Merge branch 'eugenp:master' into master

core-java-modules/core-java-16/pom.xml

@@ -63,4 +63,4 @@
         <surefire.plugin.version>3.0.0-M5</surefire.plugin.version>
     </properties>
 
-</project>
+</project>

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/enumallt/DinosaurEnum.java

@@ -0,0 +1,19 @@
+package com.baeldung.instanceofalternative.enumallt;
+
+public enum DinosaurEnum {
+    Anatotitan {
+        @Override
+        public String move() {
+            return "running";
+        }
+    },
+    Euraptor {
+        @Override
+        public String move() {
+            return "flying";
+        }
+    };
+
+    public abstract String move();
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/model/Anatotitan.java

@@ -0,0 +1,15 @@
+package com.baeldung.instanceofalternative.model;
+
+public class Anatotitan extends Dinosaur {
+    // polymorphism
+    @Override
+    public String move() {
+        return "running";
+    }
+
+    // non-polymorphism
+    public String run() {
+        return "running";
+    }
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/model/Dinosaur.java

@@ -0,0 +1,9 @@
+package com.baeldung.instanceofalternative.model;
+
+public class Dinosaur {
+
+    public String move() {
+        return "default movement";
+    }
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/model/Euraptor.java

@@ -0,0 +1,15 @@
+package com.baeldung.instanceofalternative.model;
+
+public class Euraptor extends Dinosaur {
+    // polymorphism
+    @Override
+    public String move() {
+        return "flying";
+    }
+
+    // non-polymorphism
+    public String flies() {
+        return "flying";
+    }
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/visitorspattern/Anatotitan.java

@@ -0,0 +1,14 @@
+package com.baeldung.instanceofalternative.visitorspattern;
+
+public class Anatotitan implements Dino {
+
+    String run() {
+        return "running";
+    }
+
+    @Override
+    public String move(Visitor dinobehave) {
+        return dinobehave.visit(this);
+    }
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/visitorspattern/Dino.java

@@ -0,0 +1,7 @@
+package com.baeldung.instanceofalternative.visitorspattern;
+
+public interface Dino {
+
+    String move(Visitor dinoMove);
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/visitorspattern/DinoVisitorImpl.java

@@ -0,0 +1,15 @@
+package com.baeldung.instanceofalternative.visitorspattern;
+
+public class DinoVisitorImpl implements Visitor {
+
+    @Override
+    public String visit(Anatotitan anatotitan) {
+        return anatotitan.run();
+    }
+
+    @Override
+    public String visit(Euraptor euraptor) {
+        return euraptor.flies();
+    }
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/visitorspattern/Euraptor.java

@@ -0,0 +1,14 @@
+package com.baeldung.instanceofalternative.visitorspattern;
+
+public class Euraptor implements Dino {
+
+    String flies() {
+        return "flying";
+    }
+
+    @Override
+    public String move(Visitor dinobehave) {
+        return dinobehave.visit(this);
+    }
+
+}

core-java-modules/core-java-16/src/main/java/com/baeldung/instanceof_alternatives/visitorspattern/Visitor.java

@@ -0,0 +1,9 @@
+package com.baeldung.instanceofalternative.visitorspattern;
+
+public interface Visitor {
+
+    String visit(Anatotitan anatotitan);
+
+    String visit(Euraptor euraptor);
+
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/instanceof_alternative_test/EnumUnitTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.instanceoftest;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import com.baeldung.instanceofalternative.enumallt.*;
+
+public class EnumUnitTest {
+    @Test
+    public void givenADinosaurSpecie_whenUsingEnum_thenGetMovementOfEuraptor() {
+
+        assertEquals("flying", moveDinosaurUsingEnum(DinosaurEnum.Euraptor));
+    }
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingEnum_thenGetMovementOfAnatotitan() {
+        assertEquals("running", moveDinosaurUsingEnum(DinosaurEnum.Anatotitan));
+    }
+
+    public static String moveDinosaurUsingEnum(DinosaurEnum dinosaurenum) {
+        return dinosaurenum.move();
+
+    }
+
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/instanceof_alternative_test/ExampleSetupUnitTest.java

@@ -0,0 +1,35 @@
+package com.baeldung.instanceoftest;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import com.baeldung.instanceofalternative.model.*;
+
+public class ExampleSetupUnitTest {
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingInstancof_thenGetMovementOfAnatotitan() {
+
+        assertEquals("running", moveDinosaurUsingInstanceof(new Anatotitan()));
+    }
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingInstanceof_thenGetMovementOfEuraptor() {
+        assertEquals("flying", moveDinosaurUsingInstanceof(new Euraptor()));
+    }
+
+    public static String moveDinosaurUsingInstanceof(Dinosaur dinosaur) {
+
+        if (dinosaur instanceof Anatotitan) {
+
+            Anatotitan anatotitan = (Anatotitan) dinosaur;
+            return anatotitan.run();
+        } else if (dinosaur instanceof Euraptor) {
+            Euraptor euraptor = (Euraptor) dinosaur;
+            return euraptor.flies();
+        }
+        return "";
+    }
+
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/instanceof_alternative_test/GetClassUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.instanceoftest;
+
+import static org.junit.Assert.*;
+import org.junit.Test;
+
+import com.baeldung.instanceofalternative.model.*;
+
+public class GetClassUnitTest {
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingGetClass_thenGetMovementOfAnatotitan() {
+
+        assertEquals("running", moveDinosaurUsingGetClass(new Anatotitan()));
+    }
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingGetClass_thenGetMovementOfEuraptor() {
+        assertEquals("flying", moveDinosaurUsingGetClass(new Euraptor()));
+    }
+
+    public static String moveDinosaurUsingGetClass(Dinosaur dinosaur) {
+
+        if (dinosaur.getClass()
+            .equals(Anatotitan.class)) {
+
+            Anatotitan anatotitan = (Anatotitan) dinosaur;
+            return anatotitan.run();
+        } else if (dinosaur.getClass()
+            .equals(Euraptor.class)) {
+            Euraptor euraptor = (Euraptor) dinosaur;
+            return euraptor.flies();
+        }
+        return "";
+    }
+
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/instanceof_alternative_test/PolymorphismUnitTest.java

@@ -0,0 +1,27 @@
+package com.baeldung.instanceoftest;
+
+import static org.junit.Assert.*;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import com.baeldung.instanceofalternative.model.*;
+
+public class PolymorphismUnitTest {
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingPolymorphism_thenGetMovementOfAnatotitan() {
+
+        assertEquals("running", moveDinosaurUsingPolymorphism(new Anatotitan()));
+    }
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingPolymorphism_thenGetMovementOfEuraptor() {
+        assertEquals("flying", moveDinosaurUsingPolymorphism(new Euraptor()));
+    }
+
+    public static String moveDinosaurUsingPolymorphism(Dinosaur dinosaur) {
+        return dinosaur.move();
+    }
+
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/instanceof_alternative_test/VisitorsPatternUnitTest.java

@@ -0,0 +1,29 @@
+package com.baeldung.instanceoftest;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import com.baeldung.instanceofalternative.visitorspattern.*;
+
+public class VisitorsPatternUnitTest {
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingVisitorPattern_thenGetMovementOfAnatotitan() {
+
+        assertEquals("running", moveDinosaurUsingVisitorPattern((Dino) new Anatotitan()));
+    }
+
+    @Test
+    public void givenADinosaurSpecie_whenUsingVisitorPattern_thenGetMovementOfEuraptor() {
+
+        assertEquals("flying", moveDinosaurUsingVisitorPattern((Dino) new Euraptor()));
+    }
+
+    public static String moveDinosaurUsingVisitorPattern(Dino dinosaur) {
+        Visitor visitor = new DinoVisitorImpl();
+
+        return dinosaur.move(visitor);
+    }
+
+}

core-java-modules/core-java-exceptions-4/src/main/java/com/baeldung/exception/exceptions_vs_errors/ErrorExample.java

@@ -1,14 +1,9 @@
 package com.baeldung.exception.exceptions_vs_errors;
 
 public class ErrorExample {
-    
-    public static void main(String[] args) {
-        overflow();
-    }
 
-    public static void overflow() {
-        System.out.println("overflow...");
-        overflow();
+    public static void main(String[] args) {
+        throw new AssertionError();
     }
 
 }

core-java-modules/core-java-exceptions-4/src/test/java/com/baeldung/exception/exceptions_vs_errors/ErrorExampleUnitTest.java

@@ -3,11 +3,11 @@ package com.baeldung.exception.exceptions_vs_errors;
 import org.junit.Test;
 import org.junit.jupiter.api.Assertions;
 
-// Unit test for the ErrorExample class.
 public class ErrorExampleUnitTest {
+
     @Test
     public void whenMainMethodIsRun_thenStackOverflowError() {
-        Assertions.assertThrows(StackOverflowError.class, 
-            () -> ErrorExample.main(null));
+        Assertions.assertThrows(AssertionError.class,
+          () -> ErrorExample.main(null));
     }
 }

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

@@ -14,5 +14,4 @@ This module contains articles about working with the Java Virtual Machine (JVM).
 - [An Introduction to the Constant Pool in the JVM](https://www.baeldung.com/jvm-constant-pool)
 - [List All the Classes Loaded in the JVM](https://www.baeldung.com/jvm-list-all-classes-loaded)
 - [Static Fields and Garbage Collection](https://www.baeldung.com/java-static-fields-gc)
-- [Difference Between Class.getResource() and ClassLoader.getResource()](https://www.baeldung.com/java-class-vs-classloader-getresource)
-- More articles: [[<-- prev]](/core-java-modules/core-java-jvm)
+- More articles: [[<-- prev]](/core-java-modules/core-java-jvm) [[next -->]](/core-java-modules/core-java-jvm-3)

core-java-modules/core-java-jvm-3/README.md

@@ -0,0 +1,8 @@
+## Core Java JVM Cookbooks and Examples
+
+This module contains articles about working with the Java Virtual Machine (JVM).
+
+### Relevant Articles: 
+
+- [Difference Between Class.getResource() and ClassLoader.getResource()](https://www.baeldung.com/java-class-vs-classloader-getresource)
+- More articles: [[<-- prev]](/core-java-modules/core-java-jvm-2)

core-java-modules/core-java-jvm-3/pom.xml

@@ -0,0 +1,21 @@
+<?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-jvm-3</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-jvm-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>
+
+    <dependencies>
+    
+    </dependencies>
+
+</project>

core-java-modules/core-java-lambdas/src/main/java/com/baeldung/anonymousclass/EmailSenderService.java

@@ -0,0 +1,10 @@
+package com.baeldung.anonymousclass;
+
+public class EmailSenderService implements SenderService {
+
+    @Override
+    public String callSender(Sender sender) {
+        return sender.send("Email Notification");
+    }
+
+}

core-java-modules/core-java-lambdas/src/main/java/com/baeldung/anonymousclass/Sender.java

@@ -0,0 +1,7 @@
+package com.baeldung.anonymousclass;
+
+public interface Sender {
+
+    String send(final String message);
+
+}

core-java-modules/core-java-lambdas/src/main/java/com/baeldung/anonymousclass/SenderService.java

@@ -0,0 +1,7 @@
+package com.baeldung.anonymousclass;
+
+public interface SenderService {
+
+    String callSender(Sender sender);
+
+}

core-java-modules/core-java-lambdas/src/main/java/com/baeldung/anonymousclass/SmsSenderService.java

@@ -0,0 +1,10 @@
+package com.baeldung.anonymousclass;
+
+public class SmsSenderService implements SenderService {
+
+    @Override
+    public String callSender(Sender sender) {
+        return sender.send("SMS Notification");
+    }
+
+}

core-java-modules/core-java-lambdas/src/test/java/com/baeldung/anonymousclass/AnonymousClassToLambdaIntegrationTest.java

@@ -0,0 +1,34 @@
+package com.baeldung.anonymousclass;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class AnonymousClassToLambdaIntegrationTest {
+
+    @Test
+    public void whenPassingAnonymousClass_thenSuccess() {
+        final SenderService emailSenderService = new EmailSenderService();
+
+        final String emailNotif = emailSenderService.callSender(new Sender() {
+            @Override
+            public String send(String message) {
+                return message;
+            }
+        });
+
+        assertEquals(emailNotif, "Email Notification");
+    }
+
+    @Test
+    public void whenPassingLambdaExpression_thenSuccess() {
+        final SenderService smsSenderService = new SmsSenderService();
+
+        final String smsNotif = smsSenderService.callSender((String message) -> {
+            return message;
+        });
+
+        assertEquals(smsNotif, "SMS Notification");
+    }
+
+}