Merge branch 'master' into master

core-groovy/README.md

@@ -4,3 +4,7 @@
 
 - [JDBC with Groovy](http://www.baeldung.com/jdbc-groovy)
 - [Working with JSON in Groovy](http://www.baeldung.com/groovy-json)
+- [Reading a File in Groovy](https://www.baeldung.com/groovy-file-read)
+- [Types of Strings in Groovy](https://www.baeldung.com/groovy-strings)
+- [A Quick Guide to Iterating a Map in Groovy](https://www.baeldung.com/groovy-map-iterating)
+- [An Introduction to Traits in Groovy](https://www.baeldung.com/groovy-traits)

core-groovy/pom.xml

@@ -23,6 +23,12 @@
             <groupId>org.codehaus.groovy</groupId>
             <artifactId>groovy-all</artifactId>
             <version>${groovy-all.version}</version>
+            <type>pom</type>
+        </dependency>
+        <dependency>
+            <groupId>org.codehaus.groovy</groupId>
+            <artifactId>groovy-dateutil</artifactId>
+            <version>${groovy.version}</version>
         </dependency>
         <dependency>
             <groupId>org.codehaus.groovy</groupId>
@@ -103,9 +109,12 @@
 
     <properties>
         <junit.platform.version>1.0.0</junit.platform.version>
-        <groovy.version>2.4.13</groovy.version>
-        <groovy-all.version>2.4.13</groovy-all.version>
-        <groovy-sql.version>2.4.13</groovy-sql.version>
+<!--         <groovy.version>2.4.13</groovy.version> -->
+<!--         <groovy-all.version>2.4.13</groovy-all.version> -->
+<!--         <groovy-sql.version>2.4.13</groovy-sql.version> -->
+        <groovy.version>2.5.6</groovy.version>
+        <groovy-all.version>2.5.6</groovy-all.version>
+        <groovy-sql.version>2.5.6</groovy-sql.version>
         <hsqldb.version>2.4.0</hsqldb.version>
         <spock-core.version>1.1-groovy-2.4</spock-core.version>
         <gmavenplus-plugin.version>1.6</gmavenplus-plugin.version>

core-groovy/src/test/groovy/com/baeldung/date/DateTest.groovy

@@ -0,0 +1,57 @@
+package com.baeldung.groovy.sql
+
+import static org.junit.Assert.*
+import java.util.Calendar.*
+import java.time.LocalDate 
+import java.text.SimpleDateFormat 
+import org.junit.Test
+
+
+class DateTest {
+
+    def dateStr = "2019-02-28"
+    def pattern = "yyyy-MM-dd"  
+
+    @Test
+    void whenGetStringRepresentation_thenCorrectlyConvertIntoDate() {
+        def dateFormat = new SimpleDateFormat(pattern)
+        def date = dateFormat.parse(dateStr)
+                
+        println("       String to Date with DateFormatter : " + date)
+
+        def cal = new GregorianCalendar();
+        cal.setTime(date);
+
+        assertEquals(cal.get(Calendar.YEAR),2019)
+        assertEquals(cal.get(Calendar.DAY_OF_MONTH),28)
+        assertEquals(cal.get(Calendar.MONTH),java.util.Calendar.FEBRUARY)
+    }
+
+    @Test
+    void whenGetStringRepresentation_thenCorrectlyConvertWithDateUtilsExtension() {
+    
+        def date = Date.parse(pattern, dateStr)
+                
+        println("       String to Date with Date.parse : " + date)
+    
+        def cal = new GregorianCalendar();
+        cal.setTime(date);
+
+        assertEquals(cal.get(Calendar.YEAR),2019)
+        assertEquals(cal.get(Calendar.DAY_OF_MONTH),28)
+        assertEquals(cal.get(Calendar.MONTH),java.util.Calendar.FEBRUARY)
+    }    
+
+    @Test
+    void whenGetStringRepresentation_thenCorrectlyConvertIntoDateWithLocalDate() {
+        def date = LocalDate.parse(dateStr, pattern)
+
+        println("       String to Date with LocalDate     : " + date)
+
+        assertEquals(date.getYear(),2019)
+        assertEquals(date.getMonth(),java.time.Month.FEBRUARY)
+        assertEquals(date.getDayOfMonth(),28)
+    }
+
+
+}

core-java-8/README.md

@@ -38,3 +38,4 @@
 - [Java @SafeVarargs Annotation](https://www.baeldung.com/java-safevarargs)
 - [Java @Deprecated Annotation](https://www.baeldung.com/java-deprecated)
 - [Java 8 Predicate Chain](https://www.baeldung.com/java-predicate-chain)
+- [Method References in Java](https://www.baeldung.com/java-method-references)

core-java-9/README.md

@@ -27,3 +27,5 @@
 - [Java 9 Platform Logging API](https://www.baeldung.com/java-9-logging-api)
 - [Guide to java.lang.Process API](https://www.baeldung.com/java-process-api)
 - [Immutable Set in Java](https://www.baeldung.com/java-immutable-set)
+- [Multi-Release Jar Files](https://www.baeldung.com/java-multi-release-jar)
+- [Ahead of Time Compilation (AoT)](https://www.baeldung.com/ahead-of-time-compilation)

core-java-collections-list/README.md

@@ -28,3 +28,5 @@
 - [Intersection of Two Lists in Java](https://www.baeldung.com/java-lists-intersection)
 - [Multi Dimensional ArrayList in Java](https://www.baeldung.com/java-multi-dimensional-arraylist)
 - [Determine If All Elements Are the Same in a Java List](https://www.baeldung.com/java-list-all-equal)
+- [List of Primitive Integer Values in Java](https://www.baeldung.com/java-list-primitive-int)
+- [Performance Comparison of Primitive Lists in Java](https://www.baeldung.com/java-list-primitive-performance)

core-java-collections/README.md

@@ -32,3 +32,4 @@
 - [A Guide to Iterator in Java](http://www.baeldung.com/java-iterator)
 - [Differences Between HashMap and Hashtable](https://www.baeldung.com/hashmap-hashtable-differences)
 - [Java ArrayList vs Vector](https://www.baeldung.com/java-arraylist-vs-vector)
+- [Defining a Char Stack in Java](https://www.baeldung.com/java-char-stack)

core-java-collections/src/main/java/com/baeldung/java/sort/CollectionsSortCompare.java

@@ -0,0 +1,39 @@
+package com.baeldung.java.sort;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+public class CollectionsSortCompare {
+
+    public static void main(String[] args) {
+        sortPrimitives();
+        sortReferenceType();
+        sortCollection();
+    }
+
+    private static void sortReferenceType() {
+        Integer[] numbers = {5, 22, 10, 0};
+        Arrays.sort(numbers);
+        System.out.println(Arrays.toString(numbers));
+    }
+
+    private static void sortCollection() {
+        List<Integer> numbersList = new ArrayList<>();
+        numbersList.add(5);
+        numbersList.add(22);
+        numbersList.add(10);
+        numbersList.add(0);
+
+        Collections.sort(numbersList);
+
+        numbersList.forEach(System.out::print);
+    }
+
+    private static void sortPrimitives() {
+        int[] numbers = {5, 22, 10, 0};
+        Arrays.sort(numbers);
+        System.out.println(Arrays.toString(numbers));
+    }
+}

core-java-collections/src/main/java/com/baeldung/performance/ArraySortBenchmark.java

@@ -0,0 +1,47 @@
+package com.baeldung.performance;
+
+import org.openjdk.jmh.annotations.*;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.SingleShotTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@Measurement(batchSize = 100000, iterations = 10)
+@Warmup(batchSize = 100000, iterations = 10)
+public class ArraySortBenchmark {
+
+    @State(Scope.Thread)
+    public static class Initialize {
+        Integer[] numbers = {5, 22, 10, 0};
+        int[] primitives = {5, 22, 10, 0};
+    }
+
+    @Benchmark
+    public Integer[] benchmarkArraysIntegerSort(ArraySortBenchmark.Initialize state) {
+        Arrays.sort(state.numbers);
+        return state.numbers;
+    }
+
+    @Benchmark
+    public int[] benchmarkArraysIntSort(ArraySortBenchmark.Initialize state) {
+        Arrays.sort(state.primitives);
+        return state.primitives;
+    }
+
+
+    public static void main(String[] args) throws Exception {
+        Options options = new OptionsBuilder()
+                .include(ArraySortBenchmark.class.getSimpleName()).threads(1)
+                .forks(1).shouldFailOnError(true)
+                .shouldDoGC(true)
+                .jvmArgs("-server").build();
+        new Runner(options).run();
+    }
+}

core-java-lang-oop/README.md

@@ -22,3 +22,4 @@
 - [Inheritance and Composition (Is-a vs Has-a relationship) in Java](http://www.baeldung.com/java-inheritance-composition)
 - [A Guide to Constructors in Java](https://www.baeldung.com/java-constructors)
 - [Java equals() and hashCode() Contracts](https://www.baeldung.com/java-equals-hashcode-contracts)
+- [Marker Interfaces in Java](https://www.baeldung.com/java-marker-interfaces)

core-java-lang/README.md

@@ -41,3 +41,4 @@
 - [Java Interfaces](https://www.baeldung.com/java-interfaces)
 - [Attaching Values to Java Enum](https://www.baeldung.com/java-enum-values)
 - [Variable Scope in Java](https://www.baeldung.com/java-variable-scope)
+- [Java Classes and Objects](https://www.baeldung.com/java-classes-objects)

core-java-networking/README.md

@@ -14,3 +14,4 @@
 - [A Guide to Java Sockets](http://www.baeldung.com/a-guide-to-java-sockets)
 - [Guide to Java URL Encoding/Decoding](http://www.baeldung.com/java-url-encoding-decoding)
 - [Do a Simple HTTP Request in Java](http://www.baeldung.com/java-http-request)
+- [Difference between URL and URI](http://www.baeldung.com/java-url-vs-uri)

core-java/README.md

@@ -19,7 +19,6 @@
 - [Introduction to Java Serialization](http://www.baeldung.com/java-serialization)
 - [Guide to UUID in Java](http://www.baeldung.com/java-uuid)
 - [Guide to Escaping Characters in Java RegExps](http://www.baeldung.com/java-regexp-escape-char)
-- [Difference between URL and URI](http://www.baeldung.com/java-url-vs-uri)
 - [Creating a Java Compiler Plugin](http://www.baeldung.com/java-build-compiler-plugin)
 - [Quick Guide to Java Stack](http://www.baeldung.com/java-stack)
 - [Compiling Java *.class Files with javac](http://www.baeldung.com/javac)
@@ -51,3 +50,4 @@
 - [Using Curl in Java](https://www.baeldung.com/java-curl)
 - [Finding Leap Years in Java](https://www.baeldung.com/java-leap-year)
 - [Java Bitwise Operators](https://www.baeldung.com/java-bitwise-operators)
+- [Guide to Creating and Running a Jar File in Java](https://www.baeldung.com/java-create-jar)

core-java/src/main/java/com/baeldung/urlconnection/PostJSONWithHttpURLConnection.java

@@ -0,0 +1,46 @@
+package com.baeldung.urlconnection;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+public class PostJSONWithHttpURLConnection {
+	
+	public static void main (String []args) throws IOException{
+		//Change the URL with any other publicly accessible POST resource, which accepts JSON request body
+		URL url = new URL ("https://reqres.in/api/users");
+		
+		HttpURLConnection con = (HttpURLConnection)url.openConnection();
+		con.setRequestMethod("POST");
+		
+		con.setRequestProperty("Content-Type", "application/json; utf-8");
+		con.setRequestProperty("Accept", "application/json");
+		
+		con.setDoOutput(true);
+		
+		//JSON String need to be constructed for the specific resource. 
+		//We may construct complex JSON using any third-party JSON libraries such as jackson or org.json
+		String jsonInputString = "{\"name\": \"Upendra\", \"job\": \"Programmer\"}";
+		
+		try(OutputStream os = con.getOutputStream()){
+			byte[] input = jsonInputString.getBytes("utf-8");
+			os.write(input, 0, input.length);			
+		}
+
+		int code = con.getResponseCode();
+		System.out.println(code);
+		
+		try(BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream(), "utf-8"))){
+			StringBuilder response = new StringBuilder();
+			String responseLine = null;
+			while ((responseLine = br.readLine()) != null) {
+				response.append(responseLine.trim());
+			}
+			System.out.println(response.toString());
+		}
+	}
+
+}

core-kotlin-2/README.md

@@ -1,3 +1,4 @@
 ## Relevant articles:
 
 - [Void Type in Kotlin](https://www.baeldung.com/kotlin-void-type)
+- [How to use Kotlin Range Expressions](https://www.baeldung.com/kotlin-ranges)

core-kotlin-2/src/test/kotlin/stringcomparison/StringComparisonTest.kt

@@ -0,0 +1,47 @@
+package stringcomparison
+
+import org.junit.Test
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class StringComparisonUnitTest {
+
+    @Test
+    fun `compare using equals operator`() {
+        val first = "kotlin"
+        val second = "kotlin"
+        val firstCapitalized = "KOTLIN"
+        assertTrue { first == second }
+        assertFalse { first == firstCapitalized }
+    }
+
+    @Test
+    fun `compare using referential equals operator`() {
+        val first = "kotlin"
+        val second = "kotlin"
+        val copyOfFirst = buildString { "kotlin" }
+        assertTrue { first === second }
+        assertFalse { first === copyOfFirst }
+    }
+
+    @Test
+    fun `compare using equals method`() {
+        val first = "kotlin"
+        val second = "kotlin"
+        val firstCapitalized = "KOTLIN"
+        assertTrue { first.equals(second) }
+        assertFalse { first.equals(firstCapitalized) }
+        assertTrue { first.equals(firstCapitalized, true) }
+    }
+
+    @Test
+    fun `compare using compare method`() {
+        val first = "kotlin"
+        val second = "kotlin"
+        val firstCapitalized = "KOTLIN"
+        assertTrue { first.compareTo(second) == 0 }
+        assertTrue { first.compareTo(firstCapitalized) == 32 }
+        assertTrue { firstCapitalized.compareTo(first) == -32 }
+        assertTrue { first.compareTo(firstCapitalized, true) == 0 }
+    }
+}

core-kotlin/README.md

@@ -52,3 +52,5 @@
 - [Inline Classes in Kotlin](https://www.baeldung.com/kotlin-inline-classes)
 - [Creating Java static final Equivalents in Kotlin](https://www.baeldung.com/kotlin-java-static-final)
 - [Nested forEach in Kotlin](https://www.baeldung.com/kotlin-nested-foreach)
+- [Building DSLs in Kotlin](https://www.baeldung.com/kotlin-dsl)
+- [Static Methods Behavior in Kotlin](https://www.baeldung.com/kotlin-static-methods)

geotools/pom.xml

@@ -33,24 +33,11 @@
 	</dependencies>
 
 	<repositories>
-		<repository>
-			<id>maven2-repository.dev.java.net</id>
-			<name>Java.net repository</name>
-			<url>http://download.java.net/maven/2</url>
-		</repository>
 		<repository>
 			<id>osgeo</id>
 			<name>Open Source Geospatial Foundation Repository</name>
 			<url>http://download.osgeo.org/webdav/geotools/</url>
 		</repository>
-		<repository>
-			<snapshots>
-				<enabled>true</enabled>
-			</snapshots>
-			<id>opengeo</id>
-			<name>OpenGeo Maven Repository</name>
-			<url>http://repo.opengeo.org</url>
-		</repository>
 	</repositories>
 
 	<properties>

gson/README.md

@@ -10,3 +10,4 @@
 - [Save Data to a JSON File with Gson](https://www.baeldung.com/gson-save-file)
 - [Convert JSON to a Map Using Gson](https://www.baeldung.com/gson-json-to-map)
 - [Working with Primitive Values in Gson](https://www.baeldung.com/java-gson-primitives)
+- [Convert String to JsonObject with Gson](https://www.baeldung.com/gson-string-to-jsonobject)

guice/README.md

@@ -2,3 +2,4 @@
 
 ### Relevant Articles
 - [Guide to Google Guice](http://www.baeldung.com/guice)
+- [Guice vs Spring – Dependency Injection](https://www.baeldung.com/guice-spring-dependency-injection)

java-collections-maps/README.md

@@ -20,3 +20,4 @@
 - [Comparing Two HashMaps in Java](https://www.baeldung.com/java-compare-hashmaps)
 - [Immutable Map Implementations in Java](https://www.baeldung.com/java-immutable-maps) 
 - [Map to String Conversion in Java](https://www.baeldung.com/java-map-to-string-conversion)
+- [Guide to Apache Commons MultiValuedMap](https://www.baeldung.com/apache-commons-multi-valued-map)

java-streams/src/main/java/com/baeldung/reduce/application/Application.java

@@ -0,0 +1,70 @@
+package com.baeldung.reduce.application;
+
+import com.baeldung.reduce.entities.User;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.Warmup;
+
+public class Application {
+
+    public static void main(String[] args) throws Exception {
+        List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
+        int result1 = numbers.stream().reduce(0, (subtotal, element) -> subtotal + element);
+        System.out.println(result1);
+
+        int result2 = numbers.stream().reduce(0, Integer::sum);
+        System.out.println(result2);
+
+        List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
+        String result3 = letters.stream().reduce("", (partialString, element) -> partialString + element);
+        System.out.println(result3);
+
+        String result4 = letters.stream().reduce("", String::concat);
+        System.out.println(result4);
+        
+        String result5 = letters.stream().reduce("", (partialString, element) -> partialString.toUpperCase() + element.toUpperCase());
+        System.out.println(result5);
+        
+        List<User> users = Arrays.asList(new User("John", 30), new User("Julie", 35));
+        int result6 = users.stream().reduce(0, (partialAgeResult, user) -> partialAgeResult + user.getAge(), Integer::sum);
+        System.out.println(result6);
+
+        String result7 = letters.parallelStream().reduce("", String::concat);
+        System.out.println(result7);
+
+        int result8 = users.parallelStream().reduce(0, (partialAgeResult, user) -> partialAgeResult + user.getAge(), Integer::sum);
+        System.out.println(result8);
+
+        org.openjdk.jmh.Main.main(args);
+        
+    }
+    
+    @Benchmark
+    @Fork(value = 1, warmups = 2)
+    @Warmup(iterations = 2) 
+    @BenchmarkMode(Mode.AverageTime)
+    public void executeReduceOnParallelizedStream() {
+        List<User> userList = new ArrayList<>();
+        for (int i = 0; i <= 1000000; i++) {
+            userList.add(new User("John" + i, i));
+        }
+        userList.parallelStream().reduce(0, (partialAgeResult, user) -> partialAgeResult + user.getAge(), Integer::sum);
+    }
+    
+    @Benchmark
+    @Fork(value = 1, warmups = 2)
+    @Warmup(iterations = 2) 
+    @BenchmarkMode(Mode.AverageTime)
+    public void executeReduceOnSequentialStream() {
+        List<User> userList = new ArrayList<>();
+        for (int i = 0; i <= 1000000; i++) {
+            userList.add(new User("John" + i, i));
+        }
+        userList.stream().reduce(0, (partialAgeResult, user) -> partialAgeResult + user.getAge(), Integer::sum);
+    }
+}

java-streams/src/main/java/com/baeldung/reduce/entities/User.java

@@ -0,0 +1,25 @@
+package com.baeldung.reduce.entities;
+
+public class User {
+
+    private final String name;
+    private final int age;
+
+    public User(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+    
+    @Override
+    public String toString() {
+        return "User{" + "name=" + name + ", age=" + age + '}';
+    }
+}

java-streams/src/main/java/com/baeldung/reduce/utilities/NumberUtils.java

@@ -0,0 +1,52 @@
+package com.baeldung.reduce.utilities;
+
+import java.util.List;
+import java.util.function.BiFunction;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public abstract class NumberUtils {
+
+    private static final Logger LOGGER = Logger.getLogger(NumberUtils.class.getName());
+
+    public static int divideListElements(List<Integer> values, Integer divider) {
+        return values.stream()
+                .reduce(0, (a, b) -> {
+                    try {
+                        return a / divider + b / divider;
+                    } catch (ArithmeticException e) {
+                        LOGGER.log(Level.INFO, "Arithmetic Exception: Division by Zero");
+                    }
+                    return 0;
+                });
+    }
+    
+    public static int divideListElementsWithExtractedTryCatchBlock(List<Integer> values, int divider) {
+        return values.stream().reduce(0, (a, b) -> divide(a, divider) + divide(b, divider));
+    }
+    
+    public static int divideListElementsWithApplyFunctionMethod(List<Integer> values, int divider) {
+        BiFunction<Integer, Integer, Integer> division = (a, b) -> a / b;
+        return values.stream().reduce(0, (a, b) -> applyFunction(division, a, divider) + applyFunction(division, b, divider));
+    }
+    
+    private static int divide(int value, int factor) {
+        int result = 0;
+        try {
+            result = value / factor;
+        } catch (ArithmeticException e) {
+            LOGGER.log(Level.INFO, "Arithmetic Exception: Division by Zero");
+        }
+        return result;
+    }
+    
+    private static int applyFunction(BiFunction<Integer, Integer, Integer> function, int a, int b) {
+        try {
+            return function.apply(a, b);
+        }
+        catch(Exception e) {
+            LOGGER.log(Level.INFO, "Exception occurred!");
+        }
+        return 0;
+    }
+}

java-streams/src/test/java/com/baeldung/reduce/tests/StreamReduceUnitTest.java

@@ -0,0 +1,79 @@
+package com.baeldung.reduce.tests;
+
+import com.baeldung.reduce.entities.User;
+import com.baeldung.reduce.utilities.NumberUtils;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.Test;
+
+public class StreamReduceUnitTest {
+
+    @Test
+    public void givenIntegerList_whenReduceWithSumAccumulatorLambda_thenCorrect() {
+        List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
+        int result = numbers.stream().reduce(0, (a, b) -> a + b);
+        assertThat(result).isEqualTo(21);
+    }
+
+    @Test
+    public void givenIntegerList_whenReduceWithSumAccumulatorMethodReference_thenCorrect() {
+        List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
+        int result = numbers.stream().reduce(0, Integer::sum);
+        assertThat(result).isEqualTo(21);
+    }
+
+    @Test
+    public void givenStringList_whenReduceWithConcatenatorAccumulatorLambda_thenCorrect() {
+        List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
+        String result = letters.stream().reduce("", (a, b) -> a + b);
+        assertThat(result).isEqualTo("abcde");
+    }
+
+    @Test
+    public void givenStringList_whenReduceWithConcatenatorAccumulatorMethodReference_thenCorrect() {
+        List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
+        String result = letters.stream().reduce("", String::concat);
+        assertThat(result).isEqualTo("abcde");
+    }
+
+    @Test
+    public void givenStringList_whenReduceWithUppercaseConcatenatorAccumulator_thenCorrect() {
+        List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
+        String result = letters.stream().reduce("", (a, b) -> a.toUpperCase() + b.toUpperCase());
+        assertThat(result).isEqualTo("ABCDE");
+    }
+
+    @Test
+    public void givenUserList_whenReduceWithAgeAccumulatorAndSumCombiner_thenCorrect() {
+        List<User> users = Arrays.asList(new User("John", 30), new User("Julie", 35));
+        int result = users.stream().reduce(0, (partialAgeResult, user) -> partialAgeResult + user.getAge(), Integer::sum);
+        assertThat(result).isEqualTo(65);
+    }
+
+    @Test
+    public void givenStringList_whenReduceWithParallelStream_thenCorrect() {
+        List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
+        String result = letters.parallelStream().reduce("", String::concat);
+        assertThat(result).isEqualTo("abcde");
+    }
+
+    @Test
+    public void givenNumberUtilsClass_whenCalledDivideListElements_thenCorrect() {
+        List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
+        assertThat(NumberUtils.divideListElements(numbers, 1)).isEqualTo(21);
+    }
+
+    @Test
+    public void givenNumberUtilsClass_whenCalledDivideListElementsWithExtractedTryCatchBlock_thenCorrect() {
+        List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
+        assertThat(NumberUtils.divideListElementsWithExtractedTryCatchBlock(numbers, 1)).isEqualTo(21);
+    }
+
+    @Test
+    public void givenStream_whneCalleddivideListElementsWithApplyFunctionMethod_thenCorrect() {
+        List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
+        assertThat(NumberUtils.divideListElementsWithApplyFunctionMethod(numbers, 1)).isEqualTo(21);
+    }
+}

java-strings/README.md

@@ -53,3 +53,4 @@
 - [Java String Interview Questions and Answers](https://www.baeldung.com/java-string-interview-questions)
 - [Check if a String is a Pangram in Java](https://www.baeldung.com/java-string-pangram)
 - [Check If a String Contains Multiple Keywords](https://www.baeldung.com/string-contains-multiple-words)
+- [Common String Operations in Java](https://www.baeldung.com/java-string-operations)

jhipster/README.md

@@ -3,3 +3,4 @@
 - [JHipster with a Microservice Architecture](http://www.baeldung.com/jhipster-microservices)
 - [Intro to JHipster](http://www.baeldung.com/jhipster)
 - [Building a Basic UAA-Secured JHipster Microservice](https://www.baeldung.com/jhipster-uaa-secured-micro-service)
+- [Creating New Roles and Authorities in JHipster](https://www.baeldung.com/jhipster-new-roles)

jhipster/jhipster-uaa/pom.xml

@@ -2,9 +2,8 @@
 <project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
     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.jhipster</groupId>
-    <artifactId>jhipster-microservice-uaa</artifactId>
-    <name>JHipster Microservice with UAA</name>
+    <artifactId>jhipster-uaa</artifactId>
+    <name>jhipster-uaa</name>
     <packaging>pom</packaging>
 
 	<parent>

json/README.md

@@ -11,3 +11,5 @@
 - [Overview of JSON Pointer](https://www.baeldung.com/json-pointer)
 - [Introduction to the JSON Binding API (JSR 367) in Java](http://www.baeldung.com/java-json-binding-api)
 - [Get a Value by Key in a JSONArray](https://www.baeldung.com/java-jsonarray-get-value-by-key)
+- [Iterating Over an Instance of org.json.JSONObject](https://www.baeldung.com/jsonobject-iteration)
+- [Testing Web APIs with Postman Collections](https://www.baeldung.com/postman-testing-collections)

libraries/README.md

@@ -66,6 +66,7 @@
 - [Implementing a FTP-Client in Java](http://www.baeldung.com/java-ftp-client)
 - [Introduction to Functional Java](https://www.baeldung.com/java-functional-library)
 - [Intro to Derive4J](https://www.baeldung.com/derive4j)
+- [A Guide to the Reflections Library](https://www.baeldung.com/reflections-library)
 
 The libraries module contains examples related to small libraries that are relatively easy to use and does not require any separate module of its own.