Merge pull request #8249 from catalin-burcea/BAEL-16531

[BAEL-16531] - Move all the existing articles on "optional" under jav…

core-java-modules/core-java-11/README.md

@@ -12,4 +12,3 @@ This module contains articles about Java 11 core features
 - [An Introduction to Epsilon GC: A No-Op Experimental Garbage Collector](https://www.baeldung.com/jvm-epsilon-gc-garbage-collector)
 - [Guide to jlink](https://www.baeldung.com/jlink)
 - [Negate a Predicate Method Reference with Java 11](https://www.baeldung.com/java-negate-predicate-method-reference)
-- [Transforming an Empty String into an Empty Optional](https://www.baeldung.com/java-empty-string-to-empty-optional)

core-java-modules/core-java-8-2/src/main/resources/META-INF/persistence.xml

@@ -5,14 +5,14 @@
 	version="2.0">
 
 	<persistence-unit
-		name="com.baeldung.optionalReturnType"
+		name="com.baeldung.optionalreturntype"
 		transaction-type="RESOURCE_LOCAL">
 		<description>Persist Optional Return Type Demo</description>
 		<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
-		<class>com.baeldung.optionalReturnType.User</class>
-		<class>com.baeldung.optionalReturnType.UserOptional</class>
+		<class>com.baeldung.optionalreturntype.User</class>
+		<class>com.baeldung.optionalreturntype.UserOptional</class>
 		<!-- 
-		<class>com.baeldung.optionalReturnType.UserOptionalField</class>
+		<class>com.baeldung.optionalreturntype.UserOptionalField</class>
 		-->
 		<exclude-unlisted-classes>true</exclude-unlisted-classes>
 

core-java-modules/core-java-9-improvements/README.md

@@ -5,7 +5,6 @@ This module contains articles about the improvements to core Java features intro
 ### Relevant Articles:
 
 - [New Stream Collectors in Java 9](http://www.baeldung.com/java9-stream-collectors)
-- [Java 9 Optional API Additions](https://www.baeldung.com/java-9-optional)
 - [Java 9 Convenience Factory Methods for Collections](https://www.baeldung.com/java-9-collections-factory-methods)
 - [Java 9 Stream API Improvements](https://www.baeldung.com/java-9-stream-api)
 - [Java 9 java.util.Objects Additions](https://www.baeldung.com/java-9-objects-new)

core-java-modules/core-java-9-improvements/src/test/java/com/baeldung/java9/Java9OptionalTest.java

@@ -1,85 +0,0 @@
-package com.baeldung.java9;
-
-public class Java9OptionalTest {
-    @Test
-    public void givenOptionalOfSome_whenToStream_thenShouldTreatItAsOneElementStream() {
-        //given
-        Optional<String> value = Optional.of("a");
-
-        //when
-        List<String> collect = value.stream().map(String::toUpperCase).collect(Collectors.toList());
-
-        //then
-        assertThat(collect).hasSameElementsAs(List.of("A"));
-    }
-
-    @Test
-    public void givenOptionalOfNone_whenToStream_thenShouldTreatItAsZeroElementStream() {
-        //given
-        Optional<String> value = Optional.empty();
-
-        //when
-        List<String> collect = value.stream().map(String::toUpperCase).collect(Collectors.toList());
-
-        //then
-        assertThat(collect).isEmpty();
-    }
-
-    @Test
-    public void givenOptional_whenPresent_thenShouldExecuteProperCallback() {
-        //given
-        Optional<String> value = Optional.of("properValue");
-        AtomicInteger successCounter = new AtomicInteger(0);
-        AtomicInteger onEmptyOptionalCounter = new AtomicInteger(0);
-
-        //when
-        value.ifPresentOrElse((v) -> successCounter.incrementAndGet(), onEmptyOptionalCounter::incrementAndGet);
-
-        //then
-        assertThat(successCounter.get()).isEqualTo(1);
-        assertThat(onEmptyOptionalCounter.get()).isEqualTo(0);
-    }
-
-    @Test
-    public void givenOptional_whenNotPresent_thenShouldExecuteProperCallback() {
-        //given
-        Optional<String> value = Optional.empty();
-        AtomicInteger successCounter = new AtomicInteger(0);
-        AtomicInteger onEmptyOptionalCounter = new AtomicInteger(0);
-
-        //when
-        value.ifPresentOrElse((v) -> successCounter.incrementAndGet(), onEmptyOptionalCounter::incrementAndGet);
-
-        //then
-        assertThat(successCounter.get()).isEqualTo(0);
-        assertThat(onEmptyOptionalCounter.get()).isEqualTo(1);
-    }
-
-    @Test
-    public void givenOptional_whenPresent_thenShouldTakeAValueFromIt() {
-        //given
-        String expected = "properValue";
-        Optional<String> value = Optional.of(expected);
-        Optional<String> defaultValue = Optional.of("default");
-
-        //when
-        Optional<String> result = value.or(() -> defaultValue);
-
-        //then
-        assertThat(result.get()).isEqualTo(expected);
-    }
-
-    @Test
-    public void givenOptional_whenEmpty_thenShouldTakeAValueFromOr() {
-        //given
-        String defaultString = "default";
-        Optional<String> value = Optional.empty();
-        Optional<String> defaultValue = Optional.of(defaultString);
-
-        //when
-        Optional<String> result = value.or(() -> defaultValue);
-
-        //then
-        assertThat(result.get()).isEqualTo(defaultString);
-    }
-}

core-java-modules/core-java-9/README.md

@@ -4,13 +4,11 @@ This module contains articles about Java 9 core features
 
 ### Relevant Articles:
 
-- [Method Handles in Java](http://www.baeldung.com/java-method-handles)
-- [Introduction to Chronicle Queue](http://www.baeldung.com/java-chronicle-queue)
-- [Optional orElse Optional](http://www.baeldung.com/java-optional-or-else-optional)
+- [Method Handles in Java](https://www.baeldung.com/java-method-handles)
+- [Introduction to Chronicle Queue](https://www.baeldung.com/java-chronicle-queue)
 - [Iterate Through a Range of Dates in Java](https://www.baeldung.com/java-iterate-date-range)
 - [Initialize a HashMap in Java](https://www.baeldung.com/java-initialize-hashmap)
 - [Immutable Set in Java](https://www.baeldung.com/java-immutable-set)
-- [Filtering a Stream of Optionals in Java](https://www.baeldung.com/java-filter-stream-of-optional)
 
 Note: also contains part of the code for the article
 [How to Filter a Collection in Java](https://www.baeldung.com/java-collection-filtering).

core-java-modules/core-java-9/src/test/java/com/baeldung/optionals/OptionalsTest.java

@@ -1,51 +0,0 @@
-package com.baeldung.optionals;
-
-import static org.junit.Assert.assertEquals;
-
-import java.util.Optional;
-
-import org.junit.Test;
-
-public class OptionalsTest {
-
-    @Test
-    public void givenOptional_whenEmptyValue_thenCustomMessage() {
-        assertEquals(Optional.of("Name not provided"), Optionals.getName(Optional.ofNullable(null)));
-    }
-
-    @Test
-    public void givenOptional_whenValue_thenOptional() {
-        String name = "Filan Fisteku";
-        Optional<String> optionalString = Optional.ofNullable(name);
-        assertEquals(optionalString, Optionals.getName(optionalString));
-    }
-    
-    @Test
-    public void givenOptional_whenValue_thenOptionalGeneralMethod() {
-        String name = "Filan Fisteku";
-        String missingOptional = "Name not provided";
-        Optional<String> optionalString = Optional.ofNullable(name);
-        Optional<String> fallbackOptionalString = Optional.ofNullable(missingOptional);
-        assertEquals(optionalString, Optionals.or(optionalString, fallbackOptionalString));
-    }
-    
-    @Test
-    public void givenEmptyOptional_whenValue_thenOptionalGeneralMethod() {
-        String missingOptional = "Name not provided";
-        Optional<String> optionalString = Optional.empty();
-        Optional<String> fallbackOptionalString = Optional.ofNullable(missingOptional);
-        assertEquals(fallbackOptionalString, Optionals.or(optionalString, fallbackOptionalString));
-    }
-
-    @Test
-    public void givenGuavaOptional_whenInvoke_thenOptional() {
-        String name = "Filan Fisteku";
-        com.google.common.base.Optional<String> stringOptional = com.google.common.base.Optional.of(name);
-        assertEquals(stringOptional, Optionals.getOptionalGuavaName(stringOptional));
-    }
-
-    @Test
-    public void givenGuavaOptional_whenNull_thenDefaultText() {
-        assertEquals(com.google.common.base.Optional.of("Name not provided"), Optionals.getOptionalGuavaName(com.google.common.base.Optional.fromNullable(null)));
-    }
-} 

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

@@ -15,6 +15,5 @@ This module contains articles about core java exceptions
 - [Java – Try with Resources](https://www.baeldung.com/java-try-with-resources)
 - [Java Global Exception Handler](https://www.baeldung.com/java-global-exception-handler)
 - [Common Java Exceptions](https://www.baeldung.com/java-common-exceptions)
-- [Throw Exception in Optional in Java 8](https://www.baeldung.com/java-optional-throw-exception)
 - [How to Find an Exception’s Root Cause in Java](https://www.baeldung.com/java-exception-root-cause)
 - [Is It a Bad Practice to Catch Throwable?](https://www.baeldung.com/java-catch-throwable-bad-practice)

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

@@ -1,8 +1,13 @@
-=========
+## Java Optional
 
-## Core Java Optional
+This module contains articles about Java Optional.
 
 ### Relevant Articles: 
 - [Java Optional as Return Type](https://www.baeldung.com/java-optional-return)
-- [Guide To Java 8 Optional](https://www.baeldung.com/java-optional)
+- [Guide to Java 8 Optional](https://www.baeldung.com/java-optional)
 - [Java Optional – orElse() vs orElseGet()](https://www.baeldung.com/java-optional-or-else-vs-or-else-get)
+- [Transforming an Empty String into an Empty Optional](https://www.baeldung.com/java-empty-string-to-empty-optional)
+- [Filtering a Stream of Optionals in Java](https://www.baeldung.com/java-filter-stream-of-optional)
+- [Java 9 Optional API Additions](https://www.baeldung.com/java-9-optional)
+- [Throw Exception in Optional in Java 8](https://www.baeldung.com/java-optional-throw-exception)
+- [Optional orElse Optional](https://www.baeldung.com/java-optional-or-else-optional)

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

@@ -42,11 +42,31 @@
             <artifactId>jmh-generator-bytecode</artifactId>
             <version>${jmh-generator.version}</version>
         </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.rest-assured</groupId>
+            <artifactId>json-path</artifactId>
+            <version>${rest-assured.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <properties>
         <hibernate.core.version>5.4.0.Final</hibernate.core.version>
         <jmh-core.version>1.19</jmh-core.version>
         <jmh-generator.version>1.19</jmh-generator.version>
+        <guava.version>27.1-jre</guava.version>
+        <assertj.version>3.10.0</assertj.version>
+        <rest-assured.version>3.1.1</rest-assured.version>
     </properties>
 </project>

core-java-modules/core-java-optional/src/main/java/com/baeldung/optional/orelse/OrElseAndOrElseGet.java

@@ -1,4 +1,4 @@
-package com.baeldung.optional;
+package com.baeldung.optional.orelse;
 
 import java.util.Arrays;
 import java.util.List;

core-java-modules/core-java-optional/src/main/java/com/baeldung/optional/orelse/OrElseAndOrElseGetBenchmarkRunner.java

@@ -1,4 +1,4 @@
-package com.baeldung.optional;
+package com.baeldung.optional.orelse;
 
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;

core-java-modules/core-java-optional/src/main/java/com/baeldung/optionalreturntype/HandleOptionalTypeExample.java

@@ -1,4 +1,4 @@
-package com.baeldung.optionalReturnType;
+package com.baeldung.optionalreturntype;
 
 import java.util.HashMap;
 import java.util.Map;

core-java-modules/core-java-optional/src/main/java/com/baeldung/optionalreturntype/OptionalToJsonExample.java

@@ -1,4 +1,4 @@
-package com.baeldung.optionalReturnType;
+package com.baeldung.optionalreturntype;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;

core-java-modules/core-java-optional/src/main/java/com/baeldung/optionalreturntype/PersistOptionalTypeExample.java

@@ -1,4 +1,4 @@
-package com.baeldung.optionalReturnType;
+package com.baeldung.optionalreturntype;
 
 import java.util.Optional;
 
@@ -7,13 +7,13 @@ import javax.persistence.EntityManagerFactory;
 import javax.persistence.Persistence;
 
 public class PersistOptionalTypeExample {
-    static String persistenceUnit = "com.baeldung.optionalReturnType";
+    static String persistenceUnit = "com.baeldung.optionalreturntype";
     static EntityManagerFactory emf = Persistence.createEntityManagerFactory(persistenceUnit);
 
     static EntityManager entityManager = emf.createEntityManager();
 
     // to run this app, uncomment the follow line in META-INF/persistence.xml
-    // <class>com.baeldung.optionalReturnType.UserOptionalField</class>
+    // <class>com.baeldung.optionalreturntype.UserOptionalField</class>
     public static void main(String[] args) {
         UserOptionalField user1 = new UserOptionalField();
         user1.setUserId(1l);

core-java-modules/core-java-optional/src/main/java/com/baeldung/optionalreturntype/PersistOptionalTypeExample2.java

@@ -1,11 +1,11 @@
-package com.baeldung.optionalReturnType;
+package com.baeldung.optionalreturntype;
 
 import javax.persistence.EntityManager;
 import javax.persistence.EntityManagerFactory;
 import javax.persistence.Persistence;
 
 public class PersistOptionalTypeExample2 {
-    static String persistenceUnit = "com.baeldung.optionalReturnType";
+    static String persistenceUnit = "com.baeldung.optionalreturntype";
     static EntityManagerFactory emf = Persistence.createEntityManagerFactory(persistenceUnit);
 
     static EntityManager em = emf.createEntityManager();

core-java-modules/core-java-optional/src/main/java/com/baeldung/optionalreturntype/PersistUserExample.java

@@ -1,11 +1,11 @@
-package com.baeldung.optionalReturnType;
+package com.baeldung.optionalreturntype;
 
 import javax.persistence.EntityManager;
 import javax.persistence.EntityManagerFactory;
 import javax.persistence.Persistence;
 
 public class PersistUserExample {
-    static String persistenceUnit = "com.baeldung.optionalReturnType";
+    static String persistenceUnit = "com.baeldung.optionalreturntype";
     static EntityManagerFactory emf = Persistence.createEntityManagerFactory(persistenceUnit);
 
     static EntityManager em = emf.createEntityManager();

core-java-modules/core-java-optional/src/main/java/com/baeldung/optionalreturntype/SerializeOptionalTypeExample.java

@@ -1,4 +1,4 @@
-package com.baeldung.optionalReturnType;
+package com.baeldung.optionalreturntype;
 
 import java.io.FileOutputStream;
 import java.io.IOException;

core-java-modules/core-java-optional/src/main/java/com/baeldung/optionalreturntype/User.java

@@ -1,4 +1,4 @@
-package com.baeldung.optionalReturnType;
+package com.baeldung.optionalreturntype;
 
 import java.io.Serializable;
 

core-java-modules/core-java-optional/src/main/java/com/baeldung/optionalreturntype/UserOptional.java

@@ -1,4 +1,4 @@
-package com.baeldung.optionalReturnType;
+package com.baeldung.optionalreturntype;
 
 import java.io.Serializable;
 import java.util.Optional;

core-java-modules/core-java-optional/src/main/java/com/baeldung/optionalreturntype/UserOptionalField.java

@@ -1,4 +1,4 @@
-package com.baeldung.optionalReturnType;
+package com.baeldung.optionalreturntype;
 
 import java.io.Serializable;
 import java.util.Optional;

core-java-modules/core-java-optional/src/main/java/com/baeldung/orelseoptional/OptionalUtils.java

@@ -1,20 +1,20 @@
-package com.baeldung.optionals;
+package com.baeldung.orelseoptional;
 
 import java.util.Optional;
 
-public class Optionals {
+public class OptionalUtils {
 
     public static <T> Optional<T> or(Optional<T> optional, Optional<T> fallback) {
         return optional.isPresent() ? optional : fallback;
     }
 
-    public static Optional<String> getName(Optional<String> name) {
-        return name.or(() -> getCustomMessage());
-    }
-
-    public static com.google.common.base.Optional<String> getOptionalGuavaName(com.google.common.base.Optional<String> name) {
-        return name.or(getCustomMessageGuava());
-    }
+//    public static Optional<String> getName(Optional<String> name) {
+//        return name.or(() -> getCustomMessage());
+//    }
+//
+//    public static com.google.common.base.Optional<String> getOptionalGuavaName(com.google.common.base.Optional<String> name) {
+//        return name.or(getCustomMessageGuava());
+//    }
 
     private static Optional<String> getCustomMessage() {
         return Optional.of("Name not provided");

core-java-modules/core-java-optional/src/test/java/com/baeldung/emptystringoptional/EmptyStringToEmptyOptionalUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.emptystringoptional;
 
 import com.google.common.base.Strings;
 import org.junit.Assert;
@@ -16,12 +16,13 @@ public class EmptyStringToEmptyOptionalUnitTest {
         Assert.assertFalse(opt.isPresent());
     }
 
-    @Test
-    public void givenEmptyString_whenFilteringOnOptionalInJava11_thenEmptyOptionalIsReturned() {
-        String str = "";
-        Optional<String> opt = Optional.ofNullable(str).filter(Predicate.not(String::isEmpty));
-        Assert.assertFalse(opt.isPresent());
-    }
+//    Uncomment code when code base is compatible with Java 11
+//    @Test
+//    public void givenEmptyString_whenFilteringOnOptionalInJava11_thenEmptyOptionalIsReturned() {
+//        String str = "";
+//        Optional<String> opt = Optional.ofNullable(str).filter(Predicate.not(String::isEmpty));
+//        Assert.assertFalse(opt.isPresent());
+//    }
 
     @Test
     public void givenEmptyString_whenPassingResultOfEmptyToNullToOfNullable_thenEmptyOptionalIsReturned() {

core-java-modules/core-java-optional/src/test/java/com/baeldung/filterstream/Java9OptionalsStreamUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.java9;
+package com.baeldung.filterstream;
 
 import static org.junit.Assert.assertEquals;
 
@@ -47,15 +47,17 @@ public class Java9OptionalsStreamUnitTest {
         assertEquals("bar", filteredList.get(1));
     }
 
-    @Test
-    public void filterOutPresentOptionalsWithJava9() {
-        assertEquals(4, listOfOptionals.size());
 
-        List<String> filteredList = listOfOptionals.stream().flatMap(Optional::stream).collect(Collectors.toList());
-
-        assertEquals(2, filteredList.size());
-        assertEquals("foo", filteredList.get(0));
-        assertEquals("bar", filteredList.get(1));
-    }
+//    Uncomment code when code base is compatible with Java 9
+//    @Test
+//    public void filterOutPresentOptionalsWithJava9() {
+//        assertEquals(4, listOfOptionals.size());
+//
+//        List<String> filteredList = listOfOptionals.stream().flatMap(Optional::stream).collect(Collectors.toList());
+//
+//        assertEquals(2, filteredList.size());
+//        assertEquals("foo", filteredList.get(0));
+//        assertEquals("bar", filteredList.get(1));
+//    }
 
 }

core-java-modules/core-java-optional/src/test/java/com/baeldung/java9additions/Java9OptionalUnitTest.java

@@ -0,0 +1,95 @@
+package com.baeldung.java9additions;
+
+import org.junit.Test;
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.stream.Collectors;
+
+//    Uncomment code when code base is compatible with Java 9
+//public class Java9OptionalUnitTest {
+//
+//    @Test
+//    public void givenOptionalOfSome_whenToStream_thenShouldTreatItAsOneElementStream() {
+//        //given
+//        Optional<String> value = Optional.of("a");
+//
+//        //when
+//        List<String> collect = value.stream().map(String::toUpperCase).collect(Collectors.toList());
+//
+//        //then
+//        assertThat(collect).hasSameElementsAs(List.of("A"));
+//    }
+//
+//    @Test
+//    public void givenOptionalOfNone_whenToStream_thenShouldTreatItAsZeroElementStream() {
+//        //given
+//        Optional<String> value = Optional.empty();
+//
+//        //when
+//        List<String> collect = value.stream().map(String::toUpperCase).collect(Collectors.toList());
+//
+//        //then
+//        assertThat(collect).isEmpty();
+//    }
+//
+//    @Test
+//    public void givenOptional_whenPresent_thenShouldExecuteProperCallback() {
+//        //given
+//        Optional<String> value = Optional.of("properValue");
+//        AtomicInteger successCounter = new AtomicInteger(0);
+//        AtomicInteger onEmptyOptionalCounter = new AtomicInteger(0);
+//
+//        //when
+//        value.ifPresentOrElse((v) -> successCounter.incrementAndGet(), onEmptyOptionalCounter::incrementAndGet);
+//
+//        //then
+//        assertThat(successCounter.get()).isEqualTo(1);
+//        assertThat(onEmptyOptionalCounter.get()).isEqualTo(0);
+//    }
+//
+//    @Test
+//    public void givenOptional_whenNotPresent_thenShouldExecuteProperCallback() {
+//        //given
+//        Optional<String> value = Optional.empty();
+//        AtomicInteger successCounter = new AtomicInteger(0);
+//        AtomicInteger onEmptyOptionalCounter = new AtomicInteger(0);
+//
+//        //when
+//        value.ifPresentOrElse((v) -> successCounter.incrementAndGet(), onEmptyOptionalCounter::incrementAndGet);
+//
+//        //then
+//        assertThat(successCounter.get()).isEqualTo(0);
+//        assertThat(onEmptyOptionalCounter.get()).isEqualTo(1);
+//    }
+//
+//    @Test
+//    public void givenOptional_whenPresent_thenShouldTakeAValueFromIt() {
+//        //given
+//        String expected = "properValue";
+//        Optional<String> value = Optional.of(expected);
+//        Optional<String> defaultValue = Optional.of("default");
+//
+//        //when
+//        Optional<String> result = value.or(() -> defaultValue);
+//
+//        //then
+//        assertThat(result.get()).isEqualTo(expected);
+//    }
+//
+//    @Test
+//    public void givenOptional_whenEmpty_thenShouldTakeAValueFromOr() {
+//        //given
+//        String defaultString = "default";
+//        Optional<String> value = Optional.empty();
+//        Optional<String> defaultValue = Optional.of(defaultString);
+//
+//        //when
+//        Optional<String> result = value.or(() -> defaultValue);
+//
+//        //then
+//        assertThat(result.get()).isEqualTo(defaultString);
+//    }
+//}

core-java-modules/core-java-optional/src/test/java/com/baeldung/optional/OptionalChainingUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.java8.optional;
+package com.baeldung.optional;
 
 import org.junit.Before;
 import org.junit.Test;

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

@@ -1,7 +1,5 @@
-package com.baeldung.java8.optional;
+package com.baeldung.optional;
 
-import com.baeldung.optional.Modem;
-import com.baeldung.optional.Person;
 import org.junit.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -260,7 +258,7 @@ public class OptionalUnitTest {
         return "Default Value";
     }
     
-//    Uncomment code when code base is compatiable with Java 11     
+//    Uncomment code when code base is compatible with Java 11
 //    @Test
 //    public void givenAnEmptyOptional_thenIsEmptyBehavesAsExpected() {
 //        Optional<String> opt = Optional.of("Baeldung");

core-java-modules/core-java-optional/src/test/java/com/baeldung/optional/orelse/OrElseAndOrElseGetUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.java8.optional;
+package com.baeldung.optional.orelse;
 
 import org.junit.Test;
 import org.slf4j.Logger;
@@ -6,8 +6,6 @@ import org.slf4j.LoggerFactory;
 
 import static org.junit.Assert.*;
 
-import com.baeldung.optional.OrElseAndOrElseGet;
-
 public class OrElseAndOrElseGetUnitTest {
 
     private OrElseAndOrElseGet orElsevsOrElseGet = new OrElseAndOrElseGet();

core-java-modules/core-java-optional/src/test/java/com/baeldung/orelseoptional/OrElseOptionalUnitTest.java

@@ -0,0 +1,52 @@
+package com.baeldung.orelseoptional;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Optional;
+
+import org.junit.Test;
+
+public class OrElseOptionalUnitTest {
+
+    @Test
+    public void givenOptional_whenValue_thenOptionalGeneralMethod() {
+        String name = "Filan Fisteku";
+        String missingOptional = "Name not provided";
+        Optional<String> optionalString = Optional.ofNullable(name);
+        Optional<String> fallbackOptionalString = Optional.ofNullable(missingOptional);
+        assertEquals(optionalString, OptionalUtils.or(optionalString, fallbackOptionalString));
+    }
+
+    @Test
+    public void givenEmptyOptional_whenValue_thenOptionalGeneralMethod() {
+        String missingOptional = "Name not provided";
+        Optional<String> optionalString = Optional.empty();
+        Optional<String> fallbackOptionalString = Optional.ofNullable(missingOptional);
+        assertEquals(fallbackOptionalString, OptionalUtils.or(optionalString, fallbackOptionalString));
+    }
+
+//    Uncomment code when code base is compatible with Java 9
+//    @Test
+//    public void givenOptional_whenEmptyValue_thenCustomMessage() {
+//        assertEquals(Optional.of("Name not provided"), OptionalUtils.getName(Optional.ofNullable(null)));
+//    }
+//
+//    @Test
+//    public void givenOptional_whenValue_thenOptional() {
+//        String name = "Filan Fisteku";
+//        Optional<String> optionalString = Optional.ofNullable(name);
+//        assertEquals(optionalString, OptionalUtils.getName(optionalString));
+//    }
+//
+//    @Test
+//    public void givenGuavaOptional_whenInvoke_thenOptional() {
+//        String name = "Filan Fisteku";
+//        com.google.common.base.Optional<String> stringOptional = com.google.common.base.Optional.of(name);
+//        assertEquals(stringOptional, OptionalUtils.getOptionalGuavaName(stringOptional));
+//    }
+//
+//    @Test
+//    public void givenGuavaOptional_whenNull_thenDefaultText() {
+//        assertEquals(com.google.common.base.Optional.of("Name not provided"), OptionalUtils.getOptionalGuavaName(com.google.common.base.Optional.fromNullable(null)));
+//    }
+} 

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

@@ -23,7 +23,6 @@
 - [Java Global Exception Handler](http://www.baeldung.com/java-global-exception-handler)
 - [How to Get the Size of an Object in Java](http://www.baeldung.com/java-size-of-object)
 - [Common Java Exceptions](http://www.baeldung.com/java-common-exceptions)
-- [Throw Exception in Optional in Java 8](https://www.baeldung.com/java-optional-throw-exception)
 - [Merging java.util.Properties Objects](https://www.baeldung.com/java-merging-properties)
 - [Java – Try with Resources](https://www.baeldung.com/java-try-with-resources)
 - [Guide to Character Encoding](https://www.baeldung.com/java-char-encoding)