Merge branch 'eugenp:master' into master

apache-kafka/README.md

@@ -12,6 +12,7 @@ This module contains articles about Apache Kafka.
 - [Kafka Connect Example with MQTT and MongoDB](https://www.baeldung.com/kafka-connect-mqtt-mongodb)
 - [Building a Data Pipeline with Flink and Kafka](https://www.baeldung.com/kafka-flink-data-pipeline)
 - [Exactly Once Processing in Kafka with Java](https://www.baeldung.com/kafka-exactly-once)
+- [Custom Serializers in Apache Kafka](https://www.baeldung.com/kafka-custom-serializer)
 
 
 ##### Building the project

core-java-modules/core-java-12/README.md

@@ -2,3 +2,4 @@
 
 - [String API Updates in Java 12](https://www.baeldung.com/java12-string-api)
 - [New Features in Java 12](https://www.baeldung.com/java-12-new-features)
+- [Compare the Content of Two Files in Java](https://www.baeldung.com/java-compare-files)

core-java-modules/core-java-16/src/main/java/com/baeldung/java_16_features/mapmulti/Album.java

@@ -0,0 +1,49 @@
+package com.baeldung.java_16_features.mapmulti;
+
+import java.util.List;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+
+import org.apache.commons.lang3.tuple.ImmutablePair;
+import org.apache.commons.lang3.tuple.Pair;
+
+public class Album {
+
+    private String albumName;
+    private int albumCost;
+    private List<Artist> artists;
+
+    Album(String name, int albumCost, List<Artist> artists) {
+        this.albumName = name;
+        this.artists = artists;
+        this.albumCost = albumCost;
+    }
+
+    public void artistAlbumPairsToMajorLabels(Consumer<Pair<String, String>> consumer) {
+
+        for (Artist artist : artists) {
+            if (artist.isAssociatedMajorLabels()) {
+                String concatLabels = artist.getMajorLabels()
+                    .stream()
+                    .collect(Collectors.joining(","));
+                consumer.accept(new ImmutablePair<>(artist.getName() + ":" + albumName, concatLabels));
+            }
+        }
+    }
+
+    public String getAlbumName() {
+        return albumName;
+    }
+
+    public int getAlbumCost() {
+        return albumCost;
+    }
+
+    List<Artist> getArtists() {
+        return artists;
+    }
+
+    public String toString() {
+        return albumName;
+    }
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/java_16_features/mapmulti/Artist.java

@@ -0,0 +1,50 @@
+package com.baeldung.java_16_features.mapmulti;
+
+import java.util.List;
+import java.util.Objects;
+
+public class Artist {
+
+    private final String name;
+    private boolean associatedMajorLabels;
+    private List<String> majorLabels;
+
+    Artist(String name, boolean associatedMajorLabels, List<String> majorLabels) {
+        this.name = name;
+        this.associatedMajorLabels = associatedMajorLabels;
+        this.majorLabels = majorLabels;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public boolean isAssociatedMajorLabels() {
+        return associatedMajorLabels;
+    }
+
+    public List<String> getMajorLabels() {
+        return majorLabels;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        Artist other = (Artist) obj;
+        return Objects.equals(name, other.name);
+    }
+
+    public String toString() {
+        return name;
+    }
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/java_16_features/mapmulti/JavaStreamMapMultiUnitTest.java

@@ -0,0 +1,134 @@
+package com.baeldung.java_16_features.mapmulti;
+
+import static java.util.stream.Collectors.toList;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.offset;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.apache.commons.lang3.tuple.ImmutablePair;
+import org.apache.commons.lang3.tuple.Pair;
+import org.junit.jupiter.api.Test;
+
+public class JavaStreamMapMultiUnitTest {
+
+    private static final List<Album> albums = Arrays.asList(new Album("album1", 10, Arrays.asList(new Artist("bob", true, Arrays.asList("label1", "label3")), new Artist("tom", true, Arrays.asList("label2", "label3")))),
+        new Album("album2", 20, Arrays.asList(new Artist("bill", true, Arrays.asList("label2", "label3")), new Artist("tom", true, Arrays.asList("label2", "label4")))));
+
+    @Test
+    public void givenAListOfintegers_whenMapMulti_thenGetListOfOfEvenDoublesPlusPercentage() {
+
+        List<Integer> integers = Arrays.asList(1, 2, 3, 4, 5);
+        double percentage = .01;
+        List<Double> evenDoubles = integers.stream()
+            .<Double> mapMulti((integer, consumer) -> {
+                if (integer % 2 == 0) {
+                    consumer.accept((double) integer * (1 + percentage));
+                }
+            })
+            .collect(toList());
+
+        assertThat(evenDoubles).containsAll(Arrays.asList(2.02D, 4.04D));
+    }
+
+    @Test
+    public void givenAListOfintegers_whenFilterMap_thenGetListOfOfEvenDoublesPlusPercentage() {
+
+        List<Integer> integers = Arrays.asList(1, 2, 3, 4, 5);
+        double percentage = .01;
+        List<Double> evenDoubles = integers.stream()
+            .filter(integer -> integer % 2 == 0)
+            .<Double> map(integer -> ((double) integer * (1 + percentage)))
+            .collect(toList());
+
+        assertThat(evenDoubles).containsAll(Arrays.asList(2.02D, 4.04D));
+    }
+
+    @Test
+    public void givenAListOfintegers_whenMapMultiToDouble_thenGetSumOfEvenNumbersAfterApplyPercentage() {
+
+        List<Integer> integers = Arrays.asList(1, 2, 3, 4, 5, 6, 7);
+        double percentage = .01;
+        double sum = integers.stream()
+            .mapMultiToDouble((integer, consumer) -> {
+                if (integer % 2 == 0) {
+                    consumer.accept(integer * (1 + percentage));
+                }
+            })
+            .sum();
+
+        assertThat(sum).isEqualTo(12.12, offset(0.001d));
+    }
+
+    @Test
+    public void givenAListOfAlbums_whenFlatMap_thenGetListOfArtistAlbumPairs() {
+
+        List<Pair<String, String>> artistAlbum = albums.stream()
+            .flatMap(album -> album.getArtists()
+                .stream()
+                .map(artist -> new ImmutablePair<String, String>(artist.getName(), album.getAlbumName())))
+            .collect(toList());
+
+        assertThat(artistAlbum).contains(new ImmutablePair<String, String>("bob", "album1"), new ImmutablePair<String, 
+            String>("tom", "album1"), new ImmutablePair<String, String>("bill", "album2"), new ImmutablePair<String, String>("tom", "album2"));
+    }
+
+    @Test
+    public void givenAListOfAlbums_whenMapMulti_thenGetListOfPairsOfArtistAlbum() {
+
+        List<Pair<String, String>> artistAlbum = albums.stream()
+            .<Pair<String, String>> mapMulti((album, consumer) -> {
+                for (Artist artist : album.getArtists()) {
+                    consumer.accept(new ImmutablePair<String, String>(artist.getName(), album.getAlbumName()));
+                }
+            })
+            .collect(toList());
+
+        assertThat(artistAlbum).contains(new ImmutablePair<String, String>("bob", "album1"), new ImmutablePair<String, String>("tom", "album1"), 
+            new ImmutablePair<String, String>("bill", "album2"), new ImmutablePair<String, String>("tom", "album2"));
+    }
+
+    @Test
+    public void givenAListOfAlbums_whenFlatMap_thenGetListOfArtistAlbumjPairsBelowGivenCost() {
+
+        int upperCost = 9;
+        List<Pair<String, String>> artistAlbum = albums.stream()
+            .flatMap(album -> album.getArtists()
+                .stream()
+                .filter(artist -> upperCost > album.getAlbumCost())
+                .map(artist -> new ImmutablePair<String, String>(artist.getName(), album.getAlbumName())))
+            .collect(toList());
+
+        assertTrue(artistAlbum.isEmpty());
+    }
+
+    @Test
+    public void givenAListOfAlbums_whenMapMulti_thenGetListOfArtistAlbumPairsBelowGivenCost() {
+
+        int upperCost = 9;
+        List<Pair<String, String>> artistAlbum = albums.stream()
+            .<Pair<String, String>> mapMulti((album, consumer) -> {
+                if (album.getAlbumCost() < upperCost) {
+                    for (Artist artist : album.getArtists()) {
+                        consumer.accept(new ImmutablePair<String, String>(artist.getName(), album.getAlbumName()));
+                    }
+                }
+            })
+            .collect(toList());
+
+        assertTrue(artistAlbum.isEmpty());
+    }
+
+    @Test
+    public void givenAListOfAlbums_whenMapMulti_thenGetPairsOfArtistMajorLabelsUsingMethodReference() {
+
+        List<Pair<String, String>> artistLabels = albums.stream()
+            .mapMulti(Album::artistAlbumPairsToMajorLabels)
+            .collect(toList());
+
+        assertThat(artistLabels).contains(new ImmutablePair<String, String>("bob:album1", "label1,label3"), new ImmutablePair<String, String>("tom:album1", "label2,label3"), 
+            new ImmutablePair<String, String>("bill:album2", "label2,label3"), new ImmutablePair<String, String>("tom:album2", "label2,label4"));
+    }
+}

core-java-modules/core-java-datetime-string/README.md

@@ -11,3 +11,4 @@ This module contains articles about parsing and formatting Java date and time ob
 - [Display All Time Zones With GMT And UTC in Java](http://www.baeldung.com/java-time-zones)
 - [Convert between String and Timestamp](https://www.baeldung.com/java-string-to-timestamp)
 - [Convert String to Date in Java](http://www.baeldung.com/java-string-to-date)
+- [Format a Milliseconds Duration to HH:MM:SS](https://www.baeldung.com/java-ms-to-hhmmss)

core-java-modules/core-java-datetime-string/pom.xml

@@ -75,7 +75,7 @@
 
     <properties>
         <commons-validator.version>1.6</commons-validator.version>
-        <joda-time.version>2.10</joda-time.version>
+        <joda-time.version>2.10.10</joda-time.version>
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>
         <maven.compiler.source>1.9</maven.compiler.source>

core-java-modules/core-java-datetime-string/src/test/java/com/baeldung/formatduration/FormatDurationUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.formatduration;
+
+import org.apache.commons.lang3.time.DurationFormatUtils;
+import org.joda.time.Period;
+import org.junit.Test;
+
+import java.time.Duration;
+import java.util.concurrent.TimeUnit;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class FormatDurationUnitTest {
+
+
+    @Test
+    public void givenInterval_WhenFormatInterval_formatDuration() {
+        long HH = TimeUnit.MILLISECONDS.toHours(38114000);
+        long MM = TimeUnit.MILLISECONDS.toMinutes(38114000) % 60;
+        long SS = TimeUnit.MILLISECONDS.toSeconds(38114000) % 60;
+        String timeInHHMMSS = String.format("%02d:%02d:%02d", HH, MM, SS);
+
+        assertThat(timeInHHMMSS).isEqualTo("10:35:14");
+    }
+
+    @Test
+    public void givenInterval_WhenFormatUsingDuration_formatDuration() {
+        Duration duration = Duration.ofMillis(38114000);
+        long seconds = duration.getSeconds();
+        long HH = seconds / 3600;
+        long MM = (seconds % 3600) / 60;
+        long SS = seconds % 60;
+        String timeInHHMMSS =  String.format("%02d:%02d:%02d", HH, MM, SS);
+        assertThat(timeInHHMMSS).isEqualTo("10:35:14");
+    }
+
+
+    @Test
+    public void givenInterval_WhenFormatDurationUsingApacheCommons_formatDuration() {
+        assertThat(DurationFormatUtils.formatDuration(38114000, "HH:mm:ss"))
+          .isEqualTo("10:35:14");
+    }
+
+    @Test
+    public void givenInterval_WhenFormatDurationUsingJodaTime_formatDuration() {
+        org.joda.time.Duration duration = new org.joda.time.Duration(38114000);
+        Period period = duration.toPeriod();
+        long HH = period.getHours();
+        long MM = period.getMinutes();
+        long SS = period.getSeconds();
+
+        String timeInHHMMSS = String.format("%02d:%02d:%02d", HH, MM, SS);
+        assertThat(timeInHHMMSS).isEqualTo("10:35:14");
+    }
+}

javafx/README.md

@@ -4,4 +4,5 @@ This module contains articles about JavaFX.
 
 ### Relevant Articles:
 - [Introduction to JavaFX](https://www.baeldung.com/javafx)
+- [Display Custom Items in JavaFX ListView](https://www.baeldung.com/javafx-listview-display-custom-items)
 

jhipster/jhipster-microservice/car-app/pom.xml

@@ -17,7 +17,6 @@
     </prerequisites>
 
     <properties>
-        <lifecycle.mapping.version>1.0.0</lifecycle.mapping.version>
         <argLine>-Djava.security.egd=file:/dev/./urandom -Xmx256m</argLine>
         <assertj.version>3.6.2</assertj.version>
         <awaitility.version>2.0.0</awaitility.version>
@@ -31,6 +30,7 @@
         <jcache.version>1.0.0</jcache.version>
         <jhipster.server.version>1.1.0</jhipster.server.version>
         <jjwt.version>0.7.0</jjwt.version>
+        <lifecycle.mapping.version>1.0.0</lifecycle.mapping.version>
         <liquibase-hibernate5.version>3.6</liquibase-hibernate5.version>
         <liquibase-slf4j.version>2.0.0</liquibase-slf4j.version>
         <liquibase.version>3.6.2</liquibase.version>
@@ -349,7 +349,6 @@
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
-            <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
@@ -365,11 +364,6 @@
                 </exclusion>
             </exclusions>
         </dependency>
-        <dependency>
-            <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-test</artifactId>
-            <scope>test</scope>
-        </dependency>
         <!-- Spring Cloud -->
         <dependency>
             <groupId>org.springframework.cloud</groupId>
@@ -580,14 +574,6 @@
                     </execution>
                 </executions>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <configuration>
-                    <!-- Force alphabetical order to have a reproducible build -->
-                    <runOrder>alphabetical</runOrder>
-                </configuration>
-            </plugin>
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>

jhipster/jhipster-microservice/car-app/src/test/resources/config/application.yml

@@ -21,6 +21,8 @@ eureka:
         instanceId: carapp:${spring.application.instance_id:${random.value}}
 
 spring:
+    main:
+        banner-mode: "off"
     application:
         name: carapp
     jackson:
@@ -37,7 +39,7 @@ spring:
         database-platform: io.github.jhipster.domain.util.FixedH2Dialect
         database: H2
         open-in-view: false
-        show-sql: true
+        show-sql: false
         hibernate:
             ddl-auto: none
             naming:

jhipster/jhipster-microservice/car-app/src/test/resources/logback-test.xml

@@ -3,7 +3,7 @@
 <configuration scan="true">
     <include resource="org/springframework/boot/logging/logback/base.xml"/>
 
-    <logger name="com.car.app" level="DEBUG"/>
+    <logger name="com.car.app" level="INFO"/>
     <logger name="org.hibernate" level="WARN"/>
     <logger name="org.hibernate.ejb.HibernatePersistence" level="OFF"/>
     <logger name="org.apache.catalina.startup.DigesterFactory" level="OFF"/>

jhipster/jhipster-microservice/dealer-app/pom.xml

@@ -29,6 +29,7 @@
         <jcache.version>1.0.0</jcache.version>
         <jhipster.server.version>1.1.0</jhipster.server.version>
         <jjwt.version>0.7.0</jjwt.version>
+        <lifecycle.mapping.version>1.0.0</lifecycle.mapping.version>
         <liquibase-hibernate5.version>3.6</liquibase-hibernate5.version>
         <liquibase-slf4j.version>2.0.0</liquibase-slf4j.version>
         <liquibase.version>3.6.2</liquibase.version>
@@ -90,7 +91,6 @@
         <undertow.version>1.4.10.Final</undertow.version>
         <validation-api.version>1.1.0.Final</validation-api.version>
         <yarn.version>v0.21.3</yarn.version>
-        <lifecycle.mapping.version>1.0.0</lifecycle.mapping.version>
     </properties>
 
     <dependencyManagement>
@@ -345,6 +345,10 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-security</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-thymeleaf</artifactId>
@@ -359,11 +363,6 @@
                 </exclusion>
             </exclusions>
         </dependency>
-        <dependency>
-            <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-test</artifactId>
-            <scope>test</scope>
-        </dependency>
         <!-- Spring Cloud -->
         <dependency>
             <groupId>org.springframework.cloud</groupId>
@@ -574,14 +573,6 @@
                     </execution>
                 </executions>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <configuration>
-                    <!-- Force alphabetical order to have a reproducible build -->
-                    <runOrder>alphabetical</runOrder>
-                </configuration>
-            </plugin>
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>

jhipster/jhipster-microservice/dealer-app/src/test/resources/config/application.yml

@@ -21,6 +21,8 @@ eureka:
         instanceId: dealerapp:${spring.application.instance_id:${random.value}}
 
 spring:
+    main:
+        banner-mode: "off"
     application:
         name: dealerapp
     jackson:
@@ -37,7 +39,7 @@ spring:
         database-platform: io.github.jhipster.domain.util.FixedH2Dialect
         database: H2
         open-in-view: false
-        show-sql: true
+        show-sql: false
         hibernate:
             ddl-auto: none
             naming:

jhipster/jhipster-microservice/dealer-app/src/test/resources/logback-test.xml

@@ -3,7 +3,7 @@
 <configuration scan="true">
     <include resource="org/springframework/boot/logging/logback/base.xml"/>
 
-    <logger name="com.dealer.app" level="DEBUG"/>
+    <logger name="com.dealer.app" level="INFO"/>
     <logger name="org.hibernate" level="WARN"/>
     <logger name="org.hibernate.ejb.HibernatePersistence" level="OFF"/>
     <logger name="org.apache.catalina.startup.DigesterFactory" level="OFF"/>

jhipster/jhipster-microservice/gateway-app/pom.xml

@@ -32,6 +32,7 @@
         <jcache.version>1.0.0</jcache.version>
         <jhipster.server.version>1.1.0</jhipster.server.version>
         <jjwt.version>0.7.0</jjwt.version>
+        <lifecycle.mapping.version>1.0.0</lifecycle.mapping.version>
         <liquibase-hibernate5.version>3.6</liquibase-hibernate5.version>
         <liquibase-slf4j.version>2.0.0</liquibase-slf4j.version>
         <liquibase.version>3.6.2</liquibase.version>
@@ -94,7 +95,6 @@
         <undertow.version>1.4.10.Final</undertow.version>
         <validation-api.version>1.1.0.Final</validation-api.version>
         <yarn.version>v0.21.3</yarn.version>
-        <lifecycle.mapping.version>1.0.0</lifecycle.mapping.version>
     </properties>
 
     <dependencyManagement>
@@ -383,6 +383,10 @@
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-thymeleaf</artifactId>
@@ -397,11 +401,6 @@
                 </exclusion>
             </exclusions>
         </dependency>
-        <dependency>
-            <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-test</artifactId>
-            <scope>test</scope>
-        </dependency>
         <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter</artifactId>
@@ -632,14 +631,6 @@
                     </execution>
                 </executions>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <configuration>
-                    <!-- Force alphabetical order to have a reproducible build -->
-                    <runOrder>alphabetical</runOrder>
-                </configuration>
-            </plugin>
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>

jhipster/jhipster-microservice/gateway-app/src/test/java/com/gateway/web/rest/LogsResourceIntegrationTest.java

@@ -49,7 +49,7 @@ public class LogsResourceIntegrationTest {
     public void changeLogs()throws Exception {
         LoggerVM logger = new LoggerVM();
         logger.setLevel("INFO");
-        logger.setName("ROOT");
+        logger.setName("some.test.logger");
 
         restLogsMockMvc.perform(put("/management/logs")
             .contentType(TestUtil.APPLICATION_JSON_UTF8)

jhipster/jhipster-microservice/gateway-app/src/test/resources/config/application.yml

@@ -21,6 +21,8 @@ eureka:
         instanceId: gateway:${spring.application.instance_id:${random.value}}
 
 spring:
+    main:
+        banner-mode: "off"
     application:
         name: gateway
     autoconfigure:
@@ -39,7 +41,7 @@ spring:
         database-platform: io.github.jhipster.domain.util.FixedH2Dialect
         database: H2
         open-in-view: false
-        show-sql: true
+        show-sql: false
         hibernate:
             ddl-auto: none
             naming:

jhipster/jhipster-microservice/gateway-app/src/test/resources/logback-test.xml

@@ -3,7 +3,7 @@
 <configuration scan="true">
     <include resource="org/springframework/boot/logging/logback/base.xml"/>
 
-    <logger name="com.gateway" level="DEBUG"/>
+    <logger name="com.gateway" level="INFO"/>
     <logger name="org.hibernate" level="WARN"/>
     <logger name="org.hibernate.ejb.HibernatePersistence" level="OFF"/>
     <logger name="org.apache.catalina.startup.DigesterFactory" level="OFF"/>

jhipster/jhipster-monolithic/pom.xml

@@ -277,8 +277,7 @@
         </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-test</artifactId>
+            <artifactId>spring-boot-starter-test</artifactId>
-            <scope>test</scope>
         </dependency>
         <!-- security -->
         <dependency>

jhipster/jhipster-monolithic/src/test/java/com/baeldung/web/rest/LogsResourceIntegrationTest.java

@@ -49,7 +49,7 @@ public class LogsResourceIntegrationTest {
     public void changeLogs()throws Exception {
         LoggerVM logger = new LoggerVM();
         logger.setLevel("INFO");
-        logger.setName("ROOT");
+        logger.setName("some.test.logger");
 
         restLogsMockMvc.perform(put("/management/logs")
             .contentType(TestUtil.APPLICATION_JSON_UTF8)

jhipster/jhipster-monolithic/src/test/resources/config/application.yml

@@ -15,6 +15,8 @@
 
 
 spring:
+    main:
+        banner-mode: "off"
     application:
         name: baeldung
     jackson:
@@ -31,7 +33,7 @@ spring:
         database-platform: io.github.jhipster.domain.util.FixedH2Dialect
         database: H2
         open-in-view: false
-        show-sql: true
+        show-sql: false
         hibernate:
             ddl-auto: none
             naming:

jhipster/jhipster-monolithic/src/test/resources/logback-test.xml

@@ -3,7 +3,7 @@
 <configuration scan="true">
     <include resource="org/springframework/boot/logging/logback/base.xml"/>
 
-    <logger name="com.baeldung" level="DEBUG"/>
+    <logger name="com.baeldung" level="INFO"/>
     <logger name="org.hibernate" level="WARN"/>
     <logger name="org.hibernate.ejb.HibernatePersistence" level="OFF"/>
     <logger name="org.apache.catalina.startup.DigesterFactory" level="OFF"/>

jhipster/jhipster-uaa/gateway/pom.xml

@@ -1,6 +1,13 @@
 <?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/maven-v4_0_0.xsd">
     <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <artifactId>jhipster-uaa</artifactId>
+        <groupId>com.baeldung.jhipster</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
     <groupId>com.baeldung.jhipster.gateway</groupId>
     <artifactId>gateway</artifactId>
     <version>0.0.1-SNAPSHOT</version>
@@ -415,15 +422,6 @@
                     </execution>
                 </executions>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <version>${maven-surefire-plugin.version}</version>
-                <configuration>
-                    <!-- Force alphabetical order to have a reproducible build -->
-                    <runOrder>alphabetical</runOrder>
-                </configuration>
-            </plugin>
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>

jhipster/jhipster-uaa/gateway/src/test/java/com/baeldung/jhipster/gateway/config/WebConfigurerUnitTest.java

@@ -40,7 +40,7 @@ import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.
  *
  * @see WebConfigurer
  */
-public class WebConfigurerTest {
+public class WebConfigurerUnitTest {
 
     private WebConfigurer webConfigurer;
 

jhipster/jhipster-uaa/gateway/src/test/java/com/baeldung/jhipster/gateway/gateway/responserewriting/SwaggerBasePathRewritingFilterUnitTest.java

@@ -18,7 +18,7 @@ import static springfox.documentation.swagger2.web.Swagger2Controller.DEFAULT_UR
 /**
  * Tests SwaggerBasePathRewritingFilter class.
  */
-public class SwaggerBasePathRewritingFilterTest {
+public class SwaggerBasePathRewritingFilterUnitTest {
 
     private SwaggerBasePathRewritingFilter filter = new SwaggerBasePathRewritingFilter();
 

jhipster/jhipster-uaa/gateway/src/test/java/com/baeldung/jhipster/gateway/security/oauth2/CookieCollectionUnitTest.java

@@ -16,7 +16,7 @@ import java.util.List;
  *
  * @see CookieCollection
  */
-public class CookieCollectionTest {
+public class CookieCollectionUnitTest {
     public static final String COOKIE_NAME = "chocolate";
     public static final String COOKIE_VALUE = "yummy";
     public static final String BROWNIE_NAME = "brownie";

jhipster/jhipster-uaa/gateway/src/test/java/com/baeldung/jhipster/gateway/security/oauth2/CookieTokenExtractorUnitTest.java

@@ -12,7 +12,7 @@ import org.springframework.security.oauth2.common.OAuth2AccessToken;
  * Test whether the CookieTokenExtractor can properly extract access tokens from
  * Cookies and Headers.
  */
-public class CookieTokenExtractorTest {
+public class CookieTokenExtractorUnitTest {
     private CookieTokenExtractor cookieTokenExtractor;
 
     @Before
@@ -22,24 +22,24 @@ public class CookieTokenExtractorTest {
 
     @Test
     public void testExtractTokenCookie() {
-        MockHttpServletRequest request = OAuth2AuthenticationServiceTest.createMockHttpServletRequest();
+        MockHttpServletRequest request = OAuth2AuthenticationServiceUnitTest.createMockHttpServletRequest();
         Authentication authentication = cookieTokenExtractor.extract(request);
-        Assert.assertEquals(OAuth2AuthenticationServiceTest.ACCESS_TOKEN_VALUE, authentication.getPrincipal().toString());
+        Assert.assertEquals(OAuth2AuthenticationServiceUnitTest.ACCESS_TOKEN_VALUE, authentication.getPrincipal().toString());
     }
 
     @Test
     public void testExtractTokenHeader() {
         MockHttpServletRequest request = new MockHttpServletRequest(HttpMethod.GET.name(), "http://www.test.com");
-        request.addHeader("Authorization", OAuth2AccessToken.BEARER_TYPE + " " + OAuth2AuthenticationServiceTest.ACCESS_TOKEN_VALUE);
+        request.addHeader("Authorization", OAuth2AccessToken.BEARER_TYPE + " " + OAuth2AuthenticationServiceUnitTest.ACCESS_TOKEN_VALUE);
         Authentication authentication = cookieTokenExtractor.extract(request);
-        Assert.assertEquals(OAuth2AuthenticationServiceTest.ACCESS_TOKEN_VALUE, authentication.getPrincipal().toString());
+        Assert.assertEquals(OAuth2AuthenticationServiceUnitTest.ACCESS_TOKEN_VALUE, authentication.getPrincipal().toString());
     }
 
     @Test
     public void testExtractTokenParam() {
         MockHttpServletRequest request = new MockHttpServletRequest(HttpMethod.GET.name(), "http://www.test.com");
-        request.addParameter(OAuth2AccessToken.ACCESS_TOKEN, OAuth2AuthenticationServiceTest.ACCESS_TOKEN_VALUE);
+        request.addParameter(OAuth2AccessToken.ACCESS_TOKEN, OAuth2AuthenticationServiceUnitTest.ACCESS_TOKEN_VALUE);
         Authentication authentication = cookieTokenExtractor.extract(request);
-        Assert.assertEquals(OAuth2AuthenticationServiceTest.ACCESS_TOKEN_VALUE, authentication.getPrincipal().toString());
+        Assert.assertEquals(OAuth2AuthenticationServiceUnitTest.ACCESS_TOKEN_VALUE, authentication.getPrincipal().toString());
     }
 }

jhipster/jhipster-uaa/gateway/src/test/java/com/baeldung/jhipster/gateway/security/oauth2/OAuth2AuthenticationServiceUnitTest.java

@@ -39,7 +39,7 @@ import static org.mockito.Mockito.when;
  * @see OAuth2AuthenticationService
  */
 @RunWith(MockitoJUnitRunner.class)
-public class OAuth2AuthenticationServiceTest {
+public class OAuth2AuthenticationServiceUnitTest {
     public static final String CLIENT_AUTHORIZATION = "Basic d2ViX2FwcDpjaGFuZ2VpdA==";
     public static final String ACCESS_TOKEN_VALUE = "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE0OTQyNzI4NDQsInVzZXJfbmFtZSI6InVzZXIiLCJhdXRob3JpdGllcyI6WyJST0xFX1VTRVIiXSwianRpIjoiNzc1ZTJkYWUtYWYzZi00YTdhLWExOTktNzNiZTU1MmIxZDVkIiwiY2xpZW50X2lkIjoid2ViX2FwcCIsInNjb3BlIjpbIm9wZW5pZCJdfQ.gEK0YcX2IpkpxnkxXXHQ4I0xzTjcy7edqb89ukYE0LPe7xUcZVwkkCJF_nBxsGJh2jtA6NzNLfY5zuL6nP7uoAq3fmvsyrcyR2qPk8JuuNzGtSkICx3kPDRjAT4ST8SZdeh7XCbPVbySJ7ZmPlRWHyedzLA1wXN0NUf8yZYS4ELdUwVBYIXSjkNoKqfWm88cwuNr0g0teypjPtjDqCnXFt1pibwdfIXn479Y1neNAdvSpHcI4Ost-c7APCNxW2gqX-0BItZQearxRgKDdBQ7CGPAIky7dA0gPuKUpp_VCoqowKCXqkE9yKtRQGIISewtj2UkDRZePmzmYrUBXRzfYw";
     public static final String REFRESH_TOKEN_VALUE = "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyX25hbWUiOiJ1c2VyIiwic2NvcGUiOlsib3BlbmlkIl0sImF0aSI6Ijc3NWUyZGFlLWFmM2YtNGE3YS1hMTk5LTczYmU1NTJiMWQ1ZCIsImV4cCI6MTQ5Njg2NDc0MywiYXV0aG9yaXRpZXMiOlsiUk9MRV9VU0VSIl0sImp0aSI6IjhmYjI2YTllLTdjYzQtNDFlMi1hNzBjLTk4MDc0N2U2YWFiOSIsImNsaWVudF9pZCI6IndlYl9hcHAifQ.q1-Df9_AFO6TJNiLKV2YwTjRbnd7qcXv52skXYnog5siHYRoR6cPtm6TNQ04iDAoIHljTSTNnD6DS3bHk41mV55gsSVxGReL8VCb_R8ZmhVL4-5yr90sfms0wFp6lgD2bPmZ-TXiS2Oe9wcbNWagy5RsEplZ-sbXu3tjmDao4FN35ojPsXmUs84XnNQH3Y_-PY9GjZG0JEfLQIvE0J5BkXS18Z015GKyA6GBIoLhAGBQQYyG9m10ld_a9fD5SmCyCF72Jad_pfP1u8Z_WyvO-wrlBvm2x-zBthreVrXU5mOb9795wJEP-xaw3dXYGjht_grcW4vKUFtj61JgZk98CQ";

jhipster/jhipster-uaa/gateway/src/test/java/com/baeldung/jhipster/gateway/security/oauth2/OAuth2CookieHelperUnitTest.java

@@ -12,7 +12,7 @@ import org.springframework.test.util.ReflectionTestUtils;
  *
  * @see OAuth2CookieHelper
  */
-public class OAuth2CookieHelperTest {
+public class OAuth2CookieHelperUnitTest {
     public static final String GET_COOKIE_DOMAIN_METHOD = "getCookieDomain";
     private OAuth2Properties oAuth2Properties;
     private OAuth2CookieHelper cookieHelper;

jhipster/jhipster-uaa/gateway/src/test/java/com/baeldung/jhipster/gateway/web/rest/LogsResourceIntTest.java

@@ -51,7 +51,7 @@ public class LogsResourceIntTest {
     public void changeLogs() throws Exception {
         LoggerVM logger = new LoggerVM();
         logger.setLevel("INFO");
-        logger.setName("ROOT");
+        logger.setName("some.test.logger");
 
         restLogsMockMvc.perform(put("/management/logs")
             .contentType(TestUtil.APPLICATION_JSON_UTF8)

jhipster/jhipster-uaa/gateway/src/test/resources/config/application.yml

@@ -21,6 +21,8 @@ eureka:
         instanceId: gateway:${spring.application.instance-id:${random.value}}
 
 spring:
+    main:
+        banner-mode: "off"
     application:
         name: gateway
     cache:

jhipster/jhipster-uaa/quotes/pom.xml

@@ -1,6 +1,13 @@
 <?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/maven-v4_0_0.xsd">
     <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <artifactId>jhipster-uaa</artifactId>
+        <groupId>com.baeldung.jhipster</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
     <groupId>com.baeldung.jhipster.quotes</groupId>
     <artifactId>quotes</artifactId>
     <version>0.0.1-SNAPSHOT</version>
@@ -399,15 +406,6 @@
                     </execution>
                 </executions>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <version>${maven-surefire-plugin.version}</version>
-                <configuration>
-                    <!-- Force alphabetical order to have a reproducible build -->
-                    <runOrder>alphabetical</runOrder>
-                </configuration>
-            </plugin>
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>

jhipster/jhipster-uaa/quotes/src/test/java/com/baeldung/jhipster/quotes/config/WebConfigurerUnitTest.java

@@ -38,7 +38,7 @@ import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.
  *
  * @see WebConfigurer
  */
-public class WebConfigurerTest {
+public class WebConfigurerUnitTest {
 
     private WebConfigurer webConfigurer;
 

jhipster/jhipster-uaa/quotes/src/test/java/com/baeldung/jhipster/quotes/web/rest/LogsResourceIntTest.java

@@ -51,7 +51,7 @@ public class LogsResourceIntTest {
     public void changeLogs() throws Exception {
         LoggerVM logger = new LoggerVM();
         logger.setLevel("INFO");
-        logger.setName("ROOT");
+        logger.setName("some.test.logger");
 
         restLogsMockMvc.perform(put("/management/logs")
             .contentType(TestUtil.APPLICATION_JSON_UTF8)

jhipster/jhipster-uaa/quotes/src/test/resources/config/application.yml

@@ -21,6 +21,8 @@ eureka:
         instanceId: quotes:${spring.application.instance-id:${random.value}}
 
 spring:
+    main:
+        banner-mode: "off"
     application:
         name: quotes
     cache:

jhipster/jhipster-uaa/uaa/pom.xml

@@ -1,6 +1,12 @@
 <?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/maven-v4_0_0.xsd">
     <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <artifactId>jhipster-uaa</artifactId>
+        <groupId>com.baeldung.jhipster</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
     <groupId>com.baeldung.jhipster.uaa</groupId>
     <artifactId>uaa</artifactId>
     <version>0.0.1-SNAPSHOT</version>
@@ -399,15 +405,6 @@
                     </execution>
                 </executions>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <version>${maven-surefire-plugin.version}</version>
-                <configuration>
-                    <!-- Force alphabetical order to have a reproducible build -->
-                    <runOrder>alphabetical</runOrder>
-                </configuration>
-            </plugin>
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>

jhipster/jhipster-uaa/uaa/src/test/java/com/baeldung/jhipster/uaa/config/WebConfigurerUnitTest.java

@@ -38,7 +38,7 @@ import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.
  *
  * @see WebConfigurer
  */
-public class WebConfigurerTest {
+public class WebConfigurerUnitTest {
 
     private WebConfigurer webConfigurer;
 

jhipster/jhipster-uaa/uaa/src/test/java/com/baeldung/jhipster/uaa/web/rest/LogsResourceIntTest.java

@@ -51,7 +51,7 @@ public class LogsResourceIntTest {
     public void changeLogs() throws Exception {
         LoggerVM logger = new LoggerVM();
         logger.setLevel("INFO");
-        logger.setName("ROOT");
+        logger.setName("some.test.logger");
 
         restLogsMockMvc.perform(put("/management/logs")
             .contentType(TestUtil.APPLICATION_JSON_UTF8)

jhipster/jhipster-uaa/uaa/src/test/resources/config/application.yml

@@ -21,6 +21,8 @@ eureka:
         instanceId: uaa:${spring.application.instance-id:${random.value}}
 
 spring:
+    main:
+        banner-mode: "off"
     application:
         name: uaa
     cache:

jhipster/pom.xml

@@ -17,11 +17,39 @@
         <relativePath>../parent-boot-1</relativePath>
     </parent>
 
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-starter-test</artifactId>
+                <version>${spring-boot.version}</version>
+                <exclusions>
+                    <exclusion>
+                        <groupId>com.vaadin.external.google</groupId>
+                        <artifactId>android-json</artifactId>
+                    </exclusion>
+                    <exclusion>
+                        <groupId>org.json</groupId>
+                        <artifactId>json</artifactId>
+                    </exclusion>
+                </exclusions>
+                <scope>test</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
     <dependencies>
         <dependency>
             <groupId>org.hibernate</groupId>
             <artifactId>hibernate-java8</artifactId>
         </dependency>
+
+        <dependency>
+            <groupId>net.bytebuddy</groupId>
+            <artifactId>byte-buddy</artifactId>
+            <version>${byte-buddy.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <modules>

ksqldb/README.md

@@ -0,0 +1,3 @@
+### Relevant Articles:
+
+- [Introduction to ksqlDB](https://www.baeldung.com/ksqldb)

libraries-security/pom.xml

@@ -78,6 +78,29 @@
             <artifactId>sshd-core</artifactId>
             <version>${apache-mina.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.xacml4j</groupId>
+            <artifactId>xacml-core</artifactId>
+            <version>${xacml4j.version}</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.slf4j</groupId>
+                    <artifactId>slf4j-log4j12</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>org.xacml4j</groupId>
+            <artifactId>xacml-test</artifactId>
+            <version>${xacml4j.version}</version>
+            <scope>test</scope>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.slf4j</groupId>
+                    <artifactId>slf4j-log4j12</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
     </dependencies>
 
     <properties>
@@ -90,6 +113,7 @@
         <jsch.version>0.1.55</jsch.version>
         <apache-mina.version>2.5.1</apache-mina.version>
         <spring-security-oauth2.version>2.4.0.RELEASE</spring-security-oauth2.version>
+        <xacml4j.version>1.4.0</xacml4j.version>
     </properties>
 
 </project>

libraries-security/src/main/java/com/baeldung/scribejava/ScribejavaApplication.java

@@ -2,9 +2,11 @@ package com.baeldung.scribejava;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.web.servlet.ServletComponentScan;
 
 
 @SpringBootApplication
+@ServletComponentScan
 public class ScribejavaApplication {
 
     public static void main(String[] args) {

libraries-security/src/main/java/com/baeldung/scribejava/controller/RBACController.java

@@ -0,0 +1,27 @@
+package com.baeldung.scribejava.controller;
+
+import java.io.IOException;
+
+import javax.annotation.security.DeclareRoles;
+import javax.annotation.security.RolesAllowed;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.HttpConstraint;
+import javax.servlet.annotation.ServletSecurity;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+@WebServlet(name="rbac", urlPatterns = {"/protected"})
+@DeclareRoles("USER")
+@ServletSecurity(
+    @HttpConstraint(rolesAllowed = "USER")
+)
+public class RBACController  extends HttpServlet {
+
+    private static final long serialVersionUID = 1L;
+
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        resp.getWriter().println("Hello, USER");
+    }
+}

libraries-security/src/test/java/com/baeldung/xacml4j/NightlyWithdrawalPolicyUnitTest.java

@@ -0,0 +1,233 @@
+package com.baeldung.xacml4j;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.Test;
+import org.xacml4j.v20.Xacml20TestUtility;
+import org.xacml4j.v30.Attribute;
+import org.xacml4j.v30.Categories;
+import org.xacml4j.v30.Category;
+import org.xacml4j.v30.CompositeDecisionRule;
+import org.xacml4j.v30.Decision;
+import org.xacml4j.v30.Entity;
+import org.xacml4j.v30.RequestContext;
+import org.xacml4j.v30.ResponseContext;
+import org.xacml4j.v30.Result;
+import org.xacml4j.v30.XacmlPolicyTestSupport;
+import org.xacml4j.v30.pdp.PolicyDecisionPoint;
+import org.xacml4j.v30.pdp.PolicyDecisionPointBuilder;
+import org.xacml4j.v30.spi.combine.DecisionCombiningAlgorithmProviderBuilder;
+import org.xacml4j.v30.spi.function.FunctionProviderBuilder;
+import org.xacml4j.v30.spi.pip.PolicyInformationPointBuilder;
+import org.xacml4j.v30.spi.repository.InMemoryPolicyRepository;
+import org.xacml4j.v30.spi.repository.PolicyRepository;
+import org.xacml4j.v30.types.DoubleExp;
+import org.xacml4j.v30.types.StringExp;
+import org.xacml4j.v30.types.TimeExp;
+
+public class NightlyWithdrawalPolicyUnitTest extends XacmlPolicyTestSupport {
+    
+    private static final String POLICY_SET = "xacml4j/NightlyWithdrawalsPolicy.xml";
+
+    @Test
+    public void testWhenNightlyWithdrawalOver500_thenFail() throws Exception {
+
+        PolicyDecisionPoint pdp = buildPDP(POLICY_SET);
+
+        // Action category
+        Attribute actionAttribute = Attribute.builder("urn:oasis:names:tc:xacml:1.0:action:action-id")
+            .value(StringExp.of("withdrawal"))
+            .build();
+        Entity actionEntity = Entity.builder()
+            .attribute(actionAttribute)
+            .build();
+        Category actionCategory = Category.builder(Categories.ACTION)
+            .entity(actionEntity)
+            .build();
+
+        // Environment Category
+        Attribute timeAttribute = Attribute.builder("urn:oasis:names:tc:xacml:1.0:environment:current-time")
+            .includeInResult(false)
+            .value(TimeExp.of("21:00:00"))
+            .build();
+        Entity timeEntity = Entity.builder()
+            .attribute(timeAttribute)
+            .build();
+
+        Category environmentCategory = Category.builder(Categories.ENVIRONMENT)
+            .entity(timeEntity)
+            .build();
+
+        // ATM category
+        Attribute amountAttribute = Attribute.builder("urn:baeldung:atm:withdrawal:amount")
+            .value(DoubleExp.of("1200.00"))
+            .build();
+        Entity atmEntity = Entity.builder()
+            .attribute(amountAttribute)
+            .build();
+
+        Category atmCategory = Category.builder(Categories.parse("urn:baeldung:atm:withdrawal"))
+            .entity(atmEntity)
+            .build();
+
+        RequestContext request = RequestContext.builder()
+            .attributes(actionCategory, environmentCategory, atmCategory)
+            .build();
+
+        ResponseContext response = pdp.decide(request);
+        assertNotNull(response);
+        assertTrue("Shoud have at least one result", response.getResults() != null && !response.getResults()
+            .isEmpty());
+
+        Result result = response.getResults()
+            .iterator()
+            .next();
+        assertTrue("Evaluation should succeed", result.getStatus()
+            .isSuccess());
+        assertEquals("Should DENY withdrawal", Decision.DENY, result.getDecision());
+
+    }
+
+    @Test
+    public void testWhenNightlyWithdrawalUnder500_thenSuccess() throws Exception {
+
+        PolicyDecisionPoint pdp = buildPDP(POLICY_SET);
+
+        // Action category
+        Attribute actionAttribute = Attribute.builder("urn:oasis:names:tc:xacml:1.0:action:action-id")
+            .includeInResult(false)
+            .value(StringExp.of("withdrawal"))
+            .build();
+        Entity actionEntity = Entity.builder()
+            .attribute(actionAttribute)
+            .build();
+        Category actionCategory = Category.builder(Categories.ACTION)
+            .entity(actionEntity)
+            .build();
+
+        // Environment Category
+        Attribute timeAttribute = Attribute.builder("urn:oasis:names:tc:xacml:1.0:environment:current-time")
+            .includeInResult(false)
+            .value(TimeExp.of("21:00:00"))
+            .build();
+        Entity timeEntity = Entity.builder()
+            .attribute(timeAttribute)
+            .build();
+        Category environmentCategory = Category.builder(Categories.ENVIRONMENT)
+            .entity(timeEntity)
+            .build();
+
+        // ATM category
+        Attribute amountAttribute = Attribute.builder("urn:baeldung:atm:withdrawal:amount")
+            .value(DoubleExp.of("499.00"))
+            .build();
+        Entity atmEntity = Entity.builder()
+          .attribute(amountAttribute)
+          .build();
+        Category atmCategory = Category.builder(Categories.parse("urn:baeldung:atm:withdrawal"))
+          .entity(atmEntity)
+          .build();
+
+        RequestContext request = RequestContext.builder()
+          .attributes(actionCategory, environmentCategory, atmCategory)
+          .build();
+
+        ResponseContext response = pdp.decide(request);
+        assertNotNull(response);
+        assertTrue("Shoud have at least one result", 
+          response.getResults() != null && !response.getResults().isEmpty());
+
+        Result result = response.getResults().iterator().next();
+        assertTrue("Evaluation should succeed", result.getStatus().isSuccess());
+        assertEquals("Should PERMIT withdrawal", Decision.PERMIT, result.getDecision());
+
+    }
+
+    @Test
+    public void testWhenBusinessHoursWithdrawalOver500_thenSuccess() throws Exception {
+
+        PolicyDecisionPoint pdp = buildPDP(POLICY_SET);
+
+        // Action category
+        Attribute actionAttribute = Attribute.builder("urn:oasis:names:tc:xacml:1.0:action:action-id")
+          .includeInResult(false)
+          .value(StringExp.of("withdrawal"))
+          .build();
+        Entity actionEntity = Entity.builder()
+          .attribute(actionAttribute)
+          .build();
+        Category actionCategory = Category.builder(Categories.ACTION)
+          .entity(actionEntity)
+          .build();
+
+        // Environment Category
+        Attribute timeAttribute = Attribute.builder("urn:oasis:names:tc:xacml:1.0:environment:current-time")
+          .includeInResult(false)
+          .value(TimeExp.of("12:00:00"))
+          .build();
+        Entity timeEntity = Entity.builder()
+          .attribute(timeAttribute)
+          .build();
+        Category environmentCategory = Category.builder(Categories.ENVIRONMENT)
+          .entity(timeEntity)
+          .build();
+
+        // ATM category
+        Attribute amountAttribute = Attribute.builder("urn:baeldung:atm:withdrawal:amount")
+          .value(DoubleExp.of("2000.00"))
+          .build();
+        Entity atmEntity = Entity.builder()
+          .attribute(amountAttribute)
+          .build();
+
+        Category atmCategory = Category.builder(Categories.parse("urn:baeldung:atm:withdrawal"))
+          .entity(atmEntity)
+          .build();
+
+        RequestContext request = RequestContext.builder()
+          .attributes(actionCategory, environmentCategory, atmCategory)
+          .build();
+
+        ResponseContext response = pdp.decide(request);
+        assertNotNull(response);
+        assertTrue("Shoud have at least one result", response.getResults() != null && !response.getResults()
+          .isEmpty());
+
+        Result result = response.getResults()
+          .iterator()
+          .next();
+        assertTrue("Evaluation should succeed", result.getStatus().isSuccess());
+        assertEquals("Should PERMIT withdrawal", Decision.PERMIT, result.getDecision());
+
+    }
+
+    private PolicyDecisionPoint buildPDP(String... policyResources) throws Exception {
+        PolicyRepository repository = new InMemoryPolicyRepository("tes-repository", FunctionProviderBuilder.builder()
+          .defaultFunctions()
+          .build(),
+        DecisionCombiningAlgorithmProviderBuilder.builder()
+            .withDefaultAlgorithms()
+            .create());
+
+        List<CompositeDecisionRule> policies = new ArrayList<CompositeDecisionRule>(policyResources.length);
+        for (String policyResource : policyResources) {
+            CompositeDecisionRule policy = repository.importPolicy(Xacml20TestUtility.getClasspathResource(policyResource));
+            log.info("Policy: {}", policy);
+            policies.add(policy);
+        }
+
+        return PolicyDecisionPointBuilder.builder("testPdp")
+          .policyRepository(repository)
+          .pip(PolicyInformationPointBuilder.builder("testPip")
+          .defaultResolvers()
+          .build())
+          .rootPolicy(policies.get(0))
+          .build();
+    }
+
+}

libraries-security/src/test/resources/xacml4j/NightlyWithdrawalsPolicy.xml

@@ -0,0 +1,137 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Policy xmlns="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17" 
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+  xsi:schemaLocation="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17 http://docs.oasis-open.org/xacml/3.0/xacml-core-v3-schema-wd-17.xsd" 
+  PolicyId="urn:baeldung:atm:WithdrawalPolicy"
+  Version="1.0" 
+  RuleCombiningAlgId="urn:oasis:names:tc:xacml:1.0:rule-combining-algorithm:deny-overrides">
+    <Description>
+       Withdrawal policy example
+    </Description>
+    <Target/>
+    <Rule RuleId="urn:oasis:names:tc:baeldung:WithDrawalPolicy:Rule1" Effect="Deny">
+        <Description>
+Deny withdrawals over $500 between 20:00 and 08:00
+        </Description>
+        <Target>
+            <AnyOf>
+                <AllOf>
+                    <Match MatchId="urn:oasis:names:tc:xacml:1.0:function:string-equal">
+                        <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">withdrawal</AttributeValue>
+                        <AttributeDesignator 
+                            DataType="http://www.w3.org/2001/XMLSchema#string" 
+                            MustBePresent="true" 
+                            Category="urn:oasis:names:tc:xacml:3.0:attribute-category:action" 
+                            AttributeId="urn:oasis:names:tc:xacml:1.0:action:action-id"/>
+                    </Match>
+                </AllOf>
+            </AnyOf>
+        </Target>
+        <Condition>
+            <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:and">
+                <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:not">
+                    <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:time-in-range">
+                        <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:time-one-and-only">
+                            <AttributeDesignator
+                                DataType="http://www.w3.org/2001/XMLSchema#time"
+                                MustBePresent="true"
+                                Category="urn:oasis:names:tc:xacml:3.0:attribute-category:environment"
+                                AttributeId="urn:oasis:names:tc:xacml:1.0:environment:current-time"/>
+                        </Apply>
+                        <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#time">08:00:00</AttributeValue>
+                        <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#time">20:00:00</AttributeValue>
+                    </Apply>
+                </Apply>
+                <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:double-greater-than">
+                    <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:double-one-and-only">
+                        <AttributeDesignator
+                            DataType="http://www.w3.org/2001/XMLSchema#double"
+                            MustBePresent="true"
+                            Category="urn:baeldung:atm:withdrawal"
+                            AttributeId="urn:baeldung:atm:withdrawal:amount"/>
+                    </Apply>
+                    <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#double">500.00</AttributeValue>
+                </Apply>
+            </Apply>
+        </Condition>
+    </Rule>
+    <Rule RuleId="urn:oasis:names:tc:baeldung:WithDrawalPolicy:Rule2" Effect="Permit">
+        <Description>
+Permit withdrawals under $500 between 20:00 and 08:00
+        </Description>
+        <Target>
+            <AnyOf>
+                <AllOf>
+                    <Match MatchId="urn:oasis:names:tc:xacml:1.0:function:string-equal">
+                        <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">withdrawal</AttributeValue>
+                        <AttributeDesignator 
+                            DataType="http://www.w3.org/2001/XMLSchema#string" 
+                            MustBePresent="true" 
+                            Category="urn:oasis:names:tc:xacml:3.0:attribute-category:action" 
+                            AttributeId="urn:oasis:names:tc:xacml:1.0:action:action-id"/>
+                    </Match>
+                </AllOf>
+            </AnyOf>
+        </Target>
+        <Condition>
+            <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:and">
+                <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:not">
+                    <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:time-in-range">
+                        <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:time-one-and-only">
+                            <AttributeDesignator
+                                DataType="http://www.w3.org/2001/XMLSchema#time"
+                                MustBePresent="true"
+                                Category="urn:oasis:names:tc:xacml:3.0:attribute-category:environment"
+                                AttributeId="urn:oasis:names:tc:xacml:1.0:environment:current-time"/>
+                        </Apply>
+                        <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#time">08:00:00</AttributeValue>
+                        <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#time">20:00:00</AttributeValue>
+                    </Apply>
+                </Apply>
+                <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:double-less-than-or-equal">
+                    <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:double-one-and-only">
+                        <AttributeDesignator
+                            DataType="http://www.w3.org/2001/XMLSchema#double"
+                            MustBePresent="true"
+                            Category="urn:baeldung:atm:withdrawal"
+                            AttributeId="urn:baeldung:atm:withdrawal:amount"/>
+                    </Apply>
+                    <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#double">500.00</AttributeValue>
+                </Apply>
+            </Apply>
+        </Condition>
+    </Rule>
+    <Rule RuleId="urn:oasis:names:tc:baeldung:WithDrawalPolicy:Rule3" Effect="Permit">
+        <Description>
+Permit withdrawals of any value between 08:00 and 20:00
+        </Description>
+        <Target>
+            <AnyOf>
+                <AllOf>
+                    <Match MatchId="urn:oasis:names:tc:xacml:1.0:function:string-equal">
+                        <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">withdrawal</AttributeValue>
+                        <AttributeDesignator 
+                            DataType="http://www.w3.org/2001/XMLSchema#string" 
+                            MustBePresent="true" 
+                            Category="urn:oasis:names:tc:xacml:3.0:attribute-category:action" 
+                            AttributeId="urn:oasis:names:tc:xacml:1.0:action:action-id"/>
+                    </Match>
+                </AllOf>
+            </AnyOf>
+        </Target>
+        <Condition>
+            <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:time-in-range">
+                <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:time-one-and-only">
+                    <AttributeDesignator
+                        DataType="http://www.w3.org/2001/XMLSchema#time"
+                        MustBePresent="true"
+                        Category="urn:oasis:names:tc:xacml:3.0:attribute-category:environment"
+                        AttributeId="urn:oasis:names:tc:xacml:1.0:environment:current-time"/>
+                </Apply>
+                <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#time">08:00:00</AttributeValue>
+                <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#time">20:00:00</AttributeValue>
+            </Apply>
+        </Condition>
+    </Rule>
+    
+</Policy>

libraries-security/src/test/resources/xacml4j/Request.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Request 
+    xmlns="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17 http://docs.oasis-open.org/xacml/3.0/xacml-core-v3-schema-wd-17.xsd"
+    CombinedDecision="true"
+    ReturnPolicyIdList="false">
+    
+    <Attributes Category="urn:oasis:names:tc:xacml:3.0:attribute-category:action">
+        <Attribute 
+            IncludeInResult="false" 
+            AttributeId="urn:oasis:names:tc:xacml:3.0:attribute-category:action">
+            <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">withdrawal</AttributeValue>
+        </Attribute>
+    </Attributes>
+    <Attributes Category="urn:oasis:names:tc:xacml:3.0:attribute-category:action">
+        <Attribute 
+            IncludeInResult="false" 
+            AttributeId="urn:oasis:names:tc:xacml:1.0:environment:current-time">
+            <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#time">21:00:00</AttributeValue>
+        </Attribute>
+    </Attributes>
+    <Attributes Category="urn:baeldung:atm:withdrawal">
+        <Attribute 
+            IncludeInResult="false" 
+            AttributeId="urn:baeldung:atm:withdrawal:amount">
+            <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#decimal">1200</AttributeValue>
+        </Attribute>
+    </Attributes>
+</Request>

libraries-security/src/test/resources/xacml4j/Response.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Response xmlns="urn:oasis:names:tc:xacml:2.0:context:schema:os" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:oasis:names:tc:xacml:2.0:context:schema:os http://docs.oasis-open.org/xacml/access_control-xacml-2.0-context-schema-os.xsd">
+	<Result>
+		<Decision>NotApplicable</Decision>
+		<Status>
+			<StatusCode Value="urn:oasis:names:tc:xacml:1.0:status:ok"/>
+		</Status>
+	</Result>
+</Response>

libraries/pom.xml

@@ -40,6 +40,11 @@
             <artifactId>javatuples</artifactId>
             <version>${javatuples.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.javassist</groupId>
+            <artifactId>javassist</artifactId>
+            <version>${javaassist.version}</version>
+        </dependency>
         <!-- https://mvnrepository.com/artifact/org.assertj/assertj-core -->
         <dependency>
             <groupId>org.assertj</groupId>
@@ -51,42 +56,6 @@
             <artifactId>javers-core</artifactId>
             <version>${javers.version}</version>
         </dependency>
-        <dependency>
-            <groupId>net.serenity-bdd</groupId>
-            <artifactId>serenity-core</artifactId>
-            <version>${serenity.version}</version>
-            <scope>test</scope>
-            <exclusions>
-                <exclusion>
-                    <groupId>org.asciidoctor</groupId>
-                    <artifactId>asciidoctorj</artifactId>
-                </exclusion>
-            </exclusions>
-        </dependency>
-        <dependency>
-            <groupId>net.serenity-bdd</groupId>
-            <artifactId>serenity-junit</artifactId>
-            <version>${serenity.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>net.serenity-bdd</groupId>
-            <artifactId>serenity-jbehave</artifactId>
-            <version>${serenity.jbehave.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>net.serenity-bdd</groupId>
-            <artifactId>serenity-rest-assured</artifactId>
-            <version>${serenity.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>net.serenity-bdd</groupId>
-            <artifactId>serenity-jira-requirements-provider</artifactId>
-            <version>${serenity.jira.version}</version>
-            <scope>test</scope>
-        </dependency>
         <!-- JDO -->
         <dependency>
             <groupId>org.datanucleus</groupId>
@@ -139,30 +108,6 @@
             <artifactId>spring-web</artifactId>
             <version>${spring.version}</version>
         </dependency>
-        <dependency>
-            <groupId>net.serenity-bdd</groupId>
-            <artifactId>serenity-spring</artifactId>
-            <version>${serenity.version}</version>
-            <scope>test</scope>
-            <exclusions>
-                <exclusion>
-                    <groupId>org.springframework</groupId>
-                    <artifactId>spring-test</artifactId>
-                </exclusion>
-            </exclusions>
-        </dependency>
-        <dependency>
-            <groupId>net.serenity-bdd</groupId>
-            <artifactId>serenity-screenplay</artifactId>
-            <version>${serenity.version}</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>net.serenity-bdd</groupId>
-            <artifactId>serenity-screenplay-webdriver</artifactId>
-            <version>${serenity.version}</version>
-            <scope>test</scope>
-        </dependency>
         <!-- JetS3t -->
         <dependency>
             <groupId>org.lucee</groupId>
@@ -253,29 +198,6 @@
 
     <build>
         <plugins>
-            <plugin>
-                <artifactId>maven-failsafe-plugin</artifactId>
-                <version>${maven-failsafe-plugin.version}</version>
-                <configuration>
-                    <systemProperties>
-                        <webdriver.chrome.driver>chromedriver</webdriver.chrome.driver>
-                    </systemProperties>
-                </configuration>
-            </plugin>
-            <plugin>
-                <groupId>net.serenity-bdd.maven.plugins</groupId>
-                <artifactId>serenity-maven-plugin</artifactId>
-                <version>${serenity.plugin.version}</version>
-                <executions>
-                    <execution>
-                        <id>serenity-reports</id>
-                        <phase>post-integration-test</phase>
-                        <goals>
-                            <goal>aggregate</goal>
-                        </goals>
-                    </execution>
-                </executions>
-            </plugin>
             <!-- JDO Plugin -->
             <plugin>
                 <groupId>org.datanucleus</groupId>
@@ -380,6 +302,7 @@
         <spring.version>4.3.8.RELEASE</spring.version>
         <spring-mock-mvc.version>3.0.3</spring-mock-mvc.version>
         <quartz.version>2.3.0</quartz.version>
+        <javaassist.version>3.21.0-GA</javaassist.version>
         <jool.version>0.9.12</jool.version>
         <maven-jar-plugin.version>3.0.2</maven-jar-plugin.version>
         <commons-net.version>3.6</commons-net.version>

libraries/serenity.properties

@@ -1,4 +0,0 @@
-jira.url=<jira-url>
-jira.project=<jira-project>
-jira.username=<jira-username>
-jira.password=<jira-password>

maven-modules/maven-parent-pom-resolution/README.md

@@ -0,0 +1,3 @@
+### Relevant Articles:
+
+- [Understanding the "relativePath" Tag - Maven Parent POM Resolution At A Glance](https://www.baeldung.com/maven-relativepath)

maven-modules/maven-parent-pom-resolution/pom.xml

@@ -0,0 +1,28 @@
+<?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>
+    <groupId>com.baeldung</groupId>
+    <artifactId>maven-parent-pom-resolution</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>pom</packaging>
+
+    <modules>
+        <module>project-a</module>
+    </modules>
+
+    <!-- to detect the POM hierarchy, just type "mvn dependency:display-ancestors" -->
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-dependency-plugin</artifactId>
+                    <version>3.2.0</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
+</project>

maven-modules/maven-parent-pom-resolution/project-a/pom.xml

@@ -0,0 +1,20 @@
+<?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>project-a</artifactId>
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>maven-parent-pom-resolution</artifactId>
+        <version>1.0-SNAPSHOT</version>
+        <!-- The parent pom is resolved to ../pom.xml -->
+    </parent>
+    <packaging>pom</packaging>
+
+    <modules>
+        <module>project-b</module>
+        <module>project-c</module>
+    </modules>
+
+</project>

maven-modules/maven-parent-pom-resolution/project-a/project-b/pom.xml

@@ -0,0 +1,15 @@
+<?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>project-b</artifactId>
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>project-a</artifactId>
+        <version>1.0-SNAPSHOT</version>
+        <!-- The parent pom is resolved to project a's pom.xml -->
+    </parent>
+    <packaging>pom</packaging>
+
+</project>

maven-modules/maven-parent-pom-resolution/project-a/project-c/pom.xml

@@ -0,0 +1,20 @@
+<?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>project-c</artifactId>
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>project-b</artifactId>
+        <version>1.0-SNAPSHOT</version>
+        <relativePath>../project-b/pom.xml</relativePath>
+        <!-- The parent pom is resolved to project a's pom.xml -->
+    </parent>
+    <packaging>pom</packaging>
+
+    <modules>
+        <module>project-d</module>
+    </modules>
+
+</project>

maven-modules/maven-parent-pom-resolution/project-a/project-c/project-d/pom.xml

@@ -0,0 +1,17 @@
+<?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>project-d</artifactId>
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>project-a</artifactId>
+        <version>1.0-SNAPSHOT</version>
+        <!-- removing relativePath won't work even if project-a is the aggregator project -->
+        <!-- it only works in IntelliJ IDEA when project-a is registered as a Maven Project -->
+        <relativePath>../../pom.xml</relativePath>
+    </parent>
+    <packaging>pom</packaging>
+
+</project>

maven-modules/maven-properties/pom.xml

@@ -18,7 +18,7 @@
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
-            <version>4.13</version>
+	    <version>${junit.version}</version>
         </dependency>
     </dependencies>
 
@@ -46,6 +46,7 @@
     <properties>
         <name>${project.name}</name>
         <my.awesome.property>property-from-pom</my.awesome.property>
+        <junit.version>4.13</junit.version> 
     </properties>
 
 </project>

maven-modules/maven-surefire-plugin/README.md

@@ -0,0 +1,3 @@
+## Relevant Articles:
+
+- [Running a Single Test or Method With Maven](https://www.baeldung.com/maven-run-single-test)

maven-modules/pom.xml

@@ -36,6 +36,7 @@
         <module>host-maven-repo-example</module>
         <module>plugin-management</module>
         <module>maven-surefire-plugin</module>
+        <module>maven-parent-pom-resolution</module>
     </modules>
 
 </project>

parent-spring-5/pom.xml

@@ -30,7 +30,7 @@
     </dependencies>
 
     <properties>
-        <spring.version>5.3.7</spring.version>
+        <spring.version>5.3.9</spring.version>
         <spring-security.version>5.2.3.RELEASE</spring-security.version>
         <spring-boot-starter-test.version>1.5.10.RELEASE</spring-boot-starter-test.version>
     </properties>

patterns/design-patterns-architectural/README.md

@@ -3,3 +3,4 @@
 - [The DAO Pattern in Java](https://www.baeldung.com/java-dao-pattern)
 - [DAO vs Repository Patterns](https://www.baeldung.com/java-dao-vs-repository)
 - [Difference Between MVC and MVP Patterns](https://www.baeldung.com/mvc-vs-mvp-pattern)
+- [The DTO Pattern (Data Transfer Object)](https://www.baeldung.com/java-dto-pattern)

patterns/design-patterns-architectural/pom.xml

@@ -15,6 +15,21 @@
     </parent>
 
     <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+            <version>${spring-boot.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <version>${spring-boot.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.rest-assured</groupId>
+            <artifactId>rest-assured</artifactId>
+            <version>${rest-assured.version}</version>
+        </dependency>
         <dependency>
             <groupId>org.assertj</groupId>
             <artifactId>assertj-core</artifactId>
@@ -38,6 +53,9 @@
         <assertj-core.version>3.9.1</assertj-core.version>
         <hibernate-core.version>5.2.16.Final</hibernate-core.version>
         <mysql-connector.version>6.0.6</mysql-connector.version>
+        <spring-boot.version>2.5.3</spring-boot.version>
+        <rest-assured.version>3.3.0</rest-assured.version>
+
     </properties>
 
 </project>

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/Main.java

@@ -0,0 +1,12 @@
+package com.baeldung.dtopattern;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Main {
+    public static void main(String[] args) {
+        SpringApplication.run(Main.class, args);
+    }
+}
+

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/api/Mapper.java

@@ -0,0 +1,28 @@
+package com.baeldung.dtopattern.api;
+
+import com.baeldung.dtopattern.domain.Role;
+import com.baeldung.dtopattern.domain.User;
+import org.springframework.stereotype.Component;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static java.util.stream.Collectors.toList;
+
+@Component
+class Mapper {
+    public UserDTO toDto(User user) {
+        String name = user.getName();
+        List<String> roles = user
+                .getRoles()
+                .stream()
+                .map(Role::getName)
+                .collect(toList());
+
+        return new UserDTO(name, roles);
+    }
+
+    public User toUser(UserCreationDTO userDTO) {
+        return new User(userDTO.getName(), userDTO.getPassword(), new ArrayList<>());
+    }
+}

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/api/UserController.java

@@ -0,0 +1,51 @@
+package com.baeldung.dtopattern.api;
+
+import com.baeldung.dtopattern.domain.RoleService;
+import com.baeldung.dtopattern.domain.User;
+import com.baeldung.dtopattern.domain.UserService;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+import static java.util.stream.Collectors.toList;
+
+@RestController
+@RequestMapping("/users")
+class UserController {
+
+    private UserService userService;
+    private RoleService roleService;
+    private Mapper mapper;
+
+    public UserController(UserService userService,  RoleService roleService, Mapper mapper) {
+        this.userService = userService;
+        this.roleService = roleService;
+        this.mapper = mapper;
+    }
+
+    @GetMapping
+    @ResponseBody
+    public List<UserDTO> getUsers() {
+        return userService.getAll()
+            .stream()
+            .map(mapper::toDto)
+            .collect(toList());
+    }
+
+
+    @PostMapping
+    @ResponseBody
+    public UserIdDTO create(@RequestBody UserCreationDTO userDTO) {
+        User user = mapper.toUser(userDTO);
+
+        userDTO.getRoles()
+                .stream()
+                .map(role -> roleService.getOrCreate(role))
+                .forEach(user::addRole);
+
+        userService.save(user);
+
+        return new UserIdDTO(user.getId());
+    }
+
+}

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/api/UserCreationDTO.java

@@ -0,0 +1,36 @@
+package com.baeldung.dtopattern.api;
+
+import java.util.List;
+
+public class UserCreationDTO {
+
+    private String name;
+    private String password;
+    private List<String> roles;
+
+    UserCreationDTO() {}
+
+    public String getName() {
+        return name;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public List<String> getRoles() {
+        return roles;
+    }
+
+    void setName(String name) {
+        this.name = name;
+    }
+
+    void setPassword(String password) {
+        this.password = password;
+    }
+
+    void setRoles(List<String> roles) {
+        this.roles = roles;
+    }
+}

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/api/UserDTO.java

@@ -0,0 +1,22 @@
+package com.baeldung.dtopattern.api;
+
+import java.util.List;
+
+public class UserDTO {
+    private String name;
+    private List<String> roles;
+
+    public UserDTO(String name, List<String> roles) {
+        this.name = name;
+        this.roles = roles;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public List<String> getRoles() {
+        return roles;
+    }
+
+}

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/api/UserIdDTO.java

@@ -0,0 +1,14 @@
+package com.baeldung.dtopattern.api;
+
+public class UserIdDTO {
+
+    private String id;
+
+    public UserIdDTO(String id) {
+        this.id = id;
+    }
+
+    public String getId() {
+        return id;
+    }
+}

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/domain/InMemoryRepository.java

@@ -0,0 +1,49 @@
+package com.baeldung.dtopattern.domain;
+
+import org.springframework.stereotype.Service;
+
+import java.util.*;
+
+@Service
+class InMemoryRepository implements UserRepository, RoleRepository {
+
+    private Map<String, User> users = new LinkedHashMap<>();
+    private Map<String, Role> roles = new LinkedHashMap<>();
+
+    @Override
+    public List<User> getAll() {
+        return new ArrayList<>(users.values());
+    }
+
+    @Override
+    public void save(User user) {
+        user.setId(UUID.randomUUID().toString());
+        users.put(user.getId(), user);
+    }
+
+    @Override
+    public void save(Role role) {
+        role.setId(UUID.randomUUID().toString());
+        roles.put(role.getId(), role);
+    }
+
+    @Override
+    public Role getRoleById(String id) {
+        return roles.get(id);
+    }
+
+    @Override
+    public Role getRoleByName(String name) {
+        return roles.values()
+            .stream()
+            .filter(role -> role.getName().equalsIgnoreCase(name))
+            .findFirst()
+            .orElse(null);
+    }
+
+    @Override
+    public void deleteAll() {
+        users.clear();
+        roles.clear();
+    }
+}

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/domain/Role.java

@@ -0,0 +1,28 @@
+package com.baeldung.dtopattern.domain;
+
+import java.util.Objects;
+
+public class Role {
+    private String id;
+    private String name;
+
+    public Role(String name) {
+        this.name = Objects.requireNonNull(name);
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    void setId(String id) {
+        this.id = Objects.requireNonNull(id);
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = Objects.requireNonNull(name);
+    }
+}

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/domain/RoleRepository.java

@@ -0,0 +1,7 @@
+package com.baeldung.dtopattern.domain;
+
+public interface RoleRepository {
+    Role getRoleById(String id);
+    Role getRoleByName(String name);
+    void save(Role role);
+}

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/domain/RoleService.java

@@ -0,0 +1,32 @@
+package com.baeldung.dtopattern.domain;
+
+import org.springframework.stereotype.Service;
+
+import java.util.Objects;
+
+@Service
+public class RoleService {
+
+    private RoleRepository repository;
+
+    public RoleService(RoleRepository repository) {
+        this.repository = repository;
+    }
+
+    public Role getOrCreate(String name) {
+        Role role = repository.getRoleByName(name);
+
+        if (role == null) {
+            role = new Role(name);
+            repository.save(role);
+        }
+
+        return role;
+    }
+
+    public void save(Role role) {
+        Objects.requireNonNull(role);
+        repository.save(role);
+    }
+
+}

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/domain/User.java

@@ -0,0 +1,80 @@
+package com.baeldung.dtopattern.domain;
+
+import javax.crypto.*;
+import javax.crypto.spec.SecretKeySpec;
+import java.nio.charset.StandardCharsets;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+
+public class User {
+
+    private static SecretKeySpec KEY = initKey();
+
+    static SecretKeySpec initKey(){
+        try {
+            SecretKey secretKey = KeyGenerator.getInstance("AES").generateKey();
+            return new SecretKeySpec(secretKey.getEncoded(), "AES");
+        } catch (NoSuchAlgorithmException ex) {
+            return null;
+        }
+    }
+
+    private String id;
+    private String name;
+    private String password;
+    private List<Role> roles;
+
+    public User(String name, String password, List<Role> roles) {
+        this.name = Objects.requireNonNull(name);
+        this.password = this.encrypt(password);
+        this.roles = Objects.requireNonNull(roles);
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public void addRole(Role role) {
+        roles.add(role);
+    }
+
+    public List<Role> getRoles() {
+        return Collections.unmodifiableList(roles);
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    void setId(String id) {
+        this.id = id;
+    }
+
+    String encrypt(String password) {
+        Objects.requireNonNull(password);
+        try {
+            Cipher cipher = Cipher.getInstance("AES");
+            cipher.init(Cipher.ENCRYPT_MODE, KEY);
+            final byte[] encryptedBytes = cipher.doFinal(password.getBytes(StandardCharsets.UTF_8));
+            return new String(encryptedBytes, StandardCharsets.UTF_8);
+        } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | IllegalBlockSizeException | BadPaddingException e) {
+            // do nothing
+            return "";
+        }
+    }
+}

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/domain/UserRepository.java

@@ -0,0 +1,9 @@
+package com.baeldung.dtopattern.domain;
+
+import java.util.List;
+
+public interface UserRepository {
+    List<User> getAll();
+    void save(User user);
+    void deleteAll();
+}

patterns/design-patterns-architectural/src/main/java/com/baeldung/dtopattern/domain/UserService.java

@@ -0,0 +1,25 @@
+package com.baeldung.dtopattern.domain;
+
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+import java.util.Objects;
+
+@Service
+public class UserService {
+
+    private UserRepository repository;
+
+    public UserService(UserRepository repository) {
+        this.repository = repository;
+    }
+
+    public List<User> getAll() {
+        return repository.getAll();
+    }
+
+    public void save(User user) {
+        Objects.requireNonNull(user);
+        repository.save(user);
+    }
+}

patterns/design-patterns-architectural/src/test/java/com/baeldung/dtopattern/api/MapperUnitTest.java

@@ -0,0 +1,56 @@
+package com.baeldung.dtopattern.api;
+
+import com.baeldung.dtopattern.domain.Role;
+import com.baeldung.dtopattern.domain.User;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class MapperUnitTest {
+
+    @Test
+    void toDto_shouldMapFromDomainToDTO() {
+        String name = "Test";
+        String password = "test";
+        Role admin = new Role("admin");
+        List<String> expectedRoles = Collections.singletonList("admin");
+
+        List<Role> roles = new ArrayList<>();
+        roles.add(admin);
+
+        User user = new User(name, password, roles);
+        Mapper mapper = new Mapper();
+
+        UserDTO dto = mapper.toDto(user);
+
+        assertEquals(name, dto.getName());
+        assertEquals(expectedRoles, dto.getRoles());
+    }
+
+    @Test
+    void toUser_shouldMapFromDTOToDomain() {
+        String name = "Test";
+        String password = "test";
+        String role = "admin";
+
+        UserCreationDTO dto = new UserCreationDTO();
+        dto.setName(name);
+        dto.setPassword(password);
+        dto.setRoles(Collections.singletonList("admin"));
+
+        User expectedUser = new User(name, password, new ArrayList<>());
+
+        Mapper mapper = new Mapper();
+
+        User user = mapper.toUser(dto);
+
+        assertEquals(name, user.getName());
+        assertEquals(expectedUser.getPassword(), user.getPassword());
+        assertEquals(Collections.emptyList(), user.getRoles());
+    }
+
+}

patterns/design-patterns-architectural/src/test/java/com/baeldung/dtopattern/api/UserControllerIntegrationTest.java

@@ -0,0 +1,80 @@
+package com.baeldung.dtopattern.api;
+
+import com.baeldung.dtopattern.domain.Role;
+import com.baeldung.dtopattern.domain.RoleRepository;
+import com.baeldung.dtopattern.domain.User;
+import com.baeldung.dtopattern.domain.UserRepository;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import io.restassured.http.ContentType;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.boot.web.server.LocalServerPort;
+
+import java.util.Collections;
+
+import static io.restassured.RestAssured.given;
+import static org.hamcrest.CoreMatchers.*;
+import static org.springframework.http.HttpStatus.OK;
+
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+class UserControllerIntegrationTest {
+
+    @Autowired
+    private TestRestTemplate restTemplate;
+
+    @Autowired
+    private UserRepository userRepository;
+
+    @Autowired
+    private RoleRepository roleRepository;
+
+    @LocalServerPort
+    int port;
+
+    @Autowired
+    private ObjectMapper objectMapper;
+
+    @Test
+    void create_shouldReturnUseId() throws Exception {
+        UserCreationDTO request = new UserCreationDTO();
+        request.setName("User 1");
+        request.setPassword("Test@123456");
+        request.setRoles(Collections.singletonList("admin"));
+
+        given()
+            .contentType(ContentType.JSON)
+            .body(objectMapper.writeValueAsString(request))
+        .when()
+            .port(port)
+            .post("/users")
+        .then()
+            .statusCode(OK.value())
+            .body("id", notNullValue());
+    }
+
+    @Test
+    void getAll_shouldReturnUseDTO() {
+
+        userRepository.deleteAll();
+
+        String roleName = "admin";
+        Role admin = new Role(roleName);
+        roleRepository.save(admin);
+
+        String name = "User 1";
+        User user = new User(name, "Test@123456", Collections.singletonList(admin));
+        userRepository.save(user);
+
+        given()
+            .port(port)
+        .when()
+            .get("/users")
+        .then()
+            .statusCode(OK.value())
+            .body("size()", is(1))
+            .body("[0].name", equalTo(name))
+            .body("[0].roles", hasItem(roleName));
+    }
+}

patterns/design-patterns-architectural/src/test/java/com/baeldung/dtopattern/domain/InMemoryRepositoryUnitTest.java

@@ -0,0 +1,83 @@
+package com.baeldung.dtopattern.domain;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+class InMemoryRepositoryUnitTest {
+
+    @Test
+    void getAll_shouldReturnAllUsers() {
+
+        String name = "Test";
+        String password = "test123";
+        List<Role> roles = new ArrayList<>();
+
+        User user = new User(name, password, roles);
+        List<User> expectedUsers = Collections.singletonList(user);
+
+        InMemoryRepository repository = new InMemoryRepository();
+        repository.save(user);
+
+        List<User> users = repository.getAll();
+
+        assertEquals(expectedUsers, users);
+    }
+
+    @Test
+    void save_whenSavingUser_shouldSetId() {
+        String name = "Test";
+        String password = "test123";
+        List<Role> roles = new ArrayList<>();
+
+        User user = new User(name, password, roles);
+
+        InMemoryRepository repository = new InMemoryRepository();
+        repository.save(user);
+
+        assertNotNull(user.getId());
+    }
+
+    @Test
+    void save_whenSavingRole_shouldSetId() {
+        String name = "Test";
+        Role role = new Role(name);
+
+        InMemoryRepository repository = new InMemoryRepository();
+        repository.save(role);
+
+        assertNotNull(role.getId());
+    }
+
+    @Test
+    void getRoleById_shouldReturnRoleById() {
+        String name = "Test";
+        Role expectedRole = new Role(name);
+
+        InMemoryRepository repository = new InMemoryRepository();
+        repository.save(expectedRole);
+
+        Role role = repository.getRoleById(expectedRole.getId());
+
+        assertEquals(expectedRole, role);
+    }
+
+    @Test
+    void getRoleByName_shouldReturnRoleByName() {
+        String name = "Test";
+        Role expectedRole = new Role(name);
+
+        InMemoryRepository repository = new InMemoryRepository();
+        repository.save(expectedRole);
+
+        Role role = repository.getRoleByName(name);
+
+        assertEquals(expectedRole, role);
+    }
+
+}

patterns/design-patterns-architectural/src/test/java/com/baeldung/dtopattern/domain/UserUnitTest.java

@@ -0,0 +1,38 @@
+package com.baeldung.dtopattern.domain;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class UserUnitTest {
+
+
+    @Test
+    void whenUserIsCreated_shouldEncryptPassword() {
+        User user = new User("Test", "test", new ArrayList<>());
+
+        assertEquals(user.encrypt("test"), user.getPassword());
+        assertNotEquals(user.encrypt("Test"), user.getPassword());
+    }
+
+    @Test
+    void whenUserIsCreated_shouldFailIfNameIsNull() {
+        assertThrows(NullPointerException.class, () ->
+            new User(null, "test", new ArrayList<>()));
+    }
+
+    @Test
+    void whenUserIsCreated_shouldFailIfPasswordIsNull() {
+        assertThrows(NullPointerException.class, () ->
+            new User("Test", null, new ArrayList<>()));
+    }
+
+    @Test
+    void whenUserIsCreated_shouldFailIfRolesIsNull() {
+        assertThrows(NullPointerException.class, () ->
+            new User("Test", "Test", null));
+    }
+
+}

persistence-modules/java-jpa-3/README.md

@@ -13,3 +13,4 @@ This module contains articles about the Java Persistence API (JPA) in Java.
 - [Returning an Auto-Generated Id with JPA](https://www.baeldung.com/jpa-get-auto-generated-id)
 - [How to Return Multiple Entities In JPA Query](https://www.baeldung.com/jpa-return-multiple-entities)
 - [Defining Unique Constraints in JPA](https://www.baeldung.com/jpa-unique-constraints)
+- [How to Check Field Existence in MongoDB?](https://www.baeldung.com/mongodb-check-field-exists)

reactor-core/README.md

@@ -11,3 +11,4 @@ This module contains articles about Reactor Core.
 - [How to Convert Mono<List<T\>> Into Flux<T\>](https://www.baeldung.com/java-mono-list-to-flux)
 - [Project Reactor: map() vs flatMap()](https://www.baeldung.com/java-reactor-map-flatmap)
 - [What Does Mono.defer() Do?](https://www.baeldung.com/java-mono-defer)
+- [Handling Exceptions in Project Reactor](https://www.baeldung.com/reactor-exceptions)

reactor-core/pom.xml

@@ -41,7 +41,7 @@
     </dependencies>
 
     <properties>
-        <reactor.version>3.3.9.RELEASE</reactor.version>
+        <reactor.version>3.4.9</reactor.version>
         <assertj.version>3.6.1</assertj.version>
     </properties>
 

reactor-core/src/test/java/com/baeldung/reactor/exception/ExceptionUnitTest.java

@@ -0,0 +1,89 @@
+package com.baeldung.reactor.exception;
+
+import org.junit.Test;
+import org.reactivestreams.Publisher;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.core.publisher.SynchronousSink;
+import reactor.test.StepVerifier;
+
+import java.util.function.BiConsumer;
+import java.util.function.Function;
+
+public class ExceptionUnitTest {
+    @Test
+    public void givenInvalidElement_whenPipelineThrowsException_thenErrorIsSentDownstream() {
+        Function<String, Integer> mapper = input -> {
+            if (input.matches("\\D")) {
+                throw new NumberFormatException();
+            } else {
+                return Integer.parseInt(input);
+            }
+        };
+
+        Flux<String> inFlux = Flux.just("1", "1.5", "2");
+        Flux<Integer> outFlux = inFlux.map(mapper);
+
+        StepVerifier.create(outFlux)
+                .expectNext(1)
+                .expectError(NumberFormatException.class)
+                .verify();
+    }
+
+    @Test
+    public void givenInvalidElement_whenHandleCallsSinkErrorMethod_thenErrorIsSentDownstream() {
+        BiConsumer<String, SynchronousSink<Integer>> handler = (input, sink) -> {
+            if (input.matches("\\D")) {
+                sink.error(new NumberFormatException());
+            } else {
+                sink.next(Integer.parseInt(input));
+            }
+        };
+
+        Flux<String> inFlux = Flux.just("1", "1.5", "2");
+        Flux<Integer> outFlux = inFlux.handle(handler);
+
+        StepVerifier.create(outFlux)
+                .expectNext(1)
+                .expectError(NumberFormatException.class)
+                .verify();
+    }
+
+    @Test
+    public void givenInvalidElement_whenFlatMapCallsMonoErrorMethod_thenErrorIsSentDownstream() {
+        Function<String, Publisher<Integer>> mapper = input -> {
+            if (input.matches("\\D")) {
+                return Mono.error(new NumberFormatException());
+            } else {
+                return Mono.just(Integer.parseInt(input));
+            }
+        };
+
+        Flux<String> inFlux = Flux.just("1", "1.5", "2");
+        Flux<Integer> outFlux = inFlux.flatMap(mapper);
+
+        StepVerifier.create(outFlux)
+                .expectNext(1)
+                .expectError(NumberFormatException.class)
+                .verify();
+    }
+
+    @Test
+    public void givenNullElement_whenPipelineOperatorExecutes_thenNpeIsSentDownstream() {
+        Function<String, Integer> mapper = input -> {
+            if (input == null) {
+                return 0;
+            } else {
+                return Integer.parseInt(input);
+            }
+        };
+
+        Flux<String> inFlux = Flux.just("1", null, "2");
+        Flux<Integer> outFlux = inFlux.map(mapper);
+
+        StepVerifier.create(outFlux)
+                .expectNext(1)
+                .expectError(NullPointerException.class)
+                .verify();
+    }
+}

spring-kafka/README.md

@@ -8,6 +8,7 @@ This module contains articles about Spring with Kafka
 - [Testing Kafka and Spring Boot](https://www.baeldung.com/spring-boot-kafka-testing)
 - [Monitor the Consumer Lag in Apache Kafka](https://www.baeldung.com/java-kafka-consumer-lag)
 - [Send Large Messages With Kafka](https://www.baeldung.com/java-kafka-send-large-message)
+- [Configuring Kafka SSL Using Spring Boot](https://www.baeldung.com/spring-boot-kafka-ssl)
 
 ### Intro
 

spring-kafka/pom.xml

@@ -28,6 +28,10 @@
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.springframework.kafka</groupId>
             <artifactId>spring-kafka-test</artifactId>
@@ -41,9 +45,15 @@
             <scope>test</scope>
         </dependency>
         <dependency>
-            <groupId>commons-collections</groupId>
+            <groupId>org.testcontainers</groupId>
-            <artifactId>commons-collections</artifactId>
+            <artifactId>junit-jupiter</artifactId>
-            <version>3.2.1</version>
+            <version>${testcontainers-kafka.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.awaitility</groupId>
+            <artifactId>awaitility</artifactId>
+            <scope>test</scope>
         </dependency>
     </dependencies>
 

spring-kafka/src/main/java/com/baeldung/kafka/ssl/KafkaConsumer.java

@@ -0,0 +1,25 @@
+package com.baeldung.kafka.ssl;
+
+import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.springframework.kafka.annotation.KafkaListener;
+import org.springframework.stereotype.Component;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@Component
+@Slf4j
+public class KafkaConsumer {
+
+    public static final String TOPIC = "test-topic";
+
+    public final List<String> messages = new ArrayList<>();
+
+    @KafkaListener(topics = TOPIC)
+    public void receive(ConsumerRecord<String, String> consumerRecord) {
+        log.info("Received payload: '{}'", consumerRecord.toString());
+        messages.add(consumerRecord.value());
+    }
+
+}

spring-kafka/src/main/java/com/baeldung/kafka/ssl/KafkaProducer.java

@@ -0,0 +1,23 @@
+package com.baeldung.kafka.ssl;
+
+import lombok.AllArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.stereotype.Component;
+
+@Slf4j
+@AllArgsConstructor
+@Component
+public class KafkaProducer {
+
+    private final KafkaTemplate<String, String> kafkaTemplate;
+
+    public void sendMessage(String message, String topic) {
+        log.info("Producing message: {}", message);
+        kafkaTemplate.send(topic, "key", message)
+          .addCallback(
+            result -> log.info("Message sent to topic: {}", message),
+            ex -> log.error("Failed to send message", ex)
+          );
+    }
+}

spring-kafka/src/main/java/com/baeldung/kafka/ssl/KafkaSslApplication.java

@@ -0,0 +1,15 @@
+package com.baeldung.kafka.ssl;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+@EnableAutoConfiguration
+public class KafkaSslApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(KafkaSslApplication.class, args);
+    }
+
+}

spring-kafka/src/main/resources/application-ssl.yml

@@ -0,0 +1,18 @@
+spring:
+  kafka:
+    security:
+      protocol: "SSL"
+    bootstrap-servers: localhost:9093
+    ssl:
+      trust-store-location: classpath:/client-certs/kafka.client.truststore.jks
+      trust-store-password: password
+      key-store-location:  classpath:/client-certs/kafka.client.keystore.jks
+      key-store-password: password
+    consumer:
+      group-id: demo-group-id
+      auto-offset-reset: earliest
+      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
+      value-deserializer: org.apache.kafka.common.serialization.StringDeserializer
+    producer:
+      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
+      value-deserializer: org.apache.kafka.common.serialization.StringDeserializer

spring-kafka/src/test/java/com/baeldung/kafka/ssl/KafkaSslApplicationLiveTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.kafka.ssl;
+
+import lombok.extern.slf4j.Slf4j;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.ActiveProfiles;
+import org.testcontainers.containers.DockerComposeContainer;
+import org.testcontainers.containers.wait.strategy.Wait;
+import org.testcontainers.junit.jupiter.Container;
+import org.testcontainers.junit.jupiter.Testcontainers;
+
+import java.io.File;
+import java.time.Duration;
+import java.util.UUID;
+
+import static com.baeldung.kafka.ssl.KafkaConsumer.TOPIC;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.awaitility.Awaitility.await;
+
+@Slf4j
+@ActiveProfiles("ssl")
+@Testcontainers
+@SpringBootTest(classes = KafkaSslApplication.class)
+class KafkaSslApplicationLiveTest {
+
+    private static final File KAFKA_COMPOSE_FILE = new File("src/test/resources/docker/docker-compose.yml");
+    private static final String KAFKA_SERVICE = "kafka";
+    private static final int SSL_PORT = 9093;
+
+    @Container
+    public DockerComposeContainer<?> container =
+      new DockerComposeContainer<>(KAFKA_COMPOSE_FILE)
+        .withExposedService(KAFKA_SERVICE, SSL_PORT, Wait.forListeningPort());
+
+    @Autowired
+    private KafkaProducer kafkaProducer;
+
+    @Autowired
+    private KafkaConsumer kafkaConsumer;
+
+    @Test
+    void givenSslIsConfigured_whenProducerSendsMessageOverSsl_thenConsumerReceivesOverSsl() {
+        String message = generateSampleMessage();
+        kafkaProducer.sendMessage(message, TOPIC);
+
+        await().atMost(Duration.ofMinutes(2))
+          .untilAsserted(() -> assertThat(kafkaConsumer.messages).containsExactly(message));
+    }
+
+    private static String generateSampleMessage() {
+        return UUID.randomUUID().toString();
+    }
+}

spring-kafka/src/test/resources/docker/certs/kafka_keystore_credentials

@@ -0,0 +1 @@
+password

spring-kafka/src/test/resources/docker/certs/kafka_sslkey_credentials

@@ -0,0 +1 @@
+password

spring-kafka/src/test/resources/docker/certs/kafka_truststore_credentials

@@ -0,0 +1 @@
+password

spring-kafka/src/test/resources/docker/docker-compose.yml

@@ -0,0 +1,30 @@
+---
+version: '2'
+services:
+  zookeeper:
+    image: confluentinc/cp-zookeeper:6.2.0
+    environment:
+      ZOOKEEPER_CLIENT_PORT: 2181
+      ZOOKEEPER_TICK_TIME: 2000
+
+  kafka:
+    image: confluentinc/cp-kafka:6.2.0
+    depends_on:
+      - zookeeper
+    ports:
+      - 9092:9092
+      - 9093:9093
+    environment:
+      KAFKA_BROKER_ID: 1
+      KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
+      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://localhost:9092,SSL://localhost:9093
+      KAFKA_AUTO_CREATE_TOPICS_ENABLE: 'true'
+      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
+      KAFKA_SSL_CLIENT_AUTH: "required"
+      KAFKA_SSL_KEYSTORE_FILENAME: '/certs/kafka.server.keystore.jks'
+      KAFKA_SSL_KEYSTORE_CREDENTIALS: '/certs/kafka_keystore_credentials'
+      KAFKA_SSL_KEY_CREDENTIALS: '/certs/kafka_sslkey_credentials'
+      KAFKA_SSL_TRUSTSTORE_FILENAME: '/certs/kafka.server.truststore.jks'
+      KAFKA_SSL_TRUSTSTORE_CREDENTIALS: '/certs/kafka_truststore_credentials'
+    volumes:
+      - ./certs/:/etc/kafka/secrets/certs