp3</groupId>
-            <artifactId>okhttp</artifactId>
-            <version>${okhttp.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.meecrowave</groupId>
-            <artifactId>meecrowave-junit</artifactId>
-            <version>${meecrowave-junit.version}</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.meecrowave</groupId>
-                <artifactId>meecrowave-maven-plugin</artifactId>
-                <version>${meecrowave-maven-plugin.version}</version>
-            </plugin>
-        </plugins>
-    </build>
-
-    <properties>
-        <maven.compiler.source>1.8</maven.compiler.source>
-        <maven.compiler.target>1.8</maven.compiler.target>
-        <meecrowave-junit.version>1.2.0</meecrowave-junit.version>
-        <okhttp.version>3.10.0</okhttp.version>
-        <meecrowave-jpa.version>1.2.1</meecrowave-jpa.version>
-        <meecrowave-core.version>1.2.1</meecrowave-core.version>
-        <meecrowave-maven-plugin.version>1.2.1</meecrowave-maven-plugin.version>
-    </properties>
-
-</project>

apache-opennlp/README.md

@@ -1,7 +0,0 @@
-## Apache OpenNLP
-
-This module contains articles about Apache OpenNLP
-
-### Relevant Articles
-
-- [Intro to Apache OpenNLP](https://www.baeldung.com/apache-open-nlp)

apache-opennlp/pom.xml

@@ -1,37 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project
-    xmlns="http://maven.apache.org/POM/4.0.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-    <artifactId>apache-opennlp</artifactId>
-    <version>1.0-SNAPSHOT</version>
-    <name>apache-opennlp</name>
-    <packaging>jar</packaging>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-    </parent>
-
-    <dependencies>
-        <dependency>
-            <groupId>org.apache.opennlp</groupId>
-            <artifactId>opennlp-tools</artifactId>
-            <version>${org.apache.opennlp.opennlp-tools.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>org.assertj</groupId>
-            <artifactId>assertj-core</artifactId>
-            <version>${org.assertj.version}</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
-    <properties>
-        <org.assertj.version>3.9.0</org.assertj.version>
-        <org.apache.opennlp.opennlp-tools.version>1.8.4</org.apache.opennlp.opennlp-tools.version>
-    </properties>
-
-</project>

apache-pulsar/.gitignore

@@ -1,8 +0,0 @@
-.classpath
-.project
-.settings
-target
-.idea
-*.iml
-.gradle/
-build/

apache-pulsar/README.md

@@ -1,7 +0,0 @@
-## Apache Pulsar
-
-This module contains articles about Apache Pulsar
-
-### Relevant Articles: 
-
-- [Introduction to Apache Pulsar](https://www.baeldung.com/apache-pulsar)

apache-pulsar/pom.xml

@@ -1,32 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
-    xmlns="http://maven.apache.org/POM/4.0.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
-    <modelVersion>4.0.0</modelVersion>
-    <groupId>com.baeldung.pulsar</groupId>
-    <artifactId>apache-pulsar</artifactId>
-    <version>0.0.1</version>
-    <name>apache-pulsar</name>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-        <relativePath>..</relativePath>
-    </parent>
-
-    <dependencies>
-        <dependency>
-            <groupId>org.apache.pulsar</groupId>
-            <artifactId>pulsar-client</artifactId>
-            <version>${pulsar-client.version}</version>
-            <scope>compile</scope>
-        </dependency>
-    </dependencies>
-
-    <properties>
-        <pulsar-client.version>2.1.1-incubating</pulsar-client.version>
-    </properties>
-
-</project>

apache-shiro/README.md

@@ -6,4 +6,4 @@ This module contains articles about Apache Shiro
 
 - [Introduction to Apache Shiro](https://www.baeldung.com/apache-shiro)
 - [Permissions-Based Access Control with Apache Shiro](https://www.baeldung.com/apache-shiro-access-control)
-
+- [Spring Security vs Apache Shiro](https://www.baeldung.com/spring-security-vs-apache-shiro)

apache-shiro/pom.xml

@@ -39,10 +39,19 @@
             <artifactId>jcl-over-slf4j</artifactId>
             <scope>runtime</scope>
         </dependency>
+        <!-- spring-sec -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-security</artifactId>
+        </dependency>
     </dependencies>
 
     <properties>
-        <apache-shiro-core-version>1.4.0</apache-shiro-core-version>
+        <apache-shiro-core-version>1.5.3</apache-shiro-core-version>
         <log4j-version>1.2.17</log4j-version>
     </properties>
 

apache-shiro/src/main/java/com/baeldung/comparison/shiro/CustomRealm.java

@@ -0,0 +1,96 @@
+package com.baeldung.comparison.shiro;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.shiro.authc.AuthenticationException;
+import org.apache.shiro.authc.AuthenticationInfo;
+import org.apache.shiro.authc.AuthenticationToken;
+import org.apache.shiro.authc.SimpleAuthenticationInfo;
+import org.apache.shiro.authc.UnknownAccountException;
+import org.apache.shiro.authc.UsernamePasswordToken;
+import org.apache.shiro.authz.AuthorizationInfo;
+import org.apache.shiro.authz.SimpleAuthorizationInfo;
+import org.apache.shiro.realm.jdbc.JdbcRealm;
+import org.apache.shiro.subject.PrincipalCollection;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class CustomRealm extends JdbcRealm {
+    
+    private Logger logger = LoggerFactory.getLogger(CustomRealm.class);
+
+    private Map<String, String> credentials = new HashMap<>();
+    private Map<String, Set<String>> roles = new HashMap<>();
+    private Map<String, Set<String>> permissions = new HashMap<>();
+
+    {
+        credentials.put("Tom", "password");
+        credentials.put("Jerry", "password");
+
+        roles.put("Jerry", new HashSet<>(Arrays.asList("ADMIN")));
+        roles.put("Tom", new HashSet<>(Arrays.asList("USER")));
+
+        permissions.put("ADMIN", new HashSet<>(Arrays.asList("READ", "WRITE")));
+        permissions.put("USER", new HashSet<>(Arrays.asList("READ")));
+    }
+
+    @Override
+    protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken token) throws AuthenticationException {
+
+        UsernamePasswordToken userToken = (UsernamePasswordToken) token;
+
+        if (userToken.getUsername() == null || userToken.getUsername()
+            .isEmpty() || !credentials.containsKey(userToken.getUsername())) {
+            throw new UnknownAccountException("User doesn't exist");
+        }
+
+        return new SimpleAuthenticationInfo(userToken.getUsername(), credentials.get(userToken.getUsername()), getName());
+    }
+
+    @Override
+    protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principals) {
+        Set<String> roles = new HashSet<>();
+        Set<String> permissions = new HashSet<>();
+
+        for (Object user : principals) {
+            try {
+                roles.addAll(getRoleNamesForUser(null, (String) user));
+                permissions.addAll(getPermissions(null, null, roles));
+            } catch (SQLException e) {
+                logger.error(e.getMessage());
+            }
+        }
+        SimpleAuthorizationInfo authInfo = new SimpleAuthorizationInfo(roles);
+        authInfo.setStringPermissions(permissions);
+        return authInfo;
+    }
+
+    @Override
+    protected Set<String> getRoleNamesForUser(Connection conn, String username) throws SQLException {
+        if (!roles.containsKey(username)) {
+            throw new SQLException("User doesn't exist");
+        }
+        return roles.get(username);
+    }
+
+    @Override
+    protected Set<String> getPermissions(Connection conn, String username, Collection<String> roles) throws SQLException {
+        Set<String> userPermissions = new HashSet<>();
+
+        for (String role : roles) {
+            if (!permissions.containsKey(role)) {
+                throw new SQLException("Role doesn't exist");
+            }
+            userPermissions.addAll(permissions.get(role));
+        }
+        return userPermissions;
+    }
+
+}

apache-shiro/src/main/java/com/baeldung/comparison/shiro/ShiroApplication.java

@@ -0,0 +1,33 @@
+package com.baeldung.comparison.shiro;
+
+import org.apache.shiro.realm.Realm;
+import org.apache.shiro.spring.web.config.DefaultShiroFilterChainDefinition;
+import org.apache.shiro.spring.web.config.ShiroFilterChainDefinition;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration;
+import org.springframework.context.annotation.Bean;
+
+@SpringBootApplication(exclude = SecurityAutoConfiguration.class)
+public class ShiroApplication {
+
+    public static void main(String... args) {
+        SpringApplication.run(ShiroApplication.class, args);
+    }
+
+    @Bean
+    public Realm customRealm() {
+        return new CustomRealm();
+    }
+
+    @Bean
+    public ShiroFilterChainDefinition shiroFilterChainDefinition() {
+        DefaultShiroFilterChainDefinition filter = new DefaultShiroFilterChainDefinition();
+
+        filter.addPathDefinition("/home", "authc");
+        filter.addPathDefinition("/**", "anon");
+
+        return filter;
+    }
+
+}

apache-shiro/src/main/java/com/baeldung/comparison/shiro/controllers/ShiroController.java

@@ -0,0 +1,99 @@
+package com.baeldung.comparison.shiro.controllers;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.apache.shiro.SecurityUtils;
+import org.apache.shiro.authc.AuthenticationException;
+import org.apache.shiro.authc.UsernamePasswordToken;
+import org.apache.shiro.subject.Subject;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.servlet.mvc.support.RedirectAttributes;
+
+import com.baeldung.comparison.shiro.models.UserCredentials;
+
+@Controller
+public class ShiroController {
+    
+    private Logger logger = LoggerFactory.getLogger(ShiroController.class);
+
+    @GetMapping("/")
+    public String getIndex() {
+        return "comparison/index";
+    }
+
+    @GetMapping("/login")
+    public String showLoginPage() {
+        return "comparison/login";
+    }
+
+    @PostMapping("/login")
+    public String doLogin(HttpServletRequest req, UserCredentials credentials, RedirectAttributes attr) {
+
+        Subject subject = SecurityUtils.getSubject();
+
+        if (!subject.isAuthenticated()) {
+            UsernamePasswordToken token = new UsernamePasswordToken(credentials.getUsername(), credentials.getPassword());
+            try {
+                subject.login(token);
+            } catch (AuthenticationException ae) {
+                logger.error(ae.getMessage());
+                attr.addFlashAttribute("error", "Invalid Credentials");
+                return "redirect:/login";
+            }
+        }
+        return "redirect:/home";
+    }
+
+    @GetMapping("/home")
+    public String getMeHome(Model model) {
+
+        addUserAttributes(model);
+
+        return "comparison/home";
+    }
+
+    @GetMapping("/admin")
+    public String adminOnly(Model model) {
+        addUserAttributes(model);
+
+        Subject currentUser = SecurityUtils.getSubject();
+        if (currentUser.hasRole("ADMIN")) {
+            model.addAttribute("adminContent", "only admin can view this");
+        }
+        return "comparison/home";
+    }
+
+    @PostMapping("/logout")
+    public String logout() {
+        Subject subject = SecurityUtils.getSubject();
+        subject.logout();
+        return "redirect:/";
+    }
+
+    private void addUserAttributes(Model model) {
+        Subject currentUser = SecurityUtils.getSubject();
+        String permission = "";
+
+        if (currentUser.hasRole("ADMIN")) {
+            model.addAttribute("role", "ADMIN");
+        } else if (currentUser.hasRole("USER")) {
+            model.addAttribute("role", "USER");
+        }
+
+        if (currentUser.isPermitted("READ")) {
+            permission = permission + " READ";
+        }
+
+        if (currentUser.isPermitted("WRITE")) {
+            permission = permission + " WRITE";
+        }
+        model.addAttribute("username", currentUser.getPrincipal());
+        model.addAttribute("permission", permission);
+    }
+
+}

apache-shiro/src/main/java/com/baeldung/comparison/shiro/models/UserCredentials.java

@@ -0,0 +1,28 @@
+package com.baeldung.comparison.shiro.models;
+
+public class UserCredentials {
+
+    private String username;
+    private String password;
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    @Override
+    public String toString() {
+        return "username = " + getUsername();
+    }
+}

apache-shiro/src/main/java/com/baeldung/comparison/springsecurity/Application.java

@@ -0,0 +1,19 @@
+package com.baeldung.comparison.springsecurity;
+
+import org.apache.shiro.spring.boot.autoconfigure.ShiroAnnotationProcessorAutoConfiguration;
+import org.apache.shiro.spring.boot.autoconfigure.ShiroAutoConfiguration;
+import org.apache.shiro.spring.config.web.autoconfigure.ShiroWebAutoConfiguration;
+import org.apache.shiro.spring.config.web.autoconfigure.ShiroWebFilterConfiguration;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication(exclude = {ShiroAutoConfiguration.class,
+        ShiroAnnotationProcessorAutoConfiguration.class,
+        ShiroWebAutoConfiguration.class,
+        ShiroWebFilterConfiguration.class})
+public class Application {
+
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+}

apache-shiro/src/main/java/com/baeldung/comparison/springsecurity/config/SecurityConfig.java

@@ -0,0 +1,45 @@
+package com.baeldung.comparison.springsecurity.config;
+
+import org.springframework.context.annotation.Bean;
+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.crypto.bcrypt.BCryptPasswordEncoder;
+import org.springframework.security.crypto.password.PasswordEncoder;
+
+@EnableWebSecurity
+public class SecurityConfig extends WebSecurityConfigurerAdapter {
+
+    @Override
+    protected void configure(HttpSecurity http) throws Exception {
+        http.csrf().disable().authorizeRequests(authorize -> authorize.antMatchers("/index", "/login")
+            .permitAll()
+            .antMatchers("/home", "/logout")
+            .authenticated()
+            .antMatchers("/admin/**")
+            .hasRole("ADMIN"))
+            .formLogin(formLogin -> formLogin.loginPage("/login")
+                .failureUrl("/login-error"));
+    }
+
+    @Override
+    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
+        auth.inMemoryAuthentication()
+            .withUser("Jerry")
+            .password(passwordEncoder().encode("password"))
+            .authorities("READ", "WRITE")
+            .roles("ADMIN")
+            .and()
+            .withUser("Tom")
+            .password(passwordEncoder().encode("password"))
+            .authorities("READ")
+            .roles("USER");
+    }
+
+    @Bean
+    public PasswordEncoder passwordEncoder() {
+        return new BCryptPasswordEncoder();
+    }
+
+}

apache-shiro/src/main/java/com/baeldung/comparison/springsecurity/web/SpringController.java

@@ -0,0 +1,79 @@
+package com.baeldung.comparison.springsecurity.web;
+
+import java.util.Collection;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.springframework.security.authentication.AnonymousAuthenticationToken;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.GrantedAuthority;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.security.core.userdetails.User;
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+
+@Controller
+public class SpringController {
+
+    @GetMapping("/")
+    public String getIndex() {
+        return "comparison/index";
+    }
+
+    @GetMapping("/login")
+    public String showLoginPage() {
+        return "comparison/login";
+    }
+
+    @RequestMapping("/login-error")
+    public String loginError(Model model) {
+        model.addAttribute("error", "Invalid Credentials");
+        return "comparison/login";
+    }
+
+    @PostMapping("/login")
+    public String doLogin(HttpServletRequest req) {
+        return "redirect:/home";
+    }
+
+    @GetMapping("/home")
+    public String showHomePage(HttpServletRequest req, Model model) {
+        addUserAttributes(model);
+        return "comparison/home";
+    }
+
+    @GetMapping("/admin")
+    public String adminOnly(HttpServletRequest req, Model model) {
+        addUserAttributes(model);
+        model.addAttribute("adminContent", "only admin can view this");
+        return "comparison/home";
+    }
+
+    private void addUserAttributes(Model model) {
+        Authentication auth = SecurityContextHolder.getContext()
+            .getAuthentication();
+        if (auth != null && !auth.getClass()
+            .equals(AnonymousAuthenticationToken.class)) {
+            User user = (User) auth.getPrincipal();
+            model.addAttribute("username", user.getUsername());
+
+            Collection<GrantedAuthority> authorities = user.getAuthorities();
+
+            for (GrantedAuthority authority : authorities) {
+                if (authority.getAuthority()
+                    .contains("USER")) {
+                    model.addAttribute("role", "USER");
+                    model.addAttribute("permission", "READ");
+                } else if (authority.getAuthority()
+                    .contains("ADMIN")) {
+                    model.addAttribute("role", "ADMIN");
+                    model.addAttribute("permission", "READ WRITE");
+                }
+            }
+        }
+    }
+
+}

apache-shiro/src/main/java/com/baeldung/intro/Main.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.intro;
 
 import org.apache.shiro.SecurityUtils;
 import org.apache.shiro.authc.AuthenticationException;

apache-shiro/src/main/java/com/baeldung/intro/MyCustomRealm.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.intro;
 
 import java.sql.Connection;
 import java.sql.SQLException;

apache-shiro/src/main/java/com/baeldung/intro/ShiroSpringApplication.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.intro;
 
 import org.apache.shiro.realm.Realm;
 import org.apache.shiro.spring.web.config.DefaultShiroFilterChainDefinition;
@@ -7,12 +7,13 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration;
 import org.springframework.context.annotation.Bean;
 
 /**
  * Created by smatt on 21/08/2017.
  */
-@SpringBootApplication
+@SpringBootApplication(exclude = SecurityAutoConfiguration.class)
 public class ShiroSpringApplication {
 
     private static final transient Logger log = LoggerFactory.getLogger(ShiroSpringApplication.class);
@@ -29,7 +30,7 @@ public class ShiroSpringApplication {
 
 
     @Bean
-    public ShiroFilterChainDefinition shiroFilterChainDefinition() {
+    public ShiroFilterChainDefinition filterChainDefinition() {
         DefaultShiroFilterChainDefinition filter
           = new DefaultShiroFilterChainDefinition();