Merge pull request #76 from eugenp/master

update

README.md

@@ -1,5 +1,3 @@
-**UPDATE**: The price of "Learn Spring Security OAuth" will permanently change on the 11th of December, along with the upcoming OAuth2 material: http://bit.ly/github-lss
-
 The Courses
 ==============================
 

algorithms-genetic/README.md

@@ -5,6 +5,6 @@ This module contains articles about genetic algorithms.
 ### Relevant articles:
 
 - [Introduction to Jenetics Library](https://www.baeldung.com/jenetics)
-- [Ant Colony Optimization](https://www.baeldung.com/java-ant-colony-optimization)
+- [Ant Colony Optimization with a Java Example](https://www.baeldung.com/java-ant-colony-optimization)
 - [Design a Genetic Algorithm in Java](https://www.baeldung.com/java-genetic-algorithm)
 - [The Traveling Salesman Problem in Java](https://www.baeldung.com/java-simulated-annealing-for-traveling-salesman)

algorithms-miscellaneous-1/README.md

@@ -6,8 +6,8 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
 ### Relevant articles:
 
 - [Validating Input With Finite Automata in Java](https://www.baeldung.com/java-finite-automata)
-- [Example of Hill Climbing Algorithm](https://www.baeldung.com/java-hill-climbing-algorithm)
-- [Introduction to Minimax Algorithm](https://www.baeldung.com/java-minimax-algorithm)
+- [Example of Hill Climbing Algorithm in Java](https://www.baeldung.com/java-hill-climbing-algorithm)
+- [Introduction to Minimax Algorithm with a Java Implementation](https://www.baeldung.com/java-minimax-algorithm)
 - [How to Calculate Levenshtein Distance in Java?](https://www.baeldung.com/java-levenshtein-distance)
 - [How to Find the Kth Largest Element in Java](https://www.baeldung.com/java-kth-largest-element)
 - More articles: [[next -->]](/algorithms-miscellaneous-2)

algorithms-miscellaneous-4/README.md

@@ -5,8 +5,8 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
 ### Relevant articles:
 
 - [Multi-Swarm Optimization Algorithm in Java](https://www.baeldung.com/java-multi-swarm-algorithm)
-- [Check If a String Contains All The Letters of The Alphabet](https://www.baeldung.com/java-string-contains-all-letters)
-- [Find the Middle Element of a Linked List](https://www.baeldung.com/java-linked-list-middle-element)
+- [Check If a String Contains All The Letters of The Alphabet with Java](https://www.baeldung.com/java-string-contains-all-letters)
+- [Find the Middle Element of a Linked List in Java](https://www.baeldung.com/java-linked-list-middle-element)
 - [Find Substrings That Are Palindromes in Java](https://www.baeldung.com/java-palindrome-substrings)
 - [Find the Longest Substring without Repeating Characters](https://www.baeldung.com/java-longest-substring-without-repeated-characters)
 - [Permutations of an Array in Java](https://www.baeldung.com/java-array-permutations)

algorithms-miscellaneous-5/README.md

@@ -9,11 +9,11 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
 - [Reversing a Binary Tree in Java](https://www.baeldung.com/java-reversing-a-binary-tree)
 - [Find If Two Numbers Are Relatively Prime in Java](https://www.baeldung.com/java-two-relatively-prime-numbers)
 - [Knapsack Problem Implementation in Java](https://www.baeldung.com/java-knapsack)
-- [How to Determine if a Binary Tree is Balanced](https://www.baeldung.com/java-balanced-binary-tree)
+- [How to Determine if a Binary Tree is Balanced in Java](https://www.baeldung.com/java-balanced-binary-tree)
 - [Overview of Combinatorial Problems in Java](https://www.baeldung.com/java-combinatorial-algorithms)
-- [Prim’s Algorithm](https://www.baeldung.com/java-prim-algorithm)
-- [Maximum Subarray Problem](https://www.baeldung.com/java-maximum-subarray)
-- [How to Merge Two Sorted Arrays](https://www.baeldung.com/java-merge-sorted-arrays)
-- [Median of Stream of Integers using Heap](https://www.baeldung.com/java-stream-integers-median-using-heap)
+- [Prim’s Algorithm with a Java Implementation](https://www.baeldung.com/java-prim-algorithm)
+- [Maximum Subarray Problem in Java](https://www.baeldung.com/java-maximum-subarray)
+- [How to Merge Two Sorted Arrays in Java](https://www.baeldung.com/java-merge-sorted-arrays)
+- [Median of Stream of Integers using Heap in Java](https://www.baeldung.com/java-stream-integers-median-using-heap)
 - More articles: [[<-- prev]](/algorithms-miscellaneous-4) [[next -->]](/algorithms-miscellaneous-6)
 

algorithms-miscellaneous-6/README.md

@@ -1,13 +1,13 @@
 ### Relevant Articles:
 
-- [Boruvka’s Algorithm for Minimum Spanning Trees](https://www.baeldung.com/java-boruvka-algorithm)
+- [Boruvka’s Algorithm for Minimum Spanning Trees in Java](https://www.baeldung.com/java-boruvka-algorithm)
 - [Gradient Descent in Java](https://www.baeldung.com/java-gradient-descent)
-- [Kruskal’s Algorithm for Spanning Trees](https://www.baeldung.com/java-spanning-trees-kruskal)
+- [Kruskal’s Algorithm for Spanning Trees with a Java Implementation](https://www.baeldung.com/java-spanning-trees-kruskal)
 - [Balanced Brackets Algorithm in Java](https://www.baeldung.com/java-balanced-brackets-algorithm)
 - [Efficiently Merge Sorted Java Sequences](https://www.baeldung.com/java-merge-sorted-sequences)
 - [Introduction to Greedy Algorithms with Java](https://www.baeldung.com/java-greedy-algorithms)
 - [The Caesar Cipher in Java](https://www.baeldung.com/java-caesar-cipher)
 - [Implementing a 2048 Solver in Java](https://www.baeldung.com/2048-java-solver)
-- [Finding Top K Elements in an Array](https://www.baeldung.com/java-array-top-elements)
+- [Finding Top K Elements in a Java Array](https://www.baeldung.com/java-array-top-elements)
 - [Reversing a Linked List in Java](https://www.baeldung.com/java-reverse-linked-list)
 - More articles: [[<-- prev]](/algorithms-miscellaneous-5)

algorithms-searching/README.md

@@ -8,8 +8,8 @@ This module contains articles about searching algorithms.
 - [Depth First Search in Java](https://www.baeldung.com/java-depth-first-search)
 - [Interpolation Search in Java](https://www.baeldung.com/java-interpolation-search)
 - [Breadth-First Search Algorithm in Java](https://www.baeldung.com/java-breadth-first-search)
-- [String Search Algorithms for Large Texts](https://www.baeldung.com/java-full-text-search-algorithms)
-- [Monte Carlo Tree Search for Tic-Tac-Toe Game](https://www.baeldung.com/java-monte-carlo-tree-search)
+- [String Search Algorithms for Large Texts with Java](https://www.baeldung.com/java-full-text-search-algorithms)
+- [Monte Carlo Tree Search for Tic-Tac-Toe Game in Java](https://www.baeldung.com/java-monte-carlo-tree-search)
 - [Range Search Algorithm in Java](https://www.baeldung.com/java-range-search)
-- [Fast Pattern Matching of Strings Using Suffix Tree](https://www.baeldung.com/java-pattern-matching-suffix-tree)
-- [Find the Kth Smallest Element in Two Sorted Arrays](https://www.baeldung.com/java-kth-smallest-element-in-sorted-arrays)
+- [Fast Pattern Matching of Strings Using Suffix Tree in Java](https://www.baeldung.com/java-pattern-matching-suffix-tree)
+- [Find the Kth Smallest Element in Two Sorted Arrays in Java](https://www.baeldung.com/java-kth-smallest-element-in-sorted-arrays)

algorithms-sorting-2/README.md

@@ -2,6 +2,6 @@
 
 - [Sorting a String Alphabetically in Java](https://www.baeldung.com/java-sort-string-alphabetically)
 - [Sorting Strings by Contained Numbers in Java](https://www.baeldung.com/java-sort-strings-contained-numbers)
-- [How an In-Place Sorting Algorithm Works](https://www.baeldung.com/java-in-place-sorting)
-- [Partitioning and Sorting Arrays with Many Repeated Entries](https://www.baeldung.com/java-sorting-arrays-with-repeated-entries)
+- [Guide to In-Place Sorting Algorithm Works with a Java Implementation](https://www.baeldung.com/java-in-place-sorting)
+- [Partitioning and Sorting Arrays with Many Repeated Entries with Java Examples](https://www.baeldung.com/java-sorting-arrays-with-repeated-entries)
 - More articles: [[<-- prev]](/algorithms-sorting)

atomikos/pom.xml

@@ -51,7 +51,7 @@
 		</dependency>
 		<dependency>
 			<groupId>org.hibernate</groupId>
-			<artifactId>hibernate-entitymanager</artifactId>
+			<artifactId>hibernate-core</artifactId>
 			<version>${hibernate.version}</version>
 			<scope>provided</scope>
 			<exclusions>

aws-lambda/shipping-tracker/ShippingFunction/src/main/java/com/baeldung/lambda/shipping/App.java

@@ -6,10 +6,12 @@ import com.amazonaws.services.lambda.runtime.events.APIGatewayProxyRequestEvent;
 import com.amazonaws.services.lambda.runtime.events.APIGatewayProxyResponseEvent;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.zaxxer.hikari.HikariDataSource;
 import org.hibernate.SessionFactory;
 import org.hibernate.boot.MetadataSources;
 import org.hibernate.boot.registry.StandardServiceRegistry;
 import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
+import org.hibernate.engine.jdbc.connections.spi.ConnectionProvider;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -22,11 +24,14 @@ import static org.hibernate.cfg.AvailableSettings.PASS;
  */
 public class App implements RequestHandler<APIGatewayProxyRequestEvent, APIGatewayProxyResponseEvent> {
 private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
+    private SessionFactory sessionFactory = createSessionFactory();
 
     public APIGatewayProxyResponseEvent handleRequest(APIGatewayProxyRequestEvent input, Context context) {
-        try (SessionFactory sessionFactory = createSessionFactory()) {
+        try {
             ShippingService service = new ShippingService(sessionFactory, new ShippingDao());
             return routeRequest(input, service);
+        } finally {
+            flushConnectionPool();
         }
     }
 
@@ -105,4 +110,12 @@ private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
           .buildMetadata()
           .buildSessionFactory();
     }
+
+    private void flushConnectionPool() {
+        ConnectionProvider connectionProvider = sessionFactory.getSessionFactoryOptions()
+          .getServiceRegistry()
+          .getService(ConnectionProvider.class);
+        HikariDataSource hikariDataSource = connectionProvider.unwrap(HikariDataSource.class);
+        hikariDataSource.getHikariPoolMXBean().softEvictConnections();
+    }
 }

core-java-modules/core-java-10/README.md

@@ -10,3 +10,4 @@ This module contains articles about Java 10 core features
 - [Deep Dive Into the New Java JIT Compiler – Graal](https://www.baeldung.com/graal-java-jit-compiler)
 - [Copying Sets in Java](https://www.baeldung.com/java-copy-sets)
 - [Converting between a List and a Set in Java](https://www.baeldung.com/convert-list-to-set-and-set-to-list)
+- [Java IndexOutOfBoundsException “Source Does Not Fit in Dest”](https://www.baeldung.com/java-indexoutofboundsexception)

core-java-modules/core-java-14/README.md

@@ -10,3 +10,4 @@ This module contains articles about Java 14.
 - [Helpful NullPointerExceptions in Java 14](https://www.baeldung.com/java-14-nullpointerexception)
 - [Foreign Memory Access API in Java 14](https://www.baeldung.com/java-foreign-memory-access)
 - [Java 14 Record Keyword](https://www.baeldung.com/java-record-keyword)
+- [Java 14 – New Features](https://www.baeldung.com/java-14-new-features)

core-java-modules/core-java-14/src/test/java/com/baeldung/java14/character/IsLetterOrAlphabetUnitTest.java

@@ -0,0 +1,30 @@
+package com.baeldung.java14.character;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertFalse;
+
+public class IsLetterOrAlphabetUnitTest {
+
+    @Test
+    public void givenACharacter_whenLetter_thenAssertIsLetterTrue() {
+        assertTrue(Character.isLetter(65));
+    }
+
+    @Test
+    public void givenACharacter_whenLetter_thenAssertIsAlphabeticTrue() {
+        assertTrue(Character.isAlphabetic(65));
+    }
+
+    @Test
+    public void givenACharacter_whenAlphabeticAndNotLetter_thenAssertIsLetterFalse() {
+        assertFalse(Character.isLetter(837));
+    }
+
+    @Test
+    public void givenACharacter_whenAlphabeticAndNotLetter_thenAssertIsAlphabeticTrue() {
+        assertTrue(Character.isAlphabetic(837));
+    }
+
+}

core-java-modules/core-java-14/src/test/java/com/baeldung/java14/newfeatues/MultilineUnitTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.java14.newfeatues;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class MultilineUnitTest {
+    
+    @SuppressWarnings("preview")
+    String multiline = """ 
+            A quick brown fox jumps over a lazy dog; \
+         the lazy dog howls loudly.""";
+    
+    @SuppressWarnings("preview")
+    String anotherMultiline = """ 
+            A quick brown fox jumps over a lazy dog; 
+         the lazy dog howls loudly.""";
+    
+    @Test
+    public void givenMultilineString_whenSlashUsed_thenNoNewLine() {
+        assertFalse(multiline.contains("\n"));
+        assertTrue(anotherMultiline.contains("\n"));
+    }
+
+}

core-java-modules/core-java-14/src/test/java/com/baeldung/java14/newfeatues/RecordUnitTest.java

@@ -0,0 +1,38 @@
+package com.baeldung.java14.newfeatues;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class RecordUnitTest {
+
+    @SuppressWarnings("preview") 
+    public record User(int id, String password) {
+    };
+
+    private User user1 = new User(0, "UserOne");
+
+    @Test
+    public void givenRecord_whenObjInitialized_thenValuesCanBeFetchedWithGetters() {
+
+        assertEquals(0, user1.id());
+        assertEquals("UserOne", user1.password());
+    }
+
+    @Test
+    public void whenRecord_thenEqualsImplemented() {
+
+        User user2 = user1;
+
+        assertEquals(user1, user2);
+    }
+
+    @Test
+    public void whenRecord_thenToStringImplemented() {
+
+        assertTrue(user1.toString()
+            .contains("UserOne"));
+    }
+
+}

core-java-modules/core-java-14/src/test/java/com/baeldung/java14/newfeatues/SwitchExprUnitTest.java

@@ -0,0 +1,50 @@
+package com.baeldung.java14.newfeatues;
+
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class SwitchExprUnitTest {
+
+    @Test
+    public void givenDay_whenSunday_thenWeekend() {
+        assertTrue(isTodayHolidayInJava8("SUNDAY"));
+
+        assertTrue(isTodayHolidayInJava14("SUNDAY"));
+
+        assertThatExceptionOfType(IllegalArgumentException.class).isThrownBy(() -> isTodayHolidayInJava8("SOMEDAY"));
+
+        assertThatExceptionOfType(IllegalArgumentException.class).isThrownBy(() -> isTodayHolidayInJava14("SOMEDAY"));
+    }
+
+    private boolean isTodayHolidayInJava8(String day) {
+
+        boolean isTodayHoliday;
+        switch (day) {
+            case "MONDAY":
+            case "TUESDAY":
+            case "WEDNESDAY":
+            case "THURSDAY":
+            case "FRIDAY":
+                isTodayHoliday = false;
+                break;
+            case "SATURDAY":
+            case "SUNDAY":
+                isTodayHoliday = true;
+                break;
+            default:
+                throw new IllegalArgumentException("What's a " + day);
+        }
+        return isTodayHoliday;
+    }
+
+    private boolean isTodayHolidayInJava14(String day) {
+        return switch (day) {
+            case "MONDAY", "TUESDAY", "WEDNESDAY", "THURSDAY", "FRIDAY" -> false;
+            case "SATURDAY", "SUNDAY" -> true;
+            default -> throw new IllegalArgumentException("What's a " + day);
+        };
+    }
+
+}

core-java-modules/core-java-15/.mvn/jvm.config

@@ -0,0 +1 @@
+--enable-preview

core-java-modules/core-java-15/README.md

@@ -0,0 +1,7 @@
+## Core Java 15
+
+This module contains articles about Java 15. 
+
+### Relevant articles
+
+- [Sealed Classes and Interfaces in Java 15](https://www.baeldung.com/java-sealed-classes-interfaces)

core-java-modules/core-java-15/pom.xml

@@ -0,0 +1,77 @@
+<?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-15</artifactId>
+    <name>core-java-15</name>
+    <packaging>jar</packaging>
+    <url>http://maven.apache.org</url>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../pom.xml</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${apache-commons-lang3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <version>${junit-jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>${junit-jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <release>${maven.compiler.release}</release>
+                    <compilerArgs>--enable-preview</compilerArgs>
+                    <source>14</source>
+                    <target>14</target>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>${surefire.plugin.version}</version>
+                <configuration>
+                    <argLine>--enable-preview</argLine>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <maven.compiler.release>15</maven.compiler.release>
+        <apache-commons-lang3.version>3.11</apache-commons-lang3.version>
+        <assertj.version>3.17.2</assertj.version>
+        <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
+        <surefire.plugin.version>3.0.0-M3</surefire.plugin.version>
+    </properties>
+
+</project>

core-java-modules/core-java-15/src/main/java/com/baeldung/sealed/alternative/Vehicles.java

@@ -0,0 +1,49 @@
+package com.baeldung.sealed.alternative;
+
+public class Vehicles {
+
+    abstract static class Vehicle {
+
+        private final String registrationNumber;
+
+        public Vehicle(String registrationNumber) {
+            this.registrationNumber = registrationNumber;
+        }
+
+        public String getRegistrationNumber() {
+            return registrationNumber;
+        }
+
+    }
+
+    public static final class Car extends Vehicle {
+
+        private final int numberOfSeats;
+
+        public Car(int numberOfSeats, String registrationNumber) {
+            super(registrationNumber);
+            this.numberOfSeats = numberOfSeats;
+        }
+
+        public int getNumberOfSeats() {
+            return numberOfSeats;
+        }
+
+    }
+
+    public static final class Truck extends Vehicle {
+
+        private final int loadCapacity;
+
+        public Truck(int loadCapacity, String registrationNumber) {
+            super(registrationNumber);
+            this.loadCapacity = loadCapacity;
+        }
+
+        public int getLoadCapacity() {
+            return loadCapacity;
+        }
+
+    }
+
+}

core-java-modules/core-java-15/src/main/java/com/baeldung/sealed/classes/Car.java

@@ -0,0 +1,21 @@
+package com.baeldung.sealed.classes;
+
+public non-sealed class Car extends Vehicle implements Service {
+
+    private final int numberOfSeats;
+
+    public Car(int numberOfSeats, String registrationNumber) {
+        super(registrationNumber);
+        this.numberOfSeats = numberOfSeats;
+    }
+
+    public int getNumberOfSeats() {
+        return numberOfSeats;
+    }
+
+    @Override
+    public int getMaxServiceIntervalInMonths() {
+        return 12;
+    }
+
+}

core-java-modules/core-java-15/src/main/java/com/baeldung/sealed/classes/Service.java

@@ -0,0 +1,11 @@
+package com.baeldung.sealed.classes;
+
+public sealed interface Service permits Car, Truck {
+
+    int getMaxServiceIntervalInMonths();
+
+    default int getMaxDistanceBetweenServicesInKilometers() {
+        return 100000;
+    }
+
+}

core-java-modules/core-java-15/src/main/java/com/baeldung/sealed/classes/Truck.java

@@ -0,0 +1,21 @@
+package com.baeldung.sealed.classes;
+
+public final class Truck extends Vehicle implements Service {
+
+    private final int loadCapacity;
+
+    public Truck(int loadCapacity, String registrationNumber) {
+        super(registrationNumber);
+        this.loadCapacity = loadCapacity;
+    }
+
+    public int getLoadCapacity() {
+        return loadCapacity;
+    }
+
+    @Override
+    public int getMaxServiceIntervalInMonths() {
+        return 18;
+    }
+
+}

core-java-modules/core-java-15/src/main/java/com/baeldung/sealed/classes/Vehicle.java

@@ -0,0 +1,15 @@
+package com.baeldung.sealed.classes;
+
+public abstract sealed class Vehicle permits Car, Truck {
+
+    protected final String registrationNumber;
+
+    public Vehicle(String registrationNumber) {
+        this.registrationNumber = registrationNumber;
+    }
+
+    public String getRegistrationNumber() {
+        return registrationNumber;
+    }
+
+}

core-java-modules/core-java-15/src/main/java/com/baeldung/sealed/records/Car.java

@@ -0,0 +1,14 @@
+package com.baeldung.sealed.records;
+
+public record Car(int numberOfSeats, String registrationNumber) implements Vehicle {
+
+    @Override
+    public String getRegistrationNumber() {
+        return registrationNumber;
+    }
+
+    public int getNumberOfSeats() {
+        return numberOfSeats;
+    }
+
+}

core-java-modules/core-java-15/src/main/java/com/baeldung/sealed/records/Truck.java

@@ -0,0 +1,14 @@
+package com.baeldung.sealed.records;
+
+public record Truck(int loadCapacity, String registrationNumber) implements Vehicle {
+
+    @Override
+    public String getRegistrationNumber() {
+        return registrationNumber;
+    }
+
+    public int getLoadCapacity() {
+        return loadCapacity;
+    }
+
+}

core-java-modules/core-java-15/src/main/java/com/baeldung/sealed/records/Vehicle.java

@@ -0,0 +1,7 @@
+package com.baeldung.sealed.records;
+
+public sealed interface Vehicle permits Car, Truck {
+
+    String getRegistrationNumber();
+
+}

core-java-modules/core-java-15/src/main/java/com/baeldung/whatsnew/records/Person.java

@@ -0,0 +1,15 @@
+package com.baeldung.whatsnew.records;
+
+/**
+ * Java record with a header indicating 2 fields.
+ */
+public record Person(String name, int age) {
+    /**
+     * Public constructor that does some basic validation.
+     */
+    public Person {
+        if (age < 0) {
+            throw new IllegalArgumentException("Age cannot be negative");
+        }
+    }
+}

core-java-modules/core-java-15/src/main/java/com/baeldung/whatsnew/sealedclasses/Employee.java

@@ -0,0 +1,9 @@
+package com.baeldung.whatsnew.sealedclasses;
+
+import java.util.Date;
+
+public non-sealed class Employee extends Person {
+    public Date getHiredDate() {
+        return new Date();
+    }
+}

core-java-modules/core-java-15/src/main/java/com/baeldung/whatsnew/sealedclasses/Manager.java

@@ -0,0 +1,4 @@
+package com.baeldung.whatsnew.sealedclasses;
+
+public final class Manager extends Person {
+}