Merge remote-tracking branch 'upstream/master'

core-java-modules/core-java-arrays-convert-2/README.md

@@ -0,0 +1,5 @@
+## Core Java Arrays - Conversions
+
+This module contains articles about arrays conversion in Java
+
+## Relevant Articles

core-java-modules/core-java-arrays-convert-2/pom.xml

@@ -0,0 +1,24 @@
+<?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-arrays-convert-2</artifactId>
+    <packaging>jar</packaging>
+    <name>core-java-arrays-convert-2</name>
+
+    <parent>
+        <artifactId>core-java-modules</artifactId>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <version>0.0.1-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+    </dependencies>
+
+</project>

core-java-modules/core-java-arrays-convert-2/src/test/java/com/baeldung/array/conversions/classcastexception/ClassCastExceptionUnitTest.java

@@ -0,0 +1,96 @@
+package com.baeldung.array.conversions.classcastexception;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.lang.reflect.Array;
+import java.time.Instant;
+import java.util.stream.Stream;
+
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ClassCastExceptionUnitTest {
+
+    private static Logger LOG = LoggerFactory.getLogger(ClassCastExceptionUnitTest.class);
+
+    Integer[] convertObjectArray() {
+        Object[] objArray = new Object[3];
+        objArray[0] = 1;
+        objArray[1] = 2;
+        objArray[2] = 3;
+        return (Integer[]) objArray;
+    }
+
+    Integer[] getIntegerArray() {
+        Integer[] intArray = new Integer[3];
+        intArray[0] = 1;
+        intArray[1] = 2;
+        intArray[2] = 3;
+        return intArray;
+    }
+
+    Integer[] objArrayToIntArray() {
+        Object[] objArray = new Object[] { 1, 2, 3 };
+        Integer[] intArray = new Integer[objArray.length];
+        for (int i = 0; i < objArray.length; i++) {
+            intArray[i] = (Integer) objArray[i];
+        }
+        return intArray;
+    }
+
+    Integer[] objArrayToIntArrayByStream() {
+        Object[] objArray = new Object[] { 1, 2, 3 };
+        Integer[] intArray = Stream.of(objArray)
+            .toArray(Integer[]::new);
+        return intArray;
+    }
+
+    <T> T[] convertFromObjectArray(Class<T> clazz, Object[] objArray) {
+        T[] targetArray = (T[]) Array.newInstance(clazz, objArray.length);
+        for (int i = 0; i < objArray.length; i++) {
+            if (clazz.isInstance(objArray[i])) {
+                targetArray[i] = clazz.cast(objArray[i]);
+            } else {
+                throw new ClassCastException("Element #" + i + ": Cannot cast " + objArray[i].getClass()
+                    .getName() + " to " + clazz.getName());
+            }
+        }
+        return targetArray;
+    }
+
+    @Test
+    void whenCallingConvertObjectArray_thenClassCastException() {
+        Exception ex = assertThrows(ClassCastException.class, this::convertObjectArray);
+        LOG.error("The exception stacktrace:", ex);
+    }
+
+    @Test
+    void whenCallingIntegerArray_thenCorrect() {
+        assertArrayEquals(new Integer[] { 1, 2, 3 }, getIntegerArray());
+    }
+
+    @Test
+    void whenCallingObjArrayToIntArray_thenCorrect() {
+        assertArrayEquals(new Integer[] { 1, 2, 3 }, objArrayToIntArray());
+    }
+
+    @Test
+    void whenCallingObjArrayToIntArrayByStream_thenCorrect() {
+        assertArrayEquals(new Integer[] { 1, 2, 3 }, objArrayToIntArrayByStream());
+    }
+
+    @Test
+    void whenCallingSingleElementArray_thenCorrect() {
+        assertArrayEquals(new Integer[] { 1, 2, 3 }, convertFromObjectArray(Integer.class, new Object[] { 1, 2, 3 }));
+        assertArrayEquals(new String[] { "I'm Kai", "I'm Liam", "I'm Kevin" },
+            convertFromObjectArray(String.class, new Object[] { "I'm Kai", "I'm Liam", "I'm Kevin" }));
+        //class cast ex:
+        Exception ex = assertThrows(ClassCastException.class,
+            () -> convertFromObjectArray(String.class, new Object[] { "I'm Kai", Instant.now(), "I'm Kevin" }));
+        assertEquals("Element #1: Cannot cast java.time.Instant to java.lang.String", ex.getMessage());
+    }
+
+}

core-java-modules/core-java-collections-maps-8/src/test/java/com/baeldung/map/putnonnullvalueinmap/PutNonNullValueInMapUnitTest.java

@@ -0,0 +1,51 @@
+package com.baeldung.map.putnonnullvalueinmap;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class PutNonNullValueInMapUnitTest {
+
+    private Map<Integer, String> map;
+    private String value;
+
+    @Test
+    void givenMapWithNullValue_whenUsingStreamFilter_thenObtainMapWithNonNullValues() {
+        final Map<Integer, String> nullValueMap = new HashMap<>();
+        nullValueMap.put(1, value);
+
+        final Map<Integer, String> mapWithoutNullValues = nullValueMap.entrySet()
+            .stream()
+            .filter(entry -> Objects.nonNull(entry.getValue()))
+            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+        assertThat(mapWithoutNullValues).isEmpty();
+    }
+
+    @Test
+    void givenNullValue_whenUsingIfStatementWithPutMethod_thenObtainMapWithNonNullValues() {
+        if (value != null) {
+            map.put(1, value);
+        }
+        assertThat(map).isEmpty();
+    }
+
+    @Test
+    void givenNullValue_whenUsingOptionalIfPresentWithPutMethod_thenObtainMapWithNonNullValues() {
+        Optional.ofNullable(value)
+            .ifPresent(nonNullValue -> map.put(1, nonNullValue));
+        assertThat(map).isEmpty();
+    }
+
+    @BeforeEach
+    void init() {
+        value = null;
+        map = new HashMap<>();
+    }
+}

core-java-modules/pom.xml

@@ -76,6 +76,7 @@
         <module>core-java-arrays-guides</module>
         <module>core-java-arrays-multidimensional</module>
         <module>core-java-arrays-convert</module>
+        <module>core-java-arrays-convert-2</module>
         <module>core-java-arrays-operations-basic</module>
         <module>core-java-arrays-operations-basic-2</module>
         <module>core-java-arrays-operations-basic-3</module>

persistence-modules/java-mongodb-2/README.md

@@ -2,14 +2,12 @@
 
 This module contains articles about MongoDB in Java. 
 
-- [Guide to Upsert in MongoDB](https://www.baeldung.com/mongodb-upsert)
 - [Bulk Update of Documents in MongoDB](https://www.baeldung.com/mongodb-bulk-update-documents)
 - [Case Insensitive Sorting in MongoDB](https://www.baeldung.com/java-mongodb-case-insensitive-sorting)
 - [How to Check Field Existence in MongoDB?](https://www.baeldung.com/mongodb-check-field-exists)
 - [Push Operations in MongoDB](https://www.baeldung.com/mongodb-push-operations)
 - [Geospatial Support in MongoDB](https://www.baeldung.com/mongodb-geospatial-support)
-- [MongoDB Aggregations Using Java](https://www.baeldung.com/java-mongodb-aggregations)
 - [Retrieve a Value from MongoDB by Its Key Name](https://www.baeldung.com/mongodb-get-value-by-key-name)
 - [Push and Set Operations in Same MongoDB Update](https://www.baeldung.com/java-mongodb-push-set)
-- [Checking Connection to MongoDB](https://www.baeldung.com/mongodb-check-connection)
+- [MongoDB BSON Guide](https://www.baeldung.com/mongodb-bson)
 - More articles: [[<-- prev]](../java-mongodb)

persistence-modules/java-mongodb/src/main/java/com/baeldung/MongoBsonExample.java → persistence-modules/java-mongodb-2/src/main/java/com/baeldung/MongoBsonExample.java

@@ -1,14 +1,15 @@
 package com.baeldung;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import org.bson.Document;
+
 import com.mongodb.client.MongoClient;
 import com.mongodb.client.MongoClients;
 import com.mongodb.client.MongoCollection;
 import com.mongodb.client.MongoDatabase;
-import org.bson.Document;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
 
 public class MongoBsonExample
 {

persistence-modules/java-mongodb-3/README.md

@@ -3,5 +3,9 @@
 - [Guide to Find in MongoDB](https://www.baeldung.com/mongodb-find)
 - [Query Documents using Document ID in MongoDB](https://www.baeldung.com/mongodb-query-documents-id)
 - [Insert Array Inside an Object in MongoDB](https://www.baeldung.com/java-mongodb-document-insert-array)
-- [Guide to Filters in MongoDB](https://www.baeldung.com/java-mongodb-filters)
 - [Add Field to an Existing MongoDB Bson Filter in Java](https://www.baeldung.com/java-mongodb-add-field-bson-filter)
+- [A Simple Tagging Implementation with MongoDB](http://www.baeldung.com/mongodb-tagging)
+- [Introduction to Morphia – Java ODM for MongoDB](https://www.baeldung.com/mongodb-morphia)
+- [Check Collection Existence in MongoDB](https://www.baeldung.com/java-check-collection-existence-mongodb)
+- [Get Last Inserted Document ID in MongoDB With Java Driver](https://www.baeldung.com/java-mongodb-last-inserted-id)
+- More articles: [[<-- prev]](../java-mongodb-2)

persistence-modules/java-mongodb-3/pom.xml

@@ -19,10 +19,16 @@
             <artifactId>mongo-java-driver</artifactId>
             <version>${mongo.version}</version>
         </dependency>
+        <dependency>
+            <groupId>dev.morphia.morphia</groupId>
+            <artifactId>morphia-core</artifactId>
+            <version>${morphia.version}</version>
+        </dependency>
     </dependencies>
 
     <properties>
         <mongo.version>3.12.11</mongo.version>
+        <morphia.version>2.0.0</morphia.version>
     </properties>
 
 </project>

persistence-modules/java-mongodb/src/main/java/com/baeldung/mongo/CollectionExistence.java → persistence-modules/java-mongodb-3/src/main/java/com/baeldung/mongo/collectionexistence/CollectionExistence.java

@@ -1,4 +1,4 @@
-package com.baeldung.mongo;
+package com.baeldung.mongo.collectionexistence;
 
 import java.util.ArrayList;
 

persistence-modules/java-mongodb/src/main/java/com/baeldung/morphia/domain/Author.java → persistence-modules/java-mongodb-3/src/main/java/com/baeldung/mongo/morphia/domain/Author.java

@@ -1,4 +1,4 @@
-package com.baeldung.morphia.domain;
+package com.baeldung.mongo.morphia.domain;
 
 import java.util.List;
 

persistence-modules/java-mongodb/src/main/java/com/baeldung/morphia/domain/Book.java → persistence-modules/java-mongodb-3/src/main/java/com/baeldung/mongo/morphia/domain/Book.java

@@ -1,10 +1,9 @@
-package com.baeldung.morphia.domain;
+package com.baeldung.mongo.morphia.domain;
 
 import java.time.LocalDateTime;
 import java.util.HashSet;
 import java.util.Set;
 
-import dev.morphia.annotations.Embedded;
 import dev.morphia.annotations.Entity;
 import dev.morphia.annotations.Field;
 import dev.morphia.annotations.Id;

persistence-modules/java-mongodb/src/main/java/com/baeldung/morphia/domain/Publisher.java → persistence-modules/java-mongodb-3/src/main/java/com/baeldung/mongo/morphia/domain/Publisher.java

@@ -1,4 +1,4 @@
-package com.baeldung.morphia.domain;
+package com.baeldung.mongo.morphia.domain;
 
 import org.bson.types.ObjectId;
 

persistence-modules/java-mongodb/src/main/java/com/baeldung/tagging/Post.java → persistence-modules/java-mongodb-3/src/main/java/com/baeldung/mongo/tagging/Post.java

@@ -1,4 +1,4 @@
-package com.baeldung.tagging;
+package com.baeldung.mongo.tagging;
 
 import java.util.List;
 

persistence-modules/java-mongodb/src/main/java/com/baeldung/tagging/TagRepository.java → persistence-modules/java-mongodb-3/src/main/java/com/baeldung/mongo/tagging/TagRepository.java

@@ -1,4 +1,4 @@
-package com.baeldung.tagging;
+package com.baeldung.mongo.tagging;
 
 import java.io.Closeable;
 import java.io.IOException;

persistence-modules/java-mongodb/src/test/java/com/baeldung/mongo/CollectionExistenceLiveTest.java → persistence-modules/java-mongodb-3/src/test/java/com/baeldung/mongo/collectionexistence/CollectionExistenceLiveTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.mongo;
+package com.baeldung.mongo.collectionexistence;
 
 import static org.junit.Assert.assertEquals;
 

persistence-modules/java-mongodb/src/test/java/com/baeldung/morphia/MorphiaManualTest.java → persistence-modules/java-mongodb-3/src/test/java/com/baeldung/mongo/morphia/MorphiaManualTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.morphia;
+package com.baeldung.mongo.morphia;
 
 import static dev.morphia.aggregation.Group.grouping;
 import static dev.morphia.aggregation.Group.push;
@@ -17,9 +17,9 @@
 import org.junit.BeforeClass;
 import org.junit.Test;
 
-import com.baeldung.morphia.domain.Author;
-import com.baeldung.morphia.domain.Book;
-import com.baeldung.morphia.domain.Publisher;
+import com.baeldung.mongo.morphia.domain.Author;
+import com.baeldung.mongo.morphia.domain.Book;
+import com.baeldung.mongo.morphia.domain.Publisher;
 import com.mongodb.client.MongoClients;
 import com.mongodb.client.model.ReturnDocument;
 

persistence-modules/java-mongodb/src/test/java/com/baeldung/tagging/TaggingLiveTest.java → persistence-modules/java-mongodb-3/src/test/java/com/baeldung/mongo/tagging/TaggingLiveTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.tagging;
+package com.baeldung.mongo.tagging;
 
 import java.io.IOException;
 import java.util.Arrays;

persistence-modules/java-mongodb/README.md

@@ -5,12 +5,11 @@ This module contains articles about MongoDB in Java.
 ### Relevant articles:
 
 - [A Guide to MongoDB With Java](https://www.baeldung.com/java-mongodb)
-- [A Simple Tagging Implementation with MongoDB](http://www.baeldung.com/mongodb-tagging)
-- [MongoDB BSON Guide](https://www.baeldung.com/mongodb-bson)
-- [Introduction to Morphia – Java ODM for MongoDB](https://www.baeldung.com/mongodb-morphia)
 - [BSON to JSON Document Conversion in Java](https://www.baeldung.com/java-convert-bson-to-json)
-- [Get Last Inserted Document ID in MongoDB With Java Driver](https://www.baeldung.com/java-mongodb-last-inserted-id)
 - [Update Multiple Fields in a MongoDB Document](https://www.baeldung.com/mongodb-update-multiple-fields)
 - [Update Documents in MongoDB](https://www.baeldung.com/mongodb-update-documents)
-- [Check Collection Existence in MongoDB](https://www.baeldung.com/java-check-collection-existence-mongodb)
-- More articles: [next -->](../java-mongodb-2)
+- [Guide to Filters in MongoDB](https://www.baeldung.com/java-mongodb-filters)
+- [Checking Connection to MongoDB](https://www.baeldung.com/mongodb-check-connection)
+- [MongoDB Aggregations Using Java](https://www.baeldung.com/java-mongodb-aggregations)
+- [Guide to Upsert in MongoDB](https://www.baeldung.com/mongodb-upsert)
+- More articles: [next -->](../java-mongodb-2)