Merge branch 'master' into BAEL-3095

.gitignore

@@ -1,4 +1,5 @@
 */bin/*
+bin/
 
 *.class
 
@@ -21,6 +22,9 @@
 *.iws
 out/
 
+# VSCode
+.vscode/
+
 # Mac
 .DS_Store
 

README.md

@@ -1,12 +1,16 @@
 
-The "REST with Spring" Classes
+The Courses
 ==============================
 
-Here's the Master Class of REST With Spring (along with the newly announced Boot 2 material): <br/>
-**[>> THE REST WITH SPRING - MASTER CLASS](http://www.baeldung.com/rest-with-spring-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=rws#master-class)**
 
-And here's the Master Class of Learn Spring Security: <br/>
+Here's the new "Learn Spring" course: <br/>
-**[>> LEARN SPRING SECURITY - MASTER CLASS](http://www.baeldung.com/learn-spring-security-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=lss#master-class)**
+**[>> LEARN SPRING - THE MASTER CLASS](https://www.baeldung.com/learn-spring-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=ls#master-class)**
+
+Here's the Master Class of "REST With Spring" (along with the new announced Boot 2 material): <br/>
+**[>> THE REST WITH SPRING - MASTER CLASS](https://www.baeldung.com/rest-with-spring-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=rws#master-class)**
+
+And here's the Master Class of "Learn Spring Security": <br/>
+**[>> LEARN SPRING SECURITY - MASTER CLASS](https://www.baeldung.com/learn-spring-security-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=lss#master-class)**
 
 
 
@@ -15,7 +19,7 @@ Java and Spring Tutorials
 
 This project is **a collection of small and focused tutorials** - each covering a single and well defined area of development in the Java ecosystem. 
 A strong focus of these is, of course, the Spring Framework - Spring, Spring Boot and Spring Security. 
-In additional to Spring, the following technologies are in focus: `core Java`, `Jackson`, `HttpClient`, `Guava`. 
+In additional to Spring, the modules here are covering a number of aspects in Java. 
 
 
 Building the project
@@ -32,8 +36,15 @@ Running a Spring Boot module
 ====================
 To run a Spring Boot module run the command: `mvn spring-boot:run` in the module directory
 
-#Running Tests
 
+Working with the IDE
+====================
+This repo contains a large number of modules. 
+When you're working with an individual module, there's no need to import all of them (or build all of them) - you can simply import that particular module in either Eclipse or IntelliJ. 
+
+
+Running Tests
+=============
 The command `mvn clean install` will run the unit tests in a module.
 To run the integration tests, use the command `mvn clean install -Pintegration-lite-first`
 

algorithms-miscellaneous-3/README.md

@@ -1,4 +1,4 @@
-## Relevant articles:
+## Relevant Articles:
 
 - [Java Two Pointer Technique](https://www.baeldung.com/java-two-pointer-technique)
 - [Implementing Simple State Machines with Java Enums](https://www.baeldung.com/java-enum-simple-state-machine)
@@ -6,4 +6,4 @@
 - [Practical Java Examples of the Big O Notation](http://www.baeldung.com/java-algorithm-complexity)
 - [Checking If a List Is Sorted in Java](https://www.baeldung.com/java-check-if-list-sorted)
 - [Checking if a Java Graph has a Cycle](https://www.baeldung.com/java-graph-has-a-cycle)
-- [A Guide to the Folding Technique](https://www.baeldung.com/folding-hashing-technique)
+- [A Guide to the Folding Technique in Java](https://www.baeldung.com/folding-hashing-technique)

algorithms-miscellaneous-3/src/main/java/com/baeldung/algorithms/stringsortingbynumber/NaturalOrderComparators.java

@@ -0,0 +1,30 @@
+package com.baeldung.algorithms.stringsortingbynumber;
+
+import java.util.Comparator;
+
+public final class NaturalOrderComparators {
+
+    private static final String DIGIT_AND_DECIMAL_REGEX = "[^\\d.]";
+
+    private NaturalOrderComparators() {
+        throw new AssertionError("Let's keep this static");
+    }
+
+    public static Comparator<String> createNaturalOrderRegexComparator() {
+        return Comparator.comparingDouble(NaturalOrderComparators::parseStringToNumber);
+    }
+
+    private static double parseStringToNumber(String input){
+
+        final String digitsOnly = input.replaceAll(DIGIT_AND_DECIMAL_REGEX, "");
+
+        if("".equals(digitsOnly)) return 0;
+
+        try{
+            return Double.parseDouble(digitsOnly);
+        }catch (NumberFormatException nfe){
+            return 0;
+        }
+    }
+
+}

algorithms-miscellaneous-3/src/test/java/com/baeldung/algorithms/stringsortingbynumber/NaturalOrderComparatorsUnitTest.java

@@ -0,0 +1,79 @@
+package com.baeldung.algorithms.stringsortingbynumber;
+
+import com.baeldung.algorithms.stringsortingbynumber.NaturalOrderComparators;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.junit.Assert.*;
+
+public class NaturalOrderComparatorsUnitTest {
+
+    @Test
+    public void givenSimpleStringsContainingIntsAndDoubles_whenSortedByRegex_checkSortingCorrect() {
+
+        List<String> testStrings = Arrays.asList("a1", "b3", "c4", "d2.2", "d2.4", "d2.3d");
+
+        testStrings.sort(NaturalOrderComparators.createNaturalOrderRegexComparator());
+
+        List<String> expected = Arrays.asList("a1", "d2.2", "d2.3d", "d2.4", "b3", "c4");
+
+        assertEquals(expected, testStrings);
+
+
+    }
+
+    @Test
+    public void givenSimpleStringsContainingIntsAndDoublesWithAnInvalidNumber_whenSortedByRegex_checkSortingCorrect() {
+
+        List<String> testStrings = Arrays.asList("a1", "b3", "c4", "d2.2", "d2.4", "d2.3.3d");
+
+        testStrings.sort(NaturalOrderComparators.createNaturalOrderRegexComparator());
+
+        List<String> expected = Arrays.asList("d2.3.3d", "a1", "d2.2", "d2.4", "b3", "c4");
+
+        assertEquals(expected, testStrings);
+
+
+    }
+
+    @Test
+    public void givenAllForseenProblems_whenSortedByRegex_checkSortingCorrect() {
+
+        List<String> testStrings = Arrays.asList("a1", "b3", "c4", "d2.2", "d2.f4", "d2.3.3d");
+
+        testStrings.sort(NaturalOrderComparators.createNaturalOrderRegexComparator());
+
+        List<String> expected = Arrays.asList("d2.3.3d", "a1", "d2.2", "d2.f4", "b3", "c4");
+
+        assertEquals(expected, testStrings);
+
+
+    }
+
+    @Test
+    public void givenComplexStringsContainingSeparatedNumbers_whenSortedByRegex_checkNumbersCondensedAndSorted() {
+
+        List<String> testStrings = Arrays.asList("a1b2c5", "b3ght3.2", "something65.thensomething5"); //125, 33.2, 65.5
+
+        List<String> expected = Arrays.asList("b3ght3.2", "something65.thensomething5", "a1b2c5" );
+
+        testStrings.sort(NaturalOrderComparators.createNaturalOrderRegexComparator());
+
+        assertEquals(expected, testStrings);
+
+    }
+
+    @Test
+    public void givenStringsNotContainingNumbers_whenSortedByRegex_checkOrderNotChanged() {
+
+        List<String> testStrings = Arrays.asList("a", "c", "d", "e");
+        List<String> expected = new ArrayList<>(testStrings);
+
+        testStrings.sort(NaturalOrderComparators.createNaturalOrderRegexComparator());
+
+        assertEquals(expected, testStrings);
+    }
+}

algorithms-sorting/src/main/java/com/baeldung/algorithms/shellsort/ShellSort.java

@@ -0,0 +1,20 @@
+package com.baeldung.algorithms.shellsort;
+
+public class ShellSort {
+
+    public static void sort(int arrayToSort[]) {
+        int n = arrayToSort.length;
+
+        for (int gap = n / 2; gap > 0; gap /= 2) {
+            for (int i = gap; i < n; i++) {
+                int key = arrayToSort[i];
+                int j = i;
+                while (j >= gap && arrayToSort[j - gap] > key) {
+                    arrayToSort[j] = arrayToSort[j - gap];
+                    j -= gap;
+                }
+                arrayToSort[j] = key;
+            }
+        }
+    }
+}

algorithms-sorting/src/test/java/com/baeldung/algorithms/shellsort/ShellSortUnitTest.java

@@ -0,0 +1,17 @@
+package com.baeldung.algorithms.shellsort;
+
+import static org.junit.Assert.*;
+import static org.junit.Assert.assertArrayEquals;
+
+import org.junit.Test;
+
+public class ShellSortUnitTest {
+
+    @Test
+    public void givenUnsortedArray_whenShellSort_thenSortedAsc() {
+        int[] input = {41, 15, 82, 5, 65, 19, 32, 43, 8};
+        ShellSort.sort(input);
+        int[] expected = {5, 8, 15, 19, 32, 41, 43, 65, 82};
+        assertArrayEquals("the two arrays are not equal", expected, input);
+    }
+}

apache-olingo/olingo2/pom.xml

@@ -82,7 +82,6 @@
 	</build>
 
 	<properties>
-		<java.version>1.8</java.version>
 		<olingo2.version>2.0.11</olingo2.version>
 	</properties>
 

aws/pom.xml

@@ -112,7 +112,6 @@
     </repositories>
 
     <properties>
-        <commons-io.version>2.5</commons-io.version>
         <aws-lambda-java-events.version>1.3.0</aws-lambda-java-events.version>
         <aws-lambda-java-core.version>1.1.0</aws-lambda-java-core.version>
         <gson.version>2.8.0</gson.version>

axon/pom.xml

@@ -18,12 +18,6 @@
             <groupId>org.axonframework</groupId>
             <artifactId>axon-spring-boot-starter</artifactId>
             <version>${axon.version}</version>
-            <exclusions>
-                <exclusion>
-                    <groupId>org.axonframework</groupId>
-                    <artifactId>axon-server-connector</artifactId>
-                </exclusion>
-            </exclusions>
         </dependency>
 
         <dependency>
@@ -58,7 +52,7 @@
     </dependencies>
 
     <properties>
-        <axon.version>4.0.3</axon.version>
+        <axon.version>4.1.2</axon.version>
     </properties>
 
 </project>

axon/src/main/java/com/baeldung/axon/commandmodel/OrderAggregate.java

@@ -13,6 +13,7 @@ import com.baeldung.axon.coreapi.commands.ShipOrderCommand;
 import com.baeldung.axon.coreapi.events.OrderConfirmedEvent;
 import com.baeldung.axon.coreapi.events.OrderPlacedEvent;
 import com.baeldung.axon.coreapi.events.OrderShippedEvent;
+import com.baeldung.axon.coreapi.exceptions.UnconfirmedOrderException;
 
 @Aggregate
 public class OrderAggregate {
@@ -34,7 +35,7 @@ public class OrderAggregate {
     @CommandHandler
     public void handle(ShipOrderCommand command) {
         if (!orderConfirmed) {
-            throw new IllegalStateException("Cannot ship an order which has not been confirmed yet.");
+            throw new UnconfirmedOrderException();
         }
 
         apply(new OrderShippedEvent(orderId));
@@ -43,12 +44,12 @@ public class OrderAggregate {
     @EventSourcingHandler
     public void on(OrderPlacedEvent event) {
         this.orderId = event.getOrderId();
-        orderConfirmed = false;
+        this.orderConfirmed = false;
     }
 
     @EventSourcingHandler
     public void on(OrderConfirmedEvent event) {
-        orderConfirmed = true;
+        this.orderConfirmed = true;
     }
 
     protected OrderAggregate() {

axon/src/main/java/com/baeldung/axon/coreapi/exceptions/UnconfirmedOrderException.java

@@ -0,0 +1,8 @@
+package com.baeldung.axon.coreapi.exceptions;
+
+public class UnconfirmedOrderException extends IllegalStateException {
+
+    public UnconfirmedOrderException() {
+        super("Cannot ship an order which has not been confirmed yet.");
+    }
+}

axon/src/main/java/com/baeldung/axon/querymodel/OrderedProductsEventHandler.java

@@ -5,6 +5,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.axonframework.config.ProcessingGroup;
 import org.axonframework.eventhandling.EventHandler;
 import org.axonframework.queryhandling.QueryHandler;
 import org.springframework.stereotype.Service;
@@ -16,6 +17,7 @@ import com.baeldung.axon.coreapi.queries.FindAllOrderedProductsQuery;
 import com.baeldung.axon.coreapi.queries.OrderedProduct;
 
 @Service
+@ProcessingGroup("ordered-products")
 public class OrderedProductsEventHandler {
 
     private final Map<String, OrderedProduct> orderedProducts = new HashMap<>();

axon/src/main/resources/application.properties

@@ -0,0 +1 @@
+spring.application.name=Order Management Service

axon/src/test/java/com/baeldung/axon/commandmodel/OrderAggregateUnitTest.java

@@ -2,6 +2,7 @@ package com.baeldung.axon.commandmodel;
 
 import java.util.UUID;
 
+import com.baeldung.axon.coreapi.exceptions.UnconfirmedOrderException;
 import org.axonframework.test.aggregate.AggregateTestFixture;
 import org.axonframework.test.aggregate.FixtureConfiguration;
 import org.junit.*;
@@ -41,12 +42,12 @@ public class OrderAggregateUnitTest {
     }
 
     @Test
-    public void givenOrderPlacedEvent_whenShipOrderCommand_thenShouldThrowIllegalStateException() {
+    public void givenOrderPlacedEvent_whenShipOrderCommand_thenShouldThrowUnconfirmedOrderException() {
         String orderId = UUID.randomUUID().toString();
         String product = "Deluxe Chair";
         fixture.given(new OrderPlacedEvent(orderId, product))
                .when(new ShipOrderCommand(orderId))
-               .expectException(IllegalStateException.class);
+               .expectException(UnconfirmedOrderException.class);
     }
 
     @Test

core-groovy-2/pom.xml

@@ -175,8 +175,6 @@
         <junit.platform.version>1.0.0</junit.platform.version>
         <hsqldb.version>2.4.0</hsqldb.version>
         <spock-core.version>1.1-groovy-2.4</spock-core.version>
-        <commons-lang3.version>3.9</commons-lang3.version>
-        <java.version>1.8</java.version>
         <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
         <logback.version>1.2.3</logback.version>
         <groovy.version>2.5.7</groovy.version>

core-groovy-2/src/main/groovy/com/baeldung/concatenate/Wonder.groovy

@@ -0,0 +1,52 @@
+package com.baeldung.concatenate
+
+class Wonder {
+
+    String numOfWonder = 'seven'
+
+    String operator_plus() {
+        return 'The ' + numOfWonder + ' wonders of the world'
+    }
+
+    String operator_left() {
+        return 'The ' << numOfWonder << ' wonders of ' << 'the world'
+    }
+
+    String interpolation_one() {
+        return "The $numOfWonder wonders of the world"
+
+    }
+
+    String interpolation_two() {
+        return "The ${numOfWonder} wonders of the world"
+    }
+
+    String multilineString() {
+        return """
+            There are $numOfWonder wonders of the world.
+            Can you name them all? 
+            1. The Great Pyramid of Giza
+            2. Hanging Gardens of Babylon
+            3. Colossus of Rhode
+            4. Lighthouse of Alexendra
+            5. Temple of Artemis
+            6. Status of Zeus at Olympia
+            7. Mausoleum at Halicarnassus
+        """
+    }
+
+    String method_concat() {
+        return 'The '.concat(numOfWonder).concat(' wonders of the world')
+
+    }
+
+    String method_builder() {
+        return new StringBuilder()
+                .append('The ').append(numOfWonder).append(' wonders of the world')
+    }
+
+    String method_buffer() {
+        return new StringBuffer()
+                .append('The ').append(numOfWonder).append(' wonders of the world')
+    }
+}

core-groovy-2/src/main/groovy/com/baeldung/metaprogramming/Employee.groovy

@@ -0,0 +1,45 @@
+package com.baeldung.metaprogramming
+
+import groovy.transform.AutoClone
+import groovy.transform.Canonical
+import groovy.transform.EqualsAndHashCode
+import groovy.transform.ToString
+import groovy.transform.TupleConstructor
+import groovy.util.logging.*
+
+@Canonical
+@TupleConstructor
+@EqualsAndHashCode
+@ToString(includePackage=false, excludes=['id'])
+@Log 
+@AutoClone
+class Employee {
+
+    long id
+    String firstName
+    String lastName
+    int age
+
+    //method to catch missing property's getter
+    def propertyMissing(String propertyName) {
+        log.info "$propertyName is not available"
+        "property '$propertyName' is not available"
+    }
+
+    //method to catch missing property's setter
+    def propertyMissing(String propertyName, propertyValue) {
+        println "property '$propertyName' is not available"
+        log.info "$propertyName is not available"
+        "property '$propertyName' is not available"
+    }
+
+    def methodMissing(String methodName, def methodArgs) {
+        log.info "$methodName is not defined"
+        "method '$methodName' is not defined"
+    }
+    
+    def logEmp() {
+        log.info "Employee: $lastName, $firstName is of $age years age"
+    }
+
+}

core-groovy-2/src/main/groovy/com/baeldung/metaprogramming/extension/BasicExtensions.groovy

@@ -0,0 +1,30 @@
+package com.baeldung.metaprogramming.extension
+
+import com.baeldung.metaprogramming.Employee
+
+class BasicExtensions {
+    
+    static int getYearOfBirth(Employee self) {
+        return (new Date().getYear() + 1900) - self.age;
+    }
+    
+    static String capitalize(String self) {
+        return self.substring(0, 1).toUpperCase() + self.substring(1)
+    }
+
+    static void printCounter(Integer self) {
+        while (self>0) {
+            println self
+            self--
+        }
+    }
+    
+    static Long square(Long self) {
+        return self*self
+    }
+    
+    static BigDecimal cube(BigDecimal self) {
+        return self*self*self
+    }
+    
+}

core-groovy-2/src/main/groovy/com/baeldung/metaprogramming/extension/StaticEmployeeExtension.groovy

@@ -0,0 +1,10 @@
+package com.baeldung.metaprogramming.extension
+
+import com.baeldung.metaprogramming.Employee
+
+class StaticEmployeeExtension {
+    
+    static Employee getDefaultObj(Employee self) {
+        return new Employee(firstName: "firstName", lastName: "lastName", age: 20)
+    }
+}

core-groovy-2/src/main/resources/META-INF/services/org.codehaus.groovy.runtime.ExtensionModule

@@ -0,0 +1,4 @@
+moduleName=core-groovy-2
+moduleVersion=1.0-SNAPSHOT
+extensionClasses=com.baeldung.metaprogramming.extension.BasicExtensions
+staticExtensionClasses=com.baeldung.metaprogramming.extension.StaticEmployeeExtension

core-groovy-2/src/test/groovy/com/baeldung/concatenate/WonderUnitTest.groovy

@@ -0,0 +1,69 @@
+package com.baeldung.concatenate
+
+import org.junit.Before
+import org.junit.Test
+
+import static org.junit.Assert.*
+
+class WonderUnitTest {
+
+    static final String EXPECTED_SINGLE_LINE = "The seven wonders of the world"
+
+    Wonder wonder
+
+    @Before
+    void before() {
+        wonder = new Wonder()
+    }
+
+    @Test
+    void whenUsingOperatorPlus_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.operator_plus())
+    }
+
+    @Test
+    void whenUsingOperatorLeft_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.operator_left())
+    }
+
+    @Test
+    void whenUsingInterpolationOne_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.interpolation_one())
+    }
+
+    @Test
+    void whenUsingInterpolationTwo_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.interpolation_two())
+    }
+
+    @Test
+    void whenUsingMultiline_thenConcatCorrectly() {
+        def expectedMultiline = """
+            There are seven wonders of the world.
+            Can you name them all? 
+            1. The Great Pyramid of Giza
+            2. Hanging Gardens of Babylon
+            3. Colossus of Rhode
+            4. Lighthouse of Alexendra
+            5. Temple of Artemis
+            6. Status of Zeus at Olympia
+            7. Mausoleum at Halicarnassus
+        """
+        assertEquals(expectedMultiline, wonder.multilineString())
+    }
+
+    @Test
+    void whenUsingMethodConcat_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.method_concat())
+    }
+
+    @Test
+    void whenUsingMethodBuilder_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.method_builder())
+    }
+
+    @Test
+    void whenUsingMethodBuffer_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.method_buffer())
+    }
+}

core-groovy-2/src/test/groovy/com/baeldung/metaprogramming/MetaprogrammingUnitTest.groovy

@@ -0,0 +1,118 @@
+package com.baeldung.metaprogramming
+
+import groovy.time.TimeCategory
+
+class MetaprogrammingUnitTest extends GroovyTestCase {
+
+    Employee emp = new Employee(firstName: "Norman", lastName: "Lewis")
+
+    void testPropertyMissing() {
+        assert emp.address == "property 'address' is not available"
+    }
+
+    void testMethodMissing() {
+        Employee emp = new Employee()
+        try {
+            emp.getFullName()
+        } catch(MissingMethodException e) {
+            println "method is not defined"
+        }
+        assert emp.getFullName() == "method 'getFullName' is not defined"
+    }
+
+    void testMetaClassProperty() {
+        Employee.metaClass.address = ""
+        emp = new Employee(firstName: "Norman", lastName: "Lewis", address: "US")
+        assert emp.address == "US"
+    }
+
+    void testMetaClassMethod() {
+        emp.metaClass.getFullName = {
+            "$lastName, $firstName"
+        }
+        assert emp.getFullName() == "Lewis, Norman"
+    }
+
+    void testMetaClassConstructor() {
+        try {
+            Employee emp = new Employee("Norman")
+        } catch(GroovyRuntimeException e) {
+            assert e.message == "Could not find matching constructor for: com.baeldung.metaprogramming.Employee(String)"
+        }
+
+        Employee.metaClass.constructor = { String firstName ->
+            new Employee(firstName: firstName)
+        }
+
+        Employee norman = new Employee("Norman")
+        assert norman.firstName == "Norman"
+        assert norman.lastName == null
+    }
+
+    void testJavaMetaClass() {
+        String.metaClass.capitalize = { String str ->
+            str.substring(0, 1).toUpperCase() + str.substring(1);
+        }
+        assert "norman".capitalize() == "Norman"
+    }
+
+    void testEmployeeExtension() {
+        Employee emp = new Employee(age: 28)
+        assert emp.getYearOfBirth() == 1991
+    }
+
+    void testJavaClassesExtensions() {
+        5.printCounter()
+
+        assert 40l.square() == 1600l
+
+        assert (2.98).cube() == 26.463592
+    }
+
+    void testStaticEmployeeExtension() {
+        assert Employee.getDefaultObj().firstName == "firstName"
+        assert Employee.getDefaultObj().lastName == "lastName"
+        assert Employee.getDefaultObj().age == 20
+    }
+
+    void testToStringAnnotation() {
+        Employee employee = new Employee()
+        employee.id = 1
+        employee.firstName = "norman"
+        employee.lastName = "lewis"
+        employee.age = 28
+
+        assert employee.toString() == "Employee(norman, lewis, 28)"
+    }
+
+    void testTupleConstructorAnnotation() {
+        Employee norman = new Employee(1, "norman", "lewis", 28)
+        assert norman.toString() == "Employee(norman, lewis, 28)"
+
+        Employee snape = new Employee(2, "snape")
+        assert snape.toString() == "Employee(snape, null, 0)"
+
+    }
+    
+    void testEqualsAndHashCodeAnnotation() {
+        Employee norman = new Employee(1, "norman", "lewis", 28)
+        Employee normanCopy = new Employee(1, "norman", "lewis", 28)
+        assert norman.equals(normanCopy)
+        assert norman.hashCode() == normanCopy.hashCode()
+    }
+    
+    void testAutoCloneAnnotation() {
+        try {
+            Employee norman = new Employee(1, "norman", "lewis", 28)
+            def normanCopy = norman.clone()
+            assert norman == normanCopy
+        } catch(CloneNotSupportedException e) {
+            e.printStackTrace()
+        }
+    }
+
+    void testLoggingAnnotation() {
+        Employee employee = new Employee(1, "Norman", "Lewis", 28)
+        employee.logEmp()
+    }
+}

core-java-modules/core-java-11/src/main/java/com/baeldung/predicate/not/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Negate a Predicate Method Reference with Java 11](https://www.baeldung.com/java-negate-predicate-method-reference)

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

@@ -0,0 +1,4 @@
+## Relevant Articles:
+
+
+- [String API Updates in Java 12](https://www.baeldung.com/java12-string-api)

core-java-modules/core-java-8-2/README.md

@@ -7,3 +7,4 @@
 - [How to Delay Code Execution in Java](https://www.baeldung.com/java-delay-code-execution)
 - [Run JAR Application With Command Line Arguments](https://www.baeldung.com/java-run-jar-with-arguments)
 - [Java 8 Stream skip() vs limit()](https://www.baeldung.com/java-stream-skip-vs-limit)
+- [Guide to Java BiFunction Interface](https://www.baeldung.com/java-bifunction-interface)

core-java-modules/core-java-8/pom.xml

@@ -175,7 +175,6 @@
 
     <properties>
         <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-math3.version>3.6.1</commons-math3.version>
         <commons-collections4.version>4.1</commons-collections4.version>
         <collections-generic.version>4.01</collections-generic.version>

core-java-modules/core-java-8/src/main/java/com/baeldung/java_8_features/groupingby/Tuple.java

@@ -0,0 +1,34 @@
+package com.baeldung.java_8_features.groupingby;
+
+public class Tuple {
+
+    private BlogPostType type;
+    private String author;
+    
+    public Tuple(BlogPostType type, String author) {
+        super();
+        this.type = type;
+        this.author = author;
+    }
+
+    public BlogPostType getType() {
+        return type;
+    }
+
+    public void setType(BlogPostType type) {
+        this.type = type;
+    }
+
+    public String getAuthor() {
+        return author;
+    }
+
+    public void setAuthor(String author) {
+        this.author = author;
+    }
+
+    @Override
+    public String toString() {
+        return "Tuple [type=" + type + ", author=" + author + ", getType()=" + getType() + ", getAuthor()=" + getAuthor() + ", getClass()=" + getClass() + ", hashCode()=" + hashCode() + ", toString()=" + super.toString() + "]";
+    }
+}

core-java-modules/core-java-8/src/test/java/com/baeldung/java8/optional/OptionalUnitTest.java

@@ -259,4 +259,15 @@ public class OptionalUnitTest {
         LOG.debug("Getting default value...");
         return "Default Value";
     }
+    
+//    Uncomment code when code base is compatiable with Java 11     
+//    @Test
+//    public void givenAnEmptyOptional_thenIsEmptyBehavesAsExpected() {
+//        Optional<String> opt = Optional.of("Baeldung");
+//        assertFalse(opt.isEmpty());
+//     
+//        opt = Optional.ofNullable(null);
+//        assertTrue(opt.isEmpty());
+//    }
+
 }

core-java-modules/core-java-arrays-2/.gitignore

@@ -0,0 +1,25 @@
+*.class
+
+0.*
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+.resourceCache
+
+# Packaged files #
+*.jar
+*.war
+*.ear
+
+# Files generated by integration tests
+backup-pom.xml
+/bin/
+/temp
+
+#IntelliJ specific
+.idea/
+*.iml