Merge remote-tracking branch 'upstream/master'

2023-10-01 21:48:56 +02:00
parent c56bc04f95 ae29eca0f8
commit a493c570ad
429 changed files with 4132 additions and 625 deletions
@@ -5,3 +5,4 @@
 - [Collecting Stream Elements into a List in Java](https://www.baeldung.com/java-stream-to-list-collecting)
 - [New Features in Java 16](https://www.baeldung.com/java-16-new-features)
 - [Guide to Java 8 groupingBy Collector](https://www.baeldung.com/java-groupingby-collector)
+- [Value-Based Classes in Java](https://www.baeldung.com/java-value-based-classes)
@@ -1,2 +1,3 @@
 ## Relevant Articles
 - [Sequenced Collections in Java 21](https://www.baeldung.com/java-21-sequenced-collections)
+- [String Templates in Java 21](https://www.baeldung.com/java-21-string-templates)
@@ -12,23 +12,36 @@
        <version>0.0.1-SNAPSHOT</version>
    </parent>

-<!--    <build>-->
-<!--        <plugins>-->
-<!--            <plugin>-->
-<!--                <groupId>org.apache.maven.plugins</groupId>-->
-<!--                <artifactId>maven-compiler-plugin</artifactId>-->
-<!--                <configuration>-->
-<!--                    <source>{maven.compiler.source.version}</source>-->
-<!--                    <target>{maven.compiler.target.version}</target>-->
-<!--                </configuration>-->
-<!--            </plugin>-->
-<!--        </plugins>-->
-<!--    </build>-->
+    <properties>
+        <maven.compiler.source.version>21</maven.compiler.source.version>
+        <maven.compiler.target.version>21</maven.compiler.target.version>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>

-<!--    <properties>-->
-<!--        <maven.compiler.source.version>21</maven.compiler.source.version>-->
-<!--        <maven.compiler.target.version>21</maven.compiler.target.version>-->
-<!--        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>-->
-<!--    </properties>-->
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>21</source>
+                    <target>21</target>
+                    <!-- Needed due to a bug with JDK 21, described here: https://issues.apache.org/jira/browse/MCOMPILER-546?page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel&focusedCommentId=17767513 -->
+                    <debug>false</debug>
+                    <compilerArgs>
+                        <arg>--enable-preview</arg>
+                    </compilerArgs>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <argLine>--enable-preview</argLine>
+                </configuration>
+            </plugin>
+
+        </plugins>
+    </build>

 </project>
@@ -0,0 +1,37 @@
+package com.baeldung.stringtemplates;
+
+import java.text.MessageFormat;
+
+public class StringCompositionTechniques {
+    String composeUsingPlus(String feelsLike, String temperature, String unit) {
+        return "Today's weather is " + feelsLike + ", with a temperature of " + temperature + " degrees " + unit;
+    }
+
+    String composeUsingStringBuffer(String feelsLike, String temperature, String unit) {
+        return new StringBuffer().append("Today's weather is ")
+          .append(feelsLike)
+          .append(", with a temperature of ")
+          .append(temperature)
+          .append(" degrees ")
+          .append(unit)
+          .toString();
+    }
+
+    String composeUsingStringBuilder(String feelsLike, String temperature, String unit) {
+        return new StringBuilder().append("Today's weather is ")
+          .append(feelsLike)
+          .append(", with a temperature of ")
+          .append(temperature)
+          .append(" degrees ")
+          .append(unit)
+          .toString();
+    }
+
+    String composeUsingFormatters(String feelsLike, String temperature, String unit) {
+        return String.format("Today's weather is %s, with a temperature of %s degrees %s", feelsLike, temperature, unit);
+    }
+
+    String composeUsingMessageFormatter(String feelsLike, String temperature, String unit) {
+        return MessageFormat.format("Today''s weather is {0}, with a temperature of {1} degrees {2}", feelsLike, temperature, unit);
+    }
+}
@@ -0,0 +1,56 @@
+package com.baeldung.stringtemplates;
+
+import static java.lang.StringTemplate.RAW;
+import static java.util.FormatProcessor.FMT;
+
+public class StringTemplateExamples {
+    String interpolationUsingSTRProcessor(String feelsLike, String temperature, String unit) {
+        return STR
+          . "Today's weather is \{ feelsLike }, with a temperature of \{ temperature } degrees \{ unit }" ;
+    }
+
+    String interpolationOfJSONBlock(String feelsLike, String temperature, String unit) {
+        return STR
+          . """
+          {
+            "feelsLike": "\{ feelsLike }",
+            "temperature": "\{ temperature }",
+            "unit": "\{ unit }"
+          }
+          """ ;
+    }
+
+    String interpolationWithExpressions() {
+        return STR
+          . "Today's weather is \{ getFeelsLike() }, with a temperature of \{ getTemperature() } degrees \{ getUnit() }" ;
+    }
+
+    String interpolationWithTemplates() {
+        StringTemplate str = RAW
+          . "Today's weather is \{ getFeelsLike() }, with a temperature of \{ getTemperature() } degrees \{ getUnit() }" ;
+        return STR.process(str);
+    }
+
+    String interpolationOfJSONBlockWithFMT(String feelsLike, float temperature, String unit) {
+        return FMT
+          . """
+      {
+        "feelsLike": "%1s\{ feelsLike }",
+        "temperature": "%2.2f\{ temperature }",
+        "unit": "%1s\{ unit }"
+      }
+      """ ;
+    }
+
+    private String getFeelsLike() {
+        return "pleasant";
+    }
+
+    private String getTemperature() {
+        return "25";
+    }
+
+    private String getUnit() {
+        return "Celsius";
+    }
+}
@@ -0,0 +1,11 @@
+package com.baeldung.unnamed.variables;
+
+public record Car<T extends Engine>(String name, String color, T engine) { }
+
+abstract class Engine { }
+
+class GasEngine extends Engine { }
+
+class ElectricEngine extends Engine { }
+
+class HybridEngine extends Engine { }
@@ -0,0 +1,50 @@
+package com.baeldung.unnamed.variables;
+
+public class UnnamedPatterns {
+
+    static String getObjectsColorWithNamedPattern(Object object) {
+        if (object instanceof Car(String name, String color, Engine engine)) {
+            return color;
+        }
+        return "No color!";
+    }
+
+    static String getObjectsColorWithUnnamedPattern(Object object) {
+        if (object instanceof Car(_, String color, _)) {
+            return color;
+        }
+        return "No color!";
+    }
+
+    static String getObjectsColorWithSwitchAndNamedPattern(Object object) {
+        return switch (object) {
+            case Car(String name, String color, Engine engine) -> color;
+            default -> "No color!";
+        };
+    }
+
+    static String getObjectsColorWithSwitchAndUnnamedPattern(Object object) {
+        return switch (object) {
+            case Car(_, String color, _) -> color;
+            default -> "No color!";
+        };
+    }
+
+    static String getEngineTypeWithNamedPattern(Car<?> car) {
+        return switch (car) {
+            case Car(String name, String color, GasEngine engine) -> "gas";
+            case Car(String name, String color, ElectricEngine engine) -> "electric";
+            case Car(String name, String color, HybridEngine engine) -> "hybrid";
+            default -> "none";
+        };
+    }
+
+    static String getEngineTypeWithUnnamedPattern(Car<?> car) {
+        return switch (car) {
+            case Car(_, _, GasEngine _) -> "gas";
+            case Car(_, _, ElectricEngine _) -> "electric";
+            case Car(_, _, HybridEngine _) -> "hybrid";
+            default -> "none";
+        };
+    }
+}
@@ -0,0 +1,134 @@
+package com.baeldung.unnamed.variables;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Queue;
+
+class Transaction implements AutoCloseable {
+
+    @Override
+    public void close() {
+        System.out.println("Closed!");
+    }
+}
+
+public class UnnamedVariables {
+
+    static int countCarsOverLimitWithNamedVariable(Collection<Car<?>> cars, int limit) {
+        var total = 0;
+        var totalOverLimit = 0;
+        for (var car : cars) {
+            total++;
+            if (total > limit) {
+                totalOverLimit++;
+                // side effect
+            }
+        }
+        return totalOverLimit;
+    }
+
+    static int countCarsOverLimitWithUnnamedVariable(Collection<Car<?>> cars, int limit) {
+        var total = 0;
+        var totalOverLimit = 0;
+        for (var _ : cars) {
+            total++;
+            if (total > limit) {
+                totalOverLimit++;
+                // side effect
+            }
+        }
+        return totalOverLimit;
+    }
+
+    static void sendNotificationToCarsWithNamedVariable(Collection<Car<?>> cars) {
+        sendOneTimeNotification();
+        for (int i = 0; i < cars.size(); i++) {
+            // Notify car
+        }
+    }
+
+    static void sendNotificationToCarsWithUnnamedVariable(Collection<Car<?>> cars) {
+        for (int i = 0, _ = sendOneTimeNotification(); i < cars.size(); i++) {
+            // Notify car
+        }
+    }
+
+    private static int sendOneTimeNotification() {
+        System.out.println("Sending one time notification!");
+        return 1;
+    }
+
+    static Car<?> removeThreeCarsAndReturnFirstRemovedWithNamedVariables(Queue<Car<?>> cars) {
+        var x = cars.poll();
+        var y = cars.poll();
+        var z = cars.poll();
+        return x;
+    }
+
+    static Car<?> removeThreeCarsAndReturnFirstRemovedWithUnnamedVariables(Queue<Car<?>> cars) {
+        var car = cars.poll();
+        var _ = cars.poll();
+        var _ = cars.poll();
+        return car;
+    }
+
+    static void handleCarExceptionWithNamedVariables(Car<?> car) {
+        try {
+            someOperationThatFails(car);
+        } catch (IllegalStateException ex) {
+            System.out.println("Got an illegal state exception for: " + car.name());
+        } catch (RuntimeException ex) {
+            System.out.println("Got a runtime exception!");
+        }
+    }
+
+    static void handleCarExceptionWithUnnamedVariables(Car<?> car) {
+        try {
+            someOperationThatFails(car);
+        } catch (IllegalStateException | NumberFormatException _) {
+            System.out.println("Got an illegal state exception for: " + car.name());
+        } catch (RuntimeException _) {
+            System.out.println("Got a runtime exception!");
+        }
+    }
+
+    static void obtainTransactionAndUpdateCarWithNamedVariables(Car<?> car) {
+        try (var transaction = new Transaction()) {
+            updateCar(car);
+        }
+    }
+
+    static void obtainTransactionAndUpdateCarWithUnnamedVariables(Car<?> car) {
+        try (var _ = new Transaction()) {
+            updateCar(car);
+        }
+    }
+
+    static void updateCar(Car<?> car) {
+        // Some update logic
+        System.out.println("Car updated!");
+    }
+
+    static Map<String, List<Car<?>>> getCarsByFirstLetterWithNamedVariables(List<Car<?>> cars) {
+        Map<String, List<Car<?>>> carMap = new HashMap<>();
+        cars.forEach(car ->
+            carMap.computeIfAbsent(car.name().substring(0, 1), firstLetter -> new ArrayList<>()).add(car)
+        );
+        return carMap;
+    }
+
+    static Map<String, List<Car<?>>> getCarsByFirstLetterWithUnnamedVariables(List<Car<?>> cars) {
+        Map<String, List<Car<?>>> carMap = new HashMap<>();
+        cars.forEach(car ->
+            carMap.computeIfAbsent(car.name().substring(0, 1), _ -> new ArrayList<>()).add(car)
+        );
+        return carMap;
+    }
+
+    private static void someOperationThatFails(Car<?> car) {
+        throw new IllegalStateException("Triggered exception for: " + car.name());
+    }
+}
@@ -0,0 +1,67 @@
+package com.baeldung.stringtemplates;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class StringTemplatesUnitTest {
+
+    @Test
+    public void whenStringConcat_thenReturnComposedString() {
+        StringCompositionTechniques stringCompositionTechniques = new StringCompositionTechniques();
+        Assert.assertEquals("Today's weather is pleasant, with a temperature of 25 degrees Celsius", stringCompositionTechniques.composeUsingPlus("pleasant", "25", "Celsius"));
+    }
+
+    @Test
+    public void whenStringBuffer_thenReturnComposedString() {
+        StringCompositionTechniques stringCompositionTechniques = new StringCompositionTechniques();
+        Assert.assertEquals("Today's weather is pleasant, with a temperature of 25 degrees Celsius", stringCompositionTechniques.composeUsingStringBuffer("pleasant", "25", "Celsius"));
+    }
+
+    @Test
+    public void whenStringBuilder_thenReturnComposedString() {
+        StringCompositionTechniques stringCompositionTechniques = new StringCompositionTechniques();
+        Assert.assertEquals("Today's weather is pleasant, with a temperature of 25 degrees Celsius", stringCompositionTechniques.composeUsingStringBuilder("pleasant", "25", "Celsius"));
+    }
+
+    @Test
+    public void whenStringFormatter_thenReturnComposedFormattedString() {
+        StringCompositionTechniques stringCompositionTechniques = new StringCompositionTechniques();
+        Assert.assertEquals("Today's weather is pleasant, with a temperature of 25 degrees Celsius", stringCompositionTechniques.composeUsingFormatters("pleasant", "25", "Celsius"));
+    }
+
+    @Test
+    public void whenMessageFormatter_thenReturnComposedFormattedString() {
+        StringCompositionTechniques stringCompositionTechniques = new StringCompositionTechniques();
+        Assert.assertEquals("Today's weather is pleasant, with a temperature of 25 degrees Celsius", stringCompositionTechniques.composeUsingMessageFormatter("pleasant", "25", "Celsius"));
+    }
+
+    @Test
+    public void whenUsingStringTemplateSTR_thenReturnInterpolatedString() {
+        StringTemplateExamples templateExamples = new StringTemplateExamples();
+        Assert.assertEquals("Today's weather is pleasant, with a temperature of 25 degrees Celsius", templateExamples.interpolationUsingSTRProcessor("pleasant", "25", "Celsius"));
+    }
+
+    @Test
+    public void whenUsingMultilineStringTemplateSTR_thenReturnInterpolatedString() {
+        StringTemplateExamples templateExamples = new StringTemplateExamples();
+        Assert.assertEquals("{\n" + "  \"feelsLike\": \"pleasant\",\n" + "  \"temperature\": \"25\",\n" + "  \"unit\": \"Celsius\"\n" + "}\n", templateExamples.interpolationOfJSONBlock("pleasant", "25", "Celsius"));
+    }
+
+    @Test
+    public void whenUsingExpressionSTR_thenReturnInterpolatedString() {
+        StringTemplateExamples templateExamples = new StringTemplateExamples();
+        Assert.assertEquals("Today's weather is pleasant, with a temperature of 25 degrees Celsius", templateExamples.interpolationWithExpressions());
+    }
+
+    @Test
+    public void whenUsingExpressionRAW_thenReturnInterpolatedString() {
+        StringTemplateExamples templateExamples = new StringTemplateExamples();
+        Assert.assertEquals("Today's weather is pleasant, with a temperature of 25 degrees Celsius", templateExamples.interpolationWithTemplates());
+    }
+
+    @Test
+    public void whenUsingExpressionFMT_thenReturnInterpolatedString() {
+        StringTemplateExamples templateExamples = new StringTemplateExamples();
+        Assert.assertEquals("{\n" + "  \"feelsLike\": \"pleasant\",\n" + "  \"temperature\": \"25.86\",\n" + "  \"unit\": \"Celsius\"\n" + "}\n", templateExamples.interpolationOfJSONBlockWithFMT("pleasant", 25.8636F, "Celsius"));
+    }
+}
@@ -0,0 +1,13 @@
+package com.baeldung.unnamed.variables;
+
+import java.util.List;
+
+class CarScenario {
+
+    protected final List<Car<?>> cars = List.of(
+        new Car<>("Mitsubishi", "blue", new GasEngine()),
+        new Car<>("Toyota", "red", new ElectricEngine()),
+        new Car<>("Jaguar", "white", new HybridEngine())
+    );
+
+}
@@ -0,0 +1,44 @@
+package com.baeldung.unnamed.variables;
+
+import static com.baeldung.unnamed.variables.UnnamedPatterns.getEngineTypeWithNamedPattern;
+import static com.baeldung.unnamed.variables.UnnamedPatterns.getEngineTypeWithUnnamedPattern;
+import static com.baeldung.unnamed.variables.UnnamedPatterns.getObjectsColorWithNamedPattern;
+import static com.baeldung.unnamed.variables.UnnamedPatterns.getObjectsColorWithSwitchAndNamedPattern;
+import static com.baeldung.unnamed.variables.UnnamedPatterns.getObjectsColorWithSwitchAndUnnamedPattern;
+import static com.baeldung.unnamed.variables.UnnamedPatterns.getObjectsColorWithUnnamedPattern;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class UnnamedPatternsUnitTest extends CarScenario {
+
+    @Test
+    public void whenExtractingColorWithNamedPatterns_thenReturnBlue() {
+        assertEquals("blue", getObjectsColorWithNamedPattern(cars.get(0)));
+    }
+
+    @Test
+    public void whenExtractingColorWithUnnamedPatterns_thenReturnBlue() {
+        assertEquals("blue", getObjectsColorWithUnnamedPattern(cars.get(0)));
+    }
+
+    @Test
+    public void whenExtractingColorWithSwitchAndNamedPatterns_thenReturnBlue() {
+        assertEquals("blue", getObjectsColorWithSwitchAndNamedPattern(cars.get(0)));
+    }
+
+    @Test
+    public void whenExtractingColorWithSwitchAndUnnamedPatterns_thenReturnBlue() {
+        assertEquals("blue", getObjectsColorWithSwitchAndUnnamedPattern(cars.get(0)));
+    }
+
+    @Test
+    public void whenExtractingEngineTypeWithNamedPatterns_thenReturnGas() {
+        assertEquals("gas", getEngineTypeWithNamedPattern(cars.get(0)));
+    }
+
+    @Test
+    public void whenExtractingEngineTypeWithUnnamedPatterns_thenReturnGas() {
+        assertEquals("gas", getEngineTypeWithUnnamedPattern(cars.get(0)));
+    }
+}
@@ -0,0 +1,93 @@
+package com.baeldung.unnamed.variables;
+
+import static com.baeldung.unnamed.variables.UnnamedVariables.countCarsOverLimitWithNamedVariable;
+import static com.baeldung.unnamed.variables.UnnamedVariables.countCarsOverLimitWithUnnamedVariable;
+import static com.baeldung.unnamed.variables.UnnamedVariables.getCarsByFirstLetterWithNamedVariables;
+import static com.baeldung.unnamed.variables.UnnamedVariables.getCarsByFirstLetterWithUnnamedVariables;
+import static com.baeldung.unnamed.variables.UnnamedVariables.handleCarExceptionWithNamedVariables;
+import static com.baeldung.unnamed.variables.UnnamedVariables.handleCarExceptionWithUnnamedVariables;
+import static com.baeldung.unnamed.variables.UnnamedVariables.obtainTransactionAndUpdateCarWithNamedVariables;
+import static com.baeldung.unnamed.variables.UnnamedVariables.obtainTransactionAndUpdateCarWithUnnamedVariables;
+import static com.baeldung.unnamed.variables.UnnamedVariables.removeThreeCarsAndReturnFirstRemovedWithNamedVariables;
+import static com.baeldung.unnamed.variables.UnnamedVariables.removeThreeCarsAndReturnFirstRemovedWithUnnamedVariables;
+import static com.baeldung.unnamed.variables.UnnamedVariables.sendNotificationToCarsWithNamedVariable;
+import static com.baeldung.unnamed.variables.UnnamedVariables.sendNotificationToCarsWithUnnamedVariable;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.LinkedList;
+
+import org.junit.jupiter.api.Test;
+
+public class UnnamedVariablesUnitTest extends CarScenario {
+
+    @Test
+    public void whenCountingCarsOverLimitWithNamedVariables_thenShouldReturnOne() {
+        assertEquals(1, countCarsOverLimitWithNamedVariable(cars, 2));
+    }
+
+    @Test
+    public void whenCountingCarsOverLimitWithUnnamedVariables_thenShouldReturnOne() {
+        assertEquals(1, countCarsOverLimitWithUnnamedVariable(cars, 2));
+    }
+
+    @Test
+    public void whenNotifyingCarsWithNamedVariables_thenShouldNotFail() {
+        assertDoesNotThrow(() -> sendNotificationToCarsWithNamedVariable(cars));
+    }
+
+    @Test
+    public void whenNotifyingCarsWithUnnamedVariables_thenShouldNotFail() {
+        assertDoesNotThrow(() -> sendNotificationToCarsWithUnnamedVariable(cars));
+    }
+
+    @Test
+    public void whenPollingCarsWithNamedVariables_thenReturnFirstOneAndEmptyQueue() {
+        var carQueue = new LinkedList<>(cars);
+        assertEquals("Mitsubishi", removeThreeCarsAndReturnFirstRemovedWithNamedVariables(carQueue).name());
+        assertEquals(0, carQueue.size());
+    }
+
+    @Test
+    public void whenPollingCarsWithUnnamedVariables_thenReturnFirstOneAndEmptyQueue() {
+        var carQueue = new LinkedList<>(cars);
+        assertEquals("Mitsubishi", removeThreeCarsAndReturnFirstRemovedWithUnnamedVariables(carQueue).name());
+        assertEquals(0, carQueue.size());
+    }
+
+    @Test
+    public void whenHandlingExceptionWithNamedVariables_thenNoExceptionIsThrown() {
+        assertDoesNotThrow(() -> handleCarExceptionWithNamedVariables(cars.get(0)));
+    }
+
+    @Test
+    public void whenHandlingExceptionWithUnnamedVariables_thenNoExceptionIsThrown() {
+        assertDoesNotThrow(() -> handleCarExceptionWithUnnamedVariables(cars.get(0)));
+    }
+
+    @Test
+    public void whenHandlingTransactionUpdateWithNamedVariables_thenNoExceptionIsThrown() {
+        assertDoesNotThrow(() -> obtainTransactionAndUpdateCarWithNamedVariables(cars.get(0)));
+    }
+
+    @Test
+    public void whenHandlingTransactionUpdateWithUnnamedVariables_thenNoExceptionIsThrown() {
+        assertDoesNotThrow(() -> obtainTransactionAndUpdateCarWithUnnamedVariables(cars.get(0)));
+    }
+
+    @Test
+    public void whenGettingCarsByFirstLetterWithNamedVariables_thenHaveThreeKeys() {
+        var carsByLetter = getCarsByFirstLetterWithNamedVariables(cars);
+        assertEquals(1, carsByLetter.get("M").size());
+        assertEquals(1, carsByLetter.get("T").size());
+        assertEquals(1, carsByLetter.get("J").size());
+    }
+
+    @Test
+    public void whenGettingCarsByFirstLetterWithUnnamedVariables_thenHaveThreeKeys() {
+        var carsByLetter = getCarsByFirstLetterWithUnnamedVariables(cars);
+        assertEquals(1, carsByLetter.get("M").size());
+        assertEquals(1, carsByLetter.get("T").size());
+        assertEquals(1, carsByLetter.get("J").size());
+    }
+}
@@ -4,3 +4,4 @@ This module contains articles about Java 9 streams

 ### Relevant Articles: 
 - [How to Break from Java Stream forEach](https://www.baeldung.com/java-break-stream-foreach)
+- [Creating Stream of Regex Matches](https://www.baeldung.com/java-stream-regex-matches)
@@ -9,3 +9,4 @@ This module contains complete guides about arrays in Java
 - [Guide to ArrayStoreException](https://www.baeldung.com/java-arraystoreexception)
 - [Creating a Generic Array in Java](https://www.baeldung.com/java-generic-array)
 - [Maximum Size of Java Arrays](https://www.baeldung.com/java-arrays-max-size)
+- [Merge Two Arrays and Remove Duplicates in Java](https://www.baeldung.com/java-merge-two-arrays-delete-duplicates)
@@ -0,0 +1,2 @@
+## Relevant Articles
+- [Find the Middle Element of an Array in Java](https://www.baeldung.com/java-array-middle-item)
@@ -14,4 +14,3 @@ This module contains articles about advanced operations on arrays in Java. They
 - [Slicing Arrays in Java](https://www.baeldung.com/java-slicing-arrays)
 - [Combining Two or More Byte Arrays](https://www.baeldung.com/java-concatenate-byte-arrays)
 - [Calculating the Sum of Two Arrays in Java](https://www.baeldung.com/java-sum-arrays-element-wise)
- [Find the Middle Element of an Array in Java](https://www.baeldung.com/java-array-middle-item)
@@ -0,0 +1,29 @@
+package com.baeldung.incrementchar;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+class IncrementCharUnitTest {
+    @Test
+    void whenUsingForLoop_thenGenerateCharacters(){
+        final List<Character> allCapitalCharacters = Arrays.asList('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z');
+        List<Character> characters = new ArrayList<>();
+        for (char character = 'A'; character <= 'Z'; character++) {
+            characters.add(character);
+        }
+        Assertions.assertEquals(characters, allCapitalCharacters);
+    }
+
+    @Test
+    void whenUsingStreams_thenGenerateCharacters() {
+        final List<Character> allCapitalCharacters = Arrays.asList('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z');
+        final List<Character> characters = IntStream.rangeClosed('A', 'Z').mapToObj(c -> (char) c).collect(Collectors.toList());
+        Assertions.assertEquals(characters, allCapitalCharacters);
+    }
+}
@@ -0,0 +1,126 @@
+package com.baeldung.skippingfirstelement;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+public class SkipFirstElementExample {
+
+    private final List<String> stringList = new ArrayList<>();
+    private final Set<String> stringSet = new HashSet<>();
+    private final Map<String, String> stringMap = new HashMap<>();
+
+    public SkipFirstElementExample() {
+        // Initializing a List
+        stringList.add("Monday");
+        stringList.add("Tuesday");
+        stringList.add("Wednesday");
+        stringList.add("Thursday");
+        stringList.add("Friday");
+        stringList.add("Saturday");
+        stringList.add("Sunday");
+        // Initializing a Set
+        stringSet.add("Monday");
+        stringSet.add("Tuesday");
+        stringSet.add("Wednesday");
+        stringSet.add("Thursday");
+        stringSet.add("Friday");
+        stringSet.add("Saturday");
+        stringSet.add("Sunday");
+        // Initializing a Map
+        stringMap.put("Monday", "The day when coffee is a life support system.");
+        stringMap.put("Tuesday", "The day you realize that Monday's optimism was a lie.");
+        stringMap.put("Wednesday", "Hump Day, or as it's known, the 'Is it Friday yet?' day.");
+        stringMap.put("Thursday", "The day that says, 'Hold my beer, Friday is coming!'");
+        stringMap.put("Friday", "The golden child of the weekdays. The superhero of the workweek.");
+        stringMap.put("Saturday", "The day of rest? More like the day of 'What can I binge-watch next?'");
+        stringMap.put("Sunday", "The day before you have to adult again.");
+    }
+
+    void skippingFirstElementInListWithForLoop(List<String> stringList) {
+        for (int i = 1; i < stringList.size(); i++) {
+            process(stringList.get(i));
+        }
+    }
+
+    void skippingFirstElementInListWithWhileLoop(List<String> stringList) {
+        final Iterator<String> iterator = stringList.iterator();
+        if (iterator.hasNext()) {
+            iterator.next();
+        }
+        while (iterator.hasNext()) {
+            process(iterator.next());
+        }
+    }
+
+    void skippingFirstElementInSetWithWhileLoop(Set<String> stringSet) {
+        final Iterator<String> iterator = stringSet.iterator();
+        if (iterator.hasNext()) {
+            iterator.next();
+        }
+        while (iterator.hasNext()) {
+            process(iterator.next());
+        }
+    }
+
+    void skippingFirstElementInListWithWhileLoopStoringFirstElement(List<String> stringList) {
+        final Iterator<String> iterator = stringList.iterator();
+        String firstElement = null;
+        if (iterator.hasNext()) {
+            firstElement = iterator.next();
+        }
+        while (iterator.hasNext()) {
+            process(iterator.next());
+            // additional logic using fistElement
+        }
+    }
+
+    void skippingFirstElementInMapWithStreamSkip(Map<String, String> stringMap) {
+        stringMap.entrySet().stream().skip(1).forEach(this::process);
+    }
+
+    void skippingFirstElementInListWithSubList(List<String> stringList) {
+        for (final String element : stringList.subList(1, stringList.size())) {
+            process(element);
+        }
+    }
+
+    void skippingFirstElementInListWithForLoopWithAdditionalCheck(List<String> stringList) {
+        for (int i = 0; i < stringList.size(); i++) {
+            if (i == 0) {
+                // do something else
+            } else {
+                process(stringList.get(i));
+            }
+        }
+    }
+
+    void skippingFirstElementInListWithWhileLoopWithCounter(List<String> stringList) {
+        int counter = 0;
+        while (counter < stringList.size()) {
+            if (counter != 0) {
+                process(stringList.get(counter));
+            }
+            ++counter;
+        }
+    }
+
+    void skippingFirstElementInListWithReduce(List<String> stringList) {
+        stringList.stream().reduce((skip, element) -> {
+            process(element);
+            return element;
+        });
+    }
+
+    protected void process(String string) {
+        System.out.println(string);
+    }
+    protected void process(Entry<String, String> mapEntry) {
+        System.out.println(mapEntry);
+    }
+}
@@ -0,0 +1,122 @@
+package com.baeldung.skippingfirstelement;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.condition.EnabledForJreRange;
+import org.junit.jupiter.api.condition.JRE;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+@EnabledForJreRange(min = JRE.JAVA_9)
+class SkipFirstElementExampleUnitTest {
+
+    private static TestableSkipFirstElement testableSkip = new TestableSkipFirstElement();
+
+    @BeforeEach
+    void setup() {
+        testableSkip.reset();
+    }
+
+    private static Stream<Arguments> listProvider() {
+        return Stream.of(
+            Arguments.of(
+                List.of("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"),
+                List.of("Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"))
+        );
+    }
+
+    private static Stream<Arguments> mapProvider() {
+        return Stream.of(
+            Arguments.of(
+                Map.of(
+                    "Monday", "The day when coffee is a life support system.",
+                    "Tuesday", "The day you realize that Monday's optimism was a lie.",
+                    "Wednesday", "Hump Day, or as it's known, the 'Is it Friday yet?' day.",
+                    "Thursday", "The day that says, 'Hold my beer, Friday is coming!'",
+                    "Friday", "The golden child of the weekdays. The superhero of the workweek.",
+                    "Saturday", "The day of rest? More like the day of 'What can I binge-watch next?'",
+                    "Sunday", "The day before you have to adult again."
+                )
+            )
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("listProvider")
+    void skippingFirstElementInListWithForLoop(List<String> input, List<String> expected) {
+        testableSkip.skippingFirstElementInListWithForLoop(input);
+        List<?> actual = testableSkip.getResult();
+        assertEquals(actual, expected);
+    }
+
+    @ParameterizedTest
+    @MethodSource("listProvider")
+    void skippingFirstElementInListWithWhileLoop(List<String> input, List<String> expected) {
+        testableSkip.skippingFirstElementInListWithWhileLoop(input);
+        List<?> actual = testableSkip.getResult();
+        assertEquals(actual, expected);
+    }
+
+    @ParameterizedTest
+    @MethodSource("listProvider")
+    void skippingFirstElementInSetWithWhileLoop(List<String> input) {
+        testableSkip.skippingFirstElementInSetWithWhileLoop(new HashSet<>(input));
+        Set<?> actual = new HashSet<>(testableSkip.getResult());
+        assertEquals(actual.size(), input.size() - 1);
+    }
+
+    @ParameterizedTest
+    @MethodSource("listProvider")
+    void skippingFirstElementInListWithWhileLoopStoringFirstElement(List<String> input, List<String> expected) {
+        testableSkip.skippingFirstElementInListWithWhileLoopStoringFirstElement(input);
+        List<?> actual = testableSkip.getResult();
+        assertEquals(actual, expected);
+    }
+
+    @ParameterizedTest
+    @MethodSource("mapProvider")
+    void skippingFirstElementInMapWithStreamSkip(Map<String, String> input) {
+        testableSkip.skippingFirstElementInMapWithStreamSkip(input);
+        List<?> actual = testableSkip.getResult();
+        assertEquals(actual.size(), input.size() - 1);
+    }
+
+    @ParameterizedTest
+    @MethodSource("listProvider")
+    void skippingFirstElementInListWithSubList(List<String> input, List<String> expected) {
+        testableSkip.skippingFirstElementInListWithSubList(input);
+        List<?> actual = testableSkip.getResult();
+        assertEquals(actual, expected);
+    }
+
+    @ParameterizedTest
+    @MethodSource("listProvider")
+    void skippingFirstElementInListWithForLoopWithAdditionalCheck(List<String> input, List<String> expected) {
+        testableSkip.skippingFirstElementInListWithForLoopWithAdditionalCheck(input);
+        List<?> actual = testableSkip.getResult();
+        assertEquals(actual, expected);
+    }
+
+    @ParameterizedTest
+    @MethodSource("listProvider")
+    void skippingFirstElementInListWithWhileLoopWithCounter(List<String> input, List<String> expected) {
+        testableSkip.skippingFirstElementInListWithWhileLoopWithCounter(input);
+        List<?> actual = testableSkip.getResult();
+        assertEquals(actual, expected);
+    }
+
+    @ParameterizedTest
+    @MethodSource("listProvider")
+    void skippingFirstElementInListWithReduce(List<String> input, List<String> expected) {
+        testableSkip.skippingFirstElementInListWithReduce(input);
+        List<?> actual = testableSkip.getResult();
+        assertEquals(actual, expected);
+    }
+}
@@ -0,0 +1,10 @@
+package com.baeldung.skippingfirstelement;
+
+import java.util.List;
+
+public interface TestableSkip {
+
+    void reset();
+
+    List<?> getResult();
+}
@@ -0,0 +1,37 @@
+package com.baeldung.skippingfirstelement;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map.Entry;
+
+public class TestableSkipFirstElement extends SkipFirstElementExample implements TestableSkip {
+
+
+    private List<String> processedList = new ArrayList<>();
+    private List<Entry<String, String>> processedEntryList = new ArrayList<>();
+
+    @Override
+    public void process(String string) {
+        processedList.add(string);
+    }
+
+    @Override
+    public void process(Entry<String, String> stringEntry) {
+        processedEntryList.add(stringEntry);
+    }
+
+    @Override
+    public void reset() {
+        processedList.clear();
+        processedEntryList.clear();
+    }
+
+    @Override
+    public List<?> getResult() {
+        if (!processedList.isEmpty())
+            return processedList;
+        return processedEntryList;
+    }
+
+
+}
@@ -0,0 +1,5 @@
+## Java Collections Cookbooks and Examples
+
+This module contains articles about conversions among Collection types in Java.
+
+### Relevant Articles:
@@ -0,0 +1,26 @@
+<?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>core-java-collections-conversions-3</artifactId>
+    <name>core-java-collections-conversions-3</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+
+    <build>
+        <finalName>core-java-collections-conversions-3</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
+</project>
@@ -0,0 +1,66 @@
+package com.baeldung.hashmaptoarraylist;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Maps.EntryTransformer;
+
+public class HashMapToArrayListConverterUtils {
+
+    static ArrayList<String> convertUsingConstructor(HashMap<Integer, String> hashMap) {
+        if (hashMap == null) {
+            return null;
+        }
+        return new ArrayList<String>(hashMap.values());
+    }
+
+    static ArrayList<String> convertUsingAddAllMethod(HashMap<Integer, String> hashMap) {
+        if (hashMap == null) {
+            return null;
+        }
+
+        ArrayList<String> arrayList = new ArrayList<String>(hashMap.size());
+        arrayList.addAll(hashMap.values());
+
+        return arrayList;
+    }
+
+    static ArrayList<String> convertUsingStreamApi(HashMap<Integer, String> hashMap) {
+        if (hashMap == null) {
+            return null;
+        }
+
+        return hashMap.values()
+            .stream()
+            .collect(Collectors.toCollection(ArrayList::new));
+    }
+
+    static ArrayList<String> convertUsingForLoop(HashMap<Integer, String> hashMap) {
+        if (hashMap == null) {
+            return null;
+        }
+
+        ArrayList<String> arrayList = new ArrayList<String>(hashMap.size());
+        for (Map.Entry<Integer, String> entry : hashMap.entrySet()) {
+            arrayList.add(entry.getValue());
+        }
+
+        return arrayList;
+    }
+
+    static public ArrayList<String> convertUsingGuava(HashMap<Integer, String> hashMap) {
+        if (hashMap == null) {
+            return null;
+        }
+
+        EntryTransformer<Integer, String, String> entryMapTransformer = (key, value) -> value;
+
+        return Lists.newArrayList(Maps.transformEntries(hashMap, entryMapTransformer)
+            .values());
+    }
+
+}
@@ -0,0 +1,60 @@
+package com.baeldung.hashmaptoarraylist;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsInAnyOrder;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class HashMapToArrayListConverterUtilsUnitTest {
+
+    private HashMap<Integer, String> hashMap;
+
+    @Before
+    public void beforeEach() {
+        hashMap = new HashMap<>();
+        hashMap.put(1, "AAA");
+        hashMap.put(2, "BBB");
+        hashMap.put(3, "CCC");
+        hashMap.put(4, "DDD");
+    }
+
+    @Test
+    public void givenAHashMap_whenConvertUsingConstructor_thenReturnArrayList() {
+        ArrayList<String> myList = HashMapToArrayListConverterUtils.convertUsingConstructor(hashMap);
+
+        assertThat(hashMap.values(), containsInAnyOrder(myList.toArray()));
+    }
+
+    @Test
+    public void givenAHashMap_whenConvertUsingAddAllMethod_thenReturnArrayList() {
+        ArrayList<String> myList = HashMapToArrayListConverterUtils.convertUsingAddAllMethod(hashMap);
+
+        assertThat(hashMap.values(), containsInAnyOrder(myList.toArray()));
+    }
+
+    @Test
+    public void givenAHashMap_whenConvertUsingForLoop_thenReturnArrayList() {
+        ArrayList<String> myList = HashMapToArrayListConverterUtils.convertUsingForLoop(hashMap);
+
+        assertThat(hashMap.values(), containsInAnyOrder(myList.toArray()));
+    }
+
+    @Test
+    public void givenAHashMap_whenConvertUsingStreamApi_thenReturnArrayList() {
+        ArrayList<String> myList = HashMapToArrayListConverterUtils.convertUsingStreamApi(hashMap);
+
+        assertThat(hashMap.values(), containsInAnyOrder(myList.toArray()));
+    }
+
+    @Test
+    public void givenAHashMap_whenConvertUsingGuava_thenReturnArrayList() {
+        ArrayList<String> myList = HashMapToArrayListConverterUtils.convertUsingGuava(hashMap);
+
+        assertThat(hashMap.values(), containsInAnyOrder(myList.toArray()));
+    }
+
+}
@@ -0,0 +1,2 @@
+## Relevant Articles
+- [Check if a List Contains a String Element While Ignoring Case](https://www.baeldung.com/java-list-search-case-insensitive)
@@ -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>core-java-collections-list-6</artifactId>
+    <name>core-java-collections-list-6</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+</project>
@@ -0,0 +1,44 @@
+package com.baeldung.lists;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+public class StringListCaseInsensitiveContainsUnitTest {
+    private final static List<String> THE_LIST = List.of("Game of Thrones", "Forrest Gump", "American Beauty", "Pretty Woman", "Catch Me If You Can");
+
+    @Test
+    void whenUsingContains_thenGetExpectedResult() {
+        assertFalse(THE_LIST.contains("catch me if you can"));
+    }
+
+    boolean ignoreCaseContainsForLoop(List<String> list, String value) {
+        for (String e : list) {
+            if (value.equalsIgnoreCase(e))
+                return true;
+        }
+        return false;
+    }
+
+    @Test
+    void whenUsingIgnoreCaseContainsForLoop_thenGetExpectedResult() {
+        assertTrue(ignoreCaseContainsForLoop(THE_LIST, "CATCH me if you CAN"));
+        assertTrue(ignoreCaseContainsForLoop(THE_LIST, "game of thrones"));
+        assertFalse(ignoreCaseContainsForLoop(THE_LIST, "The Godfather"));
+    }
+
+    @Test
+    void whenUsingIgnoreCaseContainsStream_thenGetExpectedResult() {
+        assertTrue(THE_LIST.stream()
+          .anyMatch(e -> e.equalsIgnoreCase("CATCH me if you CAN")));
+
+        assertTrue(THE_LIST.stream()
+          .anyMatch("game of thrones"::equalsIgnoreCase));
+
+        assertFalse(THE_LIST.stream()
+          .anyMatch("The Godfather"::equalsIgnoreCase));
+    }
+}
@@ -1,76 +0,0 @@
-package java.com.baeldung.objecttomap;
-import com.google.gson.Gson;
-import org.junit.Assert;
-import org.junit.Test;
-import wiremock.com.fasterxml.jackson.core.type.TypeReference;
-import wiremock.com.fasterxml.jackson.databind.ObjectMapper;
-import wiremock.com.google.common.reflect.TypeToken;
-import java.lang.reflect.Field;
-import java.util.HashMap;
-import java.util.Map;
-
-public class ObjectToMapUnitTest {
-    Employee employee = new Employee("John", 3000.0);
-
-    @Test
-    public void givenJavaObject_whenUsingReflection_thenConvertToMap() throws IllegalAccessException {
-        Map<String, Object> map = convertUsingReflection(employee);
-        Assert.assertEquals(employee.getName(), map.get("name"));
-        Assert.assertEquals(employee.getSalary(), map.get("salary"));
-    }
-
-    private Map<String, Object> convertUsingReflection(Object object) throws IllegalAccessException {
-        Map<String, Object> map = new HashMap<>();
-        Field[] fields = object.getClass().getDeclaredFields();
-
-        for (Field field : fields) {
-            field.setAccessible(true);
-            map.put(field.getName(), field.get(object));
-        }
-
-        return map;
-    }
-
-    @Test
-    public void givenJavaObject_whenUsingJackson_thenConvertToMap() {
-        ObjectMapper objectMapper = new ObjectMapper();
-        Map<String, Object> map = objectMapper.convertValue(employee, new TypeReference<Map<String, Object>>() {});
-        Assert.assertEquals(employee.getName(), map.get("name"));
-        Assert.assertEquals(employee.getSalary(), map.get("salary"));
-    }
-
-    @Test
-    public void givenJavaObject_whenUsingGson_thenConvertToMap() {
-        Gson gson = new Gson();
-        String json = gson.toJson(employee);
-        Map<String, Object> map = gson.fromJson(json, new TypeToken<Map<String, Object>>() {}.getType());
-        Assert.assertEquals(employee.getName(), map.get("name"));
-        Assert.assertEquals(employee.getSalary(), map.get("salary"));
-    }
-
-    private static class Employee {
-        private String name;
-        private Double salary;
-
-        public Employee(String name, Double salary) {
-            this.name = name;
-            this.salary = salary;
-        }
-
-        public String getName() {
-            return name;
-        }
-
-        public void setName(String name) {
-            this.name = name;
-        }
-
-        public Double getSalary() {
-            return salary;
-        }
-
-        public void setSalary(Double age) {
-            this.salary = salary;
-        }
-    }
-}
@@ -0,0 +1,128 @@
+package com.baeldung.objecttomap;
+
+import static org.junit.Assert.assertEquals;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.common.reflect.TypeToken;
+import com.google.gson.Gson;
+import org.junit.Test;
+import java.lang.reflect.Field;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.SortedMap;
+import java.util.TreeMap;
+import java.util.stream.Collectors;
+
+public class ObjectToMapUnitTest {
+    Employee employee = new Employee("John", 3000.0);
+
+    @Test
+    public void givenJavaObject_whenUsingReflection_thenConvertToMap() throws IllegalAccessException {
+        Map<String, Object> map = convertUsingReflection(employee);
+        assertEquals(employee.getName(), map.get("name"));
+        assertEquals(employee.getSalary(), map.get("salary"));
+    }
+
+    private Map<String, Object> convertUsingReflection(Object object) throws IllegalAccessException {
+        Map<String, Object> map = new HashMap<>();
+        Field[] fields = object.getClass().getDeclaredFields();
+
+        for (Field field : fields) {
+            field.setAccessible(true);
+            map.put(field.getName(), field.get(object));
+        }
+
+        return map;
+    }
+
+    @Test
+    public void givenJavaObject_whenUsingJackson_thenConvertToMap() {
+        ObjectMapper objectMapper = new ObjectMapper();
+        Map<String, Object> map = objectMapper.convertValue(employee, new TypeReference<Map<String, Object>>() {});
+        assertEquals(employee.getName(), map.get("name"));
+        assertEquals(employee.getSalary(), map.get("salary"));
+    }
+
+    @Test
+    public void givenJavaObject_whenUsingGson_thenConvertToMap() {
+        Gson gson = new Gson();
+        String json = gson.toJson(employee);
+        Map<String, Object> map = gson.fromJson(json, new TypeToken<Map<String, Object>>() {}.getType());
+        assertEquals(employee.getName(), map.get("name"));
+        assertEquals(employee.getSalary(), map.get("salary"));
+    }
+
+    @Test
+    public void given_UnsortedMap_whenSortingByValueDescending_thenValuesAreInDescendingOrder() {
+        Map<String, Integer> unsortedMap = new HashMap<>();
+        unsortedMap.put("one", 1);
+        unsortedMap.put("three", 3);
+        unsortedMap.put("five", 5);
+        unsortedMap.put("two", 2);
+        unsortedMap.put("four", 4);
+
+        Map<String, Integer> sortedMap = sortMapByValueDescending(unsortedMap);
+
+        assertEquals(5, sortedMap.size());
+        final Iterator<Integer> iterator = sortedMap.values().iterator();
+        assertEquals(5, (int) iterator.next());
+        assertEquals(4, (int) iterator.next());
+        assertEquals(3, (int) iterator.next());
+        assertEquals(2, (int) iterator.next());
+        assertEquals(1, (int) iterator.next());
+    }
+
+    @Test
+    public void given_UnsortedMap_whenUsingTreeMap_thenKeysAreInDescendingOrder() {
+        SortedMap<String, Integer> treeMap = new TreeMap<>(Comparator.reverseOrder());
+        treeMap.put("one", 1);
+        treeMap.put("three", 3);
+        treeMap.put("five", 5);
+        treeMap.put("two", 2);
+        treeMap.put("four", 4);
+
+        assertEquals(5, treeMap.size());
+        final Iterator<String> iterator = treeMap.keySet().iterator();
+        assertEquals("two", iterator.next());
+        assertEquals("three", iterator.next());
+        assertEquals("one", iterator.next());
+        assertEquals("four", iterator.next());
+        assertEquals("five", iterator.next());
+    }
+
+    private static class Employee {
+        private String name;
+        private Double salary;
+
+        public Employee(String name, Double salary) {
+            this.name = name;
+            this.salary = salary;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public void setName(String name) {
+            this.name = name;
+        }
+
+        public Double getSalary() {
+            return salary;
+        }
+
+        public void setSalary(Double age) {
+            this.salary = salary;
+        }
+    }
+
+    public static <K, V extends Comparable<? super V>> Map<K, V> sortMapByValueDescending(Map<K, V> map) {
+        return map.entrySet().stream()
+                .sorted(Map.Entry.<K, V>comparingByValue().reversed())
+                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (e1, e2) -> e1, LinkedHashMap::new));
+    }
+}
--- a/Show More
+++ b/Show More