Merge branch 'master' into master

algorithms-miscellaneous-4/src/main/java/com/baeldung/algorithms/smallestinteger/SmallestMissingPositiveInteger.java

@@ -0,0 +1,37 @@
+package com.baeldung.algorithms.smallestinteger;
+
+import java.util.Arrays;
+
+public class SmallestMissingPositiveInteger {
+    public static int searchInSortedArray(int[] input) {
+        for (int i = 0; i < input.length; i++) {
+            if (i != input[i]) {
+                return i;
+            }
+        }
+
+        return input.length;
+    }
+
+    public static int searchInUnsortedArraySortingFirst(int[] input) {
+        Arrays.sort(input);
+        return searchInSortedArray(input);
+    }
+
+    public static int searchInUnsortedArrayBooleanArray(int[] input) {
+        boolean[] flags = new boolean[input.length];
+        for (int number : input) {
+            if (number < flags.length) {
+                flags[number] = true;
+            }
+        }
+
+        for (int i = 0; i < flags.length; i++) {
+            if (!flags[i]) {
+                return i;
+            }
+        }
+
+        return flags.length;
+    }
+}

algorithms-miscellaneous-4/src/test/java/com/baeldung/algorithms/smallestinteger/SmallestMissingPositiveIntegerUnitTest.java

@@ -0,0 +1,88 @@
+package com.baeldung.algorithms.smallestinteger;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class SmallestMissingPositiveIntegerUnitTest {
+    @Test
+    void givenArrayWithThreeMissing_whenSearchInSortedArray_thenThree() {
+        int[] input = new int[] {0, 1, 2, 4, 5};
+
+        int result = SmallestMissingPositiveInteger.searchInSortedArray(input);
+
+        assertThat(result).isEqualTo(3);
+    }
+
+    @Test
+    void givenArrayWithOneAndThreeMissing_whenSearchInSortedArray_thenOne() {
+        int[] input = new int[] {0, 2, 4, 5};
+
+        int result = SmallestMissingPositiveInteger.searchInSortedArray(input);
+
+        assertThat(result).isEqualTo(1);
+    }
+
+    @Test
+    void givenArrayWithoutMissingInteger_whenSearchInSortedArray_thenArrayLength() {
+        int[] input = new int[] {0, 1, 2, 3, 4, 5};
+
+        int result = SmallestMissingPositiveInteger.searchInSortedArray(input);
+
+        assertThat(result).isEqualTo(input.length);
+    }
+
+    @Test
+    void givenArrayWithThreeMissing_whenSearchInUnsortedArraySortingFirst_thenThree() {
+        int[] input = new int[] {1, 4, 0, 5, 2};
+
+        int result = SmallestMissingPositiveInteger.searchInUnsortedArraySortingFirst(input);
+
+        assertThat(result).isEqualTo(3);
+    }
+
+    @Test
+    void givenArrayWithOneAndThreeMissing_whenSearchInUnsortedArraySortingFirst_thenOne() {
+        int[] input = new int[] {4, 2, 0, 5};
+
+        int result = SmallestMissingPositiveInteger.searchInUnsortedArraySortingFirst(input);
+
+        assertThat(result).isEqualTo(1);
+    }
+
+    @Test
+    void givenArrayWithoutMissingInteger_whenSearchInUnsortedArraySortingFirst_thenArrayLength() {
+        int[] input = new int[] {4, 5, 1, 3, 0, 2};
+
+        int result = SmallestMissingPositiveInteger.searchInUnsortedArraySortingFirst(input);
+
+        assertThat(result).isEqualTo(input.length);
+    }
+
+    @Test
+    void givenArrayWithThreeMissing_whenSearchInUnsortedArrayBooleanArray_thenThree() {
+        int[] input = new int[] {1, 4, 0, 5, 2};
+
+        int result = SmallestMissingPositiveInteger.searchInUnsortedArrayBooleanArray(input);
+
+        assertThat(result).isEqualTo(3);
+    }
+
+    @Test
+    void givenArrayWithOneAndThreeMissing_whenSearchInUnsortedArrayBooleanArray_thenOne() {
+        int[] input = new int[] {4, 2, 0, 5};
+
+        int result = SmallestMissingPositiveInteger.searchInUnsortedArrayBooleanArray(input);
+
+        assertThat(result).isEqualTo(1);
+    }
+
+    @Test
+    void givenArrayWithoutMissingInteger_whenSearchInUnsortedArrayBooleanArray_thenArrayLength() {
+        int[] input = new int[] {4, 5, 1, 3, 0, 2};
+
+        int result = SmallestMissingPositiveInteger.searchInUnsortedArrayBooleanArray(input);
+
+        assertThat(result).isEqualTo(input.length);
+    }
+}

algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/binarygap/BinaryGap.java

@@ -0,0 +1,17 @@
+package com.baeldung.algorithms.binarygap;
+
+public class BinaryGap {
+    static int calculateBinaryGap(int n) {
+        return calculateBinaryGap(n >>> Integer.numberOfTrailingZeros(n), 0, 0);
+    }
+
+    static int calculateBinaryGap(int n, int current, int maximum) {
+        if (n == 0) {
+            return maximum;
+        } else if ((n & 1) == 0) {
+            return calculateBinaryGap(n >>> 1, current + 1, maximum);
+        } else {
+            return calculateBinaryGap(n >>> 1, 0, Math.max(maximum, current));
+        }
+    }
+}

algorithms-miscellaneous-5/src/test/java/com/baeldung/algorithms/binarygap/BinaryGapUnitTest.java

@@ -0,0 +1,34 @@
+package com.baeldung.algorithms.binarygap;
+
+import static com.baeldung.algorithms.binarygap.BinaryGap.calculateBinaryGap;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class BinaryGapUnitTest {
+
+    @Test public void givenNoOccurrenceOfBoundedZeros_whenCalculateBinaryGap_thenOutputCorrectResult() {
+
+        int result = calculateBinaryGap(63);
+        assertEquals(0, result);
+    }
+
+    @Test public void givenTrailingZeros_whenCalculateBinaryGap_thenOutputCorrectResult() {
+
+        int result = calculateBinaryGap(40);
+        assertEquals(1, result);
+    }
+
+    @Test public void givenSingleOccurrenceOfBoundedZeros_whenCalculateBinaryGap_thenOutputCorrectResult() {
+
+        int result = calculateBinaryGap(9);
+        assertEquals(2, result);
+    }
+
+    @Test public void givenMultipleOccurrenceOfBoundedZeros_whenCalculateBinaryGap_thenOutputCorrectResult() {
+
+        int result = calculateBinaryGap(145);
+        assertEquals(3, result);
+    }
+
+}

core-java-modules/README.md

@@ -5,6 +5,5 @@ This module contains modules about core Java
 ## Relevant articles:
 
 - [Multi-Module Maven Application with Java Modules](https://www.baeldung.com/maven-multi-module-project-java-jpms)
-- [Guide to Java FileChannel](https://www.baeldung.com/java-filechannel)
 - [Understanding the NumberFormatException in Java](https://www.baeldung.com/java-number-format-exception)
 - [Will an Error Be Caught by Catch Block in Java?](https://www.baeldung.com/java-error-catch)

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

@@ -0,0 +1,17 @@
+## Core Java 9
+
+This module contains articles about the improvements to core Java features introduced with Java 9.
+
+### 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)
+- [Java 9 CompletableFuture API Improvements](https://www.baeldung.com/java-9-completablefuture)
+
+#### Relevant articles not in this module:
+
+- [Java 9 Process API Improvements](https://www.baeldung.com/java-9-process-api) (see the [core-java-os](/core-java-os) module)
+

core-java-modules/core-java-9-improvements/pom.xml

@@ -0,0 +1,73 @@
+<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-9</artifactId>
+    <version>0.2-SNAPSHOT</version>
+    <name>core-java-9</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.jayway.awaitility</groupId>
+            <artifactId>awaitility</artifactId>
+            <version>${awaitility.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-runner</artifactId>
+            <version>${junit.platform.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>core-java-9</finalName>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>${maven.compiler.source}</source>
+                    <target>${maven.compiler.target}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <pluginRepositories>
+        <pluginRepository>
+            <id>apache.snapshots</id>
+            <url>http://repository.apache.org/snapshots/</url>
+        </pluginRepository>
+    </pluginRepositories>
+
+    <properties>
+        <!-- testing -->
+        <assertj.version>3.10.0</assertj.version>
+        <junit.platform.version>1.2.0</junit.platform.version>
+        <awaitility.version>1.7.0</awaitility.version>
+        <maven.compiler.source>1.9</maven.compiler.source>
+        <maven.compiler.target>1.9</maven.compiler.target>
+        <guava.version>25.1-jre</guava.version>
+    </properties>
+
+</project>

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

@@ -0,0 +1,11 @@
+## Core Java 9
+
+This module contains articles about Project Jigsaw and the Java Platform Module System (JPMS), introduced with Java 9.
+
+### Relevant Articles:
+
+- [Introduction to Project Jigsaw](http://www.baeldung.com/project-jigsaw-java-modularity)
+- [A Guide to Java 9 Modularity](https://www.baeldung.com/java-9-modularity)
+- [Java 9 java.lang.Module API](https://www.baeldung.com/java-9-module-api)
+
+

core-java-modules/core-java-9-jigsaw/pom.xml

@@ -0,0 +1,35 @@
+<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-9-jigsaw</artifactId>
+    <version>0.2-SNAPSHOT</version>
+    <name>core-java-9</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+
+    <build>
+        <finalName>core-java-9-jigsaw</finalName>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>${maven.compiler.source}</source>
+                    <target>${maven.compiler.target}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <maven.compiler.source>1.9</maven.compiler.source>
+        <maven.compiler.target>1.9</maven.compiler.target>
+    </properties>
+
+</project>

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

@@ -0,0 +1,14 @@
+## Core Java 9
+
+This module contains articles about core Java features that have been introduced in Java 9.
+
+### Relevant Articles:
+
+- [Java 9 New Features](https://www.baeldung.com/new-java-9)
+- [Java 9 Variable Handles Demystified](http://www.baeldung.com/java-variable-handles)
+- [Exploring the New HTTP Client in Java 9 and 11](http://www.baeldung.com/java-9-http-client)
+- [Multi-Release Jar Files](https://www.baeldung.com/java-multi-release-jar)
+- [Ahead of Time Compilation (AoT)](https://www.baeldung.com/ahead-of-time-compilation)
+- [Introduction to Java 9 StackWalking API](https://www.baeldung.com/java-9-stackwalking-api)
+- [Java 9 Platform Logging API](https://www.baeldung.com/java-9-logging-api)
+- [Java 9 Reactive Streams](https://www.baeldung.com/java-9-reactive-streams)

core-java-modules/core-java-9-new-features/pom.xml

@@ -0,0 +1,60 @@
+<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-9-new-features</artifactId>
+    <version>0.2-SNAPSHOT</version>
+    <name>core-java-9</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-runner</artifactId>
+            <version>${junit.platform.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>core-java-9-new-features</finalName>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>${maven.compiler.source}</source>
+                    <target>${maven.compiler.target}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <pluginRepositories>
+        <pluginRepository>
+            <id>apache.snapshots</id>
+            <url>http://repository.apache.org/snapshots/</url>
+        </pluginRepository>
+    </pluginRepositories>
+
+    <properties>
+        <!-- testing -->
+        <assertj.version>3.10.0</assertj.version>
+        <junit.platform.version>1.2.0</junit.platform.version>
+        <maven.compiler.source>1.9</maven.compiler.source>
+        <maven.compiler.target>1.9</maven.compiler.target>
+    </properties>
+
+</project>

core-java-modules/core-java-9/.gitignore

@@ -1,13 +0,0 @@
-*.class
-
-#folders#
-/target
-/neoDb*
-/data
-/src/main/webapp/WEB-INF/classes
-*/META-INF/*
-
-# Packaged files #
-*.jar
-*.war
-*.ear

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

@@ -4,28 +4,13 @@ This module contains articles about Java 9 core features
 
 ### Relevant Articles:
 
-- [Java 9 New Features](https://www.baeldung.com/new-java-9)
-- [New Stream Collectors in Java 9](http://www.baeldung.com/java9-stream-collectors)
-- [Introduction to Project Jigsaw](http://www.baeldung.com/project-jigsaw-java-modularity)
-- [Java 9 Variable Handles Demystified](http://www.baeldung.com/java-variable-handles)
-- [Exploring the New HTTP Client in Java 9 and 11](http://www.baeldung.com/java-9-http-client)
 - [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)
 - [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)
-- [Multi-Release Jar Files](https://www.baeldung.com/java-multi-release-jar)
-- [Ahead of Time Compilation (AoT)](https://www.baeldung.com/ahead-of-time-compilation)
-- [Java 9 Process API Improvements](https://www.baeldung.com/java-9-process-api)
-- [Java 9 java.util.Objects Additions](https://www.baeldung.com/java-9-objects-new)
-- [Java 9 Reactive Streams](https://www.baeldung.com/java-9-reactive-streams)
-- [Java 9 Optional API Additions](https://www.baeldung.com/java-9-optional)
-- [Java 9 CompletableFuture API Improvements](https://www.baeldung.com/java-9-completablefuture)
-- [Introduction to Java 9 StackWalking API](https://www.baeldung.com/java-9-stackwalking-api)
-- [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)
-- [A Guide to Java 9 Modularity](https://www.baeldung.com/java-9-modularity)
-- [Java 9 java.lang.Module API](https://www.baeldung.com/java-9-module-api)
-- [Java 9 Platform Logging API](https://www.baeldung.com/java-9-logging-api)
 - [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/main/java/.gitignore

@@ -1,13 +0,0 @@
-*.class
-
-#folders#
-/target
-/neoDb*
-/data
-/src/main/webapp/WEB-INF/classes
-*/META-INF/*
-
-# Packaged files #
-*.jar
-*.war
-*.ear

core-java-modules/core-java-9/src/test/java/com/baeldung/java9/README.MD

@@ -1,2 +0,0 @@
-### Relevant Artiles:
-- [Filtering a Stream of Optionals in Java](http://www.baeldung.com/java-filter-stream-of-optional)

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

@@ -13,22 +13,11 @@ This module contains articles about core Java input and output (IO)
 - [Differences Between the Java WatchService API and the Apache Commons IO Monitor Library](http://www.baeldung.com/java-watchservice-vs-apache-commons-io-monitor-library)
 - [File Size in Java](http://www.baeldung.com/java-file-size)
 - [Comparing getPath(), getAbsolutePath(), and getCanonicalPath() in Java](http://www.baeldung.com/java-path)
-- [Using Java MappedByteBuffer](http://www.baeldung.com/java-mapped-byte-buffer)
 - [How to Copy a File with Java](http://www.baeldung.com/java-copy-file)
 - [Java – Append Data to a File](http://www.baeldung.com/java-append-to-file)
 - [FileNotFoundException in Java](http://www.baeldung.com/java-filenotfound-exception)
 - [How to Read a File in Java](http://www.baeldung.com/reading-file-in-java)
-- [A Guide To NIO2 Asynchronous File Channel](http://www.baeldung.com/java-nio2-async-file-channel)
-- [A Guide To NIO2 FileVisitor](http://www.baeldung.com/java-nio2-file-visitor)
-- [A Guide To NIO2 File Attribute APIs](http://www.baeldung.com/java-nio2-file-attribute)
-- [Introduction to the Java NIO2 File API](http://www.baeldung.com/java-nio-2-file-api)
 - [Zipping and Unzipping in Java](http://www.baeldung.com/java-compress-and-uncompress)
-- [Java NIO2 Path API](http://www.baeldung.com/java-nio-2-path)
-- [A Guide to WatchService in Java NIO2](http://www.baeldung.com/java-nio2-watchservice)
-- [Guide to Java NIO2 Asynchronous Channel APIs](http://www.baeldung.com/java-nio-2-async-channels)
-- [A Guide to NIO2 Asynchronous Socket Channel](http://www.baeldung.com/java-nio2-async-socket-channel)
-- [Download a File From an URL in Java](http://www.baeldung.com/java-download-file)
-- [Create a Symbolic Link with Java](http://www.baeldung.com/java-symlink)
 - [Quick Use of FilenameFilter](http://www.baeldung.com/java-filename-filter)
 - [Read a File into an ArrayList](https://www.baeldung.com/java-file-to-arraylist)
 - [Guide to Java OutputStream](https://www.baeldung.com/java-outputstream)
@@ -40,6 +29,5 @@ This module contains articles about core Java input and output (IO)
 - [How to Write to a CSV File in Java](https://www.baeldung.com/java-csv)
 - [List Files in a Directory in Java](https://www.baeldung.com/java-list-directory-files)
 - [Java InputStream to Byte Array and ByteBuffer](https://www.baeldung.com/convert-input-stream-to-array-of-bytes)
-- [Introduction to the Java NIO Selector](https://www.baeldung.com/java-nio-selector)
 - [How to Avoid the Java FileNotFoundException When Loading Resources](https://www.baeldung.com/java-classpath-resource-cannot-be-opened)
 - [[More -->]](/core-java-modules/core-java-io-2)

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

@@ -27,12 +27,6 @@
             <version>${hsqldb.version}</version>
             <scope>runtime</scope>
         </dependency>
-        <!-- https://mvnrepository.com/artifact/org.asynchttpclient/async-http-client -->
-        <dependency>
-            <groupId>org.asynchttpclient</groupId>
-            <artifactId>async-http-client</artifactId>
-            <version>${async-http-client.version}</version>
-        </dependency>
         <dependency>
             <groupId>com.opencsv</groupId>
             <artifactId>opencsv</artifactId>
@@ -155,7 +149,6 @@
         <!-- maven plugins -->
         <maven-javadoc-plugin.version>3.0.0-M1</maven-javadoc-plugin.version>
         <hsqldb.version>2.4.0</hsqldb.version>
-        <async-http-client.version>2.4.5</async-http-client.version>
         <!-- Mime Type Libraries -->
         <tika.version>1.18</tika.version>
         <jmime-magic.version>0.1.5</jmime-magic.version>

core-java-modules/core-java-io/src/main/java/com/baeldung/java/nio/selector/README.md

@@ -1,2 +0,0 @@
-###Relevant Articles:
-- [Introduction to the Java NIO Selector](http://www.baeldung.com/java-nio-selector)

core-java-modules/core-java-io/src/test/java/com/baeldung/filechannel/FileChannelUnitTest.java

@@ -1,165 +0,0 @@
-package com.baeldung.filechannel;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-
-import java.io.ByteArrayOutputStream;
-import java.io.FileInputStream;
-import java.io.FileOutputStream;
-import java.io.IOException;
-import java.io.RandomAccessFile;
-import java.nio.ByteBuffer;
-import java.nio.MappedByteBuffer;
-import java.nio.channels.FileChannel;
-import java.nio.channels.FileLock;
-import java.nio.charset.StandardCharsets;
-
-import org.junit.Test;
-
-public class FileChannelUnitTest {
-
-    @Test
-    public void givenFile_whenReadWithFileChannelUsingRandomAccessFile_thenCorrect() throws IOException {
-
-        try (RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r"); 
-            FileChannel channel = reader.getChannel(); 
-            ByteArrayOutputStream out = new ByteArrayOutputStream();) {
-
-            int bufferSize = 1024;
-            if (bufferSize > channel.size()) {
-                bufferSize = (int) channel.size();
-            }
-            ByteBuffer buff = ByteBuffer.allocate(bufferSize);
-
-            while (channel.read(buff) > 0) {
-                out.write(buff.array(), 0, buff.position());
-                buff.clear();
-            }
-
-            String fileContent = new String(out.toByteArray(), StandardCharsets.UTF_8);
-
-            assertEquals("Hello world", fileContent);
-        }
-    }
-
-    @Test
-    public void givenFile_whenReadWithFileChannelUsingFileInputStream_thenCorrect() throws IOException {
-
-        try (ByteArrayOutputStream out = new ByteArrayOutputStream(); 
-            FileInputStream fin = new FileInputStream("src/test/resources/test_read.in"); 
-            FileChannel channel = fin.getChannel();) {
-
-            int bufferSize = 1024;
-            if (bufferSize > channel.size()) {
-                bufferSize = (int) channel.size();
-            }
-            ByteBuffer buff = ByteBuffer.allocate(bufferSize);
-
-            while (channel.read(buff) > 0) {
-                out.write(buff.array(), 0, buff.position());
-                buff.clear();
-            }
-            String fileContent = new String(out.toByteArray(), StandardCharsets.UTF_8);
-
-            assertEquals("Hello world", fileContent);
-        }
-    }
-
-    @Test
-    public void givenFile_whenReadAFileSectionIntoMemoryWithFileChannel_thenCorrect() throws IOException {
-
-        try (RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r"); 
-            FileChannel channel = reader.getChannel(); 
-            ByteArrayOutputStream out = new ByteArrayOutputStream();) {
-
-            MappedByteBuffer buff = channel.map(FileChannel.MapMode.READ_ONLY, 6, 5);
-
-            if (buff.hasRemaining()) {
-                byte[] data = new byte[buff.remaining()];
-                buff.get(data);
-                assertEquals("world", new String(data, StandardCharsets.UTF_8));
-            }
-        }
-    }
-
-    @Test
-    public void whenWriteWithFileChannelUsingRandomAccessFile_thenCorrect() throws IOException {
-        String file = "src/test/resources/test_write_using_filechannel.txt";
-        try (RandomAccessFile writer = new RandomAccessFile(file, "rw"); 
-            FileChannel channel = writer.getChannel();) {
-            ByteBuffer buff = ByteBuffer.wrap("Hello world".getBytes(StandardCharsets.UTF_8));
-
-            channel.write(buff);
-
-            // now we verify whether the file was written correctly
-            RandomAccessFile reader = new RandomAccessFile(file, "r");
-            assertEquals("Hello world", reader.readLine());
-            reader.close();
-        }
-    }
-
-    @Test
-    public void givenFile_whenWriteAFileUsingLockAFileSectionWithFileChannel_thenCorrect() throws IOException {
-        try (RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "rw"); 
-            FileChannel channel = reader.getChannel(); 
-            FileLock fileLock = channel.tryLock(6, 5, Boolean.FALSE);) {
-
-            assertNotNull(fileLock);
-        }
-    }
-
-    @Test
-    public void givenFile_whenReadWithFileChannelGetPosition_thenCorrect() throws IOException {
-
-        try (ByteArrayOutputStream out = new ByteArrayOutputStream(); 
-            RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r"); 
-            FileChannel channel = reader.getChannel();) {
-
-            int bufferSize = 1024;
-            if (bufferSize > channel.size()) {
-                bufferSize = (int) channel.size();
-            }
-            ByteBuffer buff = ByteBuffer.allocate(bufferSize);
-
-            while (channel.read(buff) > 0) {
-                out.write(buff.array(), 0, buff.position());
-                buff.clear();
-            }
-
-            // the original file is 11 bytes long, so that's where the position pointer should be
-            assertEquals(11, channel.position());
-
-            channel.position(4);
-            assertEquals(4, channel.position());
-        }
-    }
-
-    @Test
-    public void whenGetFileSize_thenCorrect() throws IOException {
-
-        try (RandomAccessFile reader = new RandomAccessFile("src/test/resources/test_read.in", "r"); 
-            FileChannel channel = reader.getChannel();) {
-
-            // the original file is 11 bytes long, so that's where the position pointer should be
-            assertEquals(11, channel.size());
-        }
-    }
-
-    @Test
-    public void whenTruncateFile_thenCorrect() throws IOException {
-        String input = "this is a test input";
-
-        FileOutputStream fout = new FileOutputStream("src/test/resources/test_truncate.txt");
-        FileChannel channel = fout.getChannel();
-
-        ByteBuffer buff = ByteBuffer.wrap(input.getBytes());
-        channel.write(buff);
-        buff.flip();
-
-        channel = channel.truncate(5);
-        assertEquals(5, channel.size());
-
-        fout.close();
-        channel.close();
-    }
-}

core-java-modules/core-java-io/src/test/java/com/baeldung/java/nio2/README.md

@@ -1,11 +0,0 @@
-### Relevant Articles:
-- [Introduction to the Java NIO2 File API](http://www.baeldung.com/java-nio-2-file-api)
-- [Java NIO2 Path API](http://www.baeldung.com/java-nio-2-path)
-- [A Guide To NIO2 Asynchronous File Channel](http://www.baeldung.com/java-nio2-async-file-channel)
-- [Guide to Selenium with JUnit / TestNG](http://www.baeldung.com/java-selenium-with-junit-and-testng)
-- [A Guide to NIO2 Asynchronous Socket Channel](http://www.baeldung.com/java-nio2-async-socket-channel)
-- [A Guide To NIO2 FileVisitor](http://www.baeldung.com/java-nio2-file-visitor)
-- [A Guide To NIO2 File Attribute APIs](http://www.baeldung.com/java-nio2-file-attribute)
-- [How to use the Spring FactoryBean?](http://www.baeldung.com/spring-factorybean)
-- [A Guide to WatchService in Java NIO2](http://www.baeldung.com/java-nio2-watchservice)
-- [Guide to Java NIO2 Asynchronous Channel APIs](http://www.baeldung.com/java-nio-2-async-channels)

core-java-modules/core-java-io/src/test/resources/test_truncate.txt

@@ -1 +0,0 @@
-this 

core-java-modules/core-java-io/src/test/resources/test_write_using_filechannel.txt

@@ -1 +0,0 @@
-Hello world

core-java-modules/core-java-lang-oop-3/README.md

@@ -15,4 +15,4 @@ This module contains articles about Object-oriented programming (OOP) in Java
 - [Java Interfaces](https://www.baeldung.com/java-interfaces)
 - [Static and Dynamic Binding in Java](https://www.baeldung.com/java-static-dynamic-binding)
 - [Methods in Java](https://www.baeldung.com/java-methods)
-- [[<-- Prev]](/core-java-modules/core-java-lang-oop-2)
+- [[<-- Prev]](/core-java-modules/core-java-lang-oop-2) [[More -->]](/core-java-modules/core-java-lang-oop-4)

core-java-modules/core-java-lang-oop-4/README.md

@@ -0,0 +1,6 @@
+## Core Java Lang OOP (Part 4)
+
+This module contains articles about Object-oriented programming (OOP) in Java
+
+### Relevant Articles:
+- [[<-- Prev]](/core-java-modules/core-java-lang-oop-3)

core-java-modules/core-java-lang-oop-4/pom.xml

@@ -0,0 +1,57 @@
+<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-lang-oop-4</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-lang-oop-4</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <!-- logging -->
+        <dependency>
+            <groupId>log4j</groupId>
+            <artifactId>log4j</artifactId>
+            <version>${log4j.version}</version>
+        </dependency>
+        <dependency> <!-- needed to bridge to slf4j for projects that use the log4j APIs directly -->
+            <groupId>org.slf4j</groupId>
+            <artifactId>log4j-over-slf4j</artifactId>
+            <version>${org.slf4j.version}</version>
+        </dependency>
+        <!-- test scoped -->
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj-core.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <version>${h2.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>core-java-lang-oop-4</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
+    <properties>
+        <assertj-core.version>3.10.0</assertj-core.version>
+    </properties>
+
+</project>

core-java-modules/core-java-lang-oop-4/src/main/java/com/baeldung/strictfpUsage/Circle.java

@@ -0,0 +1,5 @@
+package com.baeldung.strictfpUsage;
+
+public strictfp interface Circle {
+    double computeArea(double radius);
+}

core-java-modules/core-java-lang-oop-4/src/main/java/com/baeldung/strictfpUsage/ScientificCalculator.java

@@ -0,0 +1,12 @@
+package com.baeldung.strictfpUsage;
+
+public strictfp class ScientificCalculator {
+
+    public double sum(double value1, double value2) {
+        return value1 + value2;
+    }
+
+    public double diff(double value1, double value2) {
+        return value1 - value2;
+    }
+}

core-java-modules/core-java-lang-oop-4/src/test/java/com/baeldung/strictfpUsage/ScientificCalculatorUnitTest.java

@@ -0,0 +1,18 @@
+package com.baeldung.strictfpUsage;
+
+import org.junit.Test;
+
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
+public class ScientificCalculatorUnitTest {
+
+    @Test
+    public void whenMethodOfstrictfpClassInvoked_thenIdenticalResultOnAllPlatforms() {
+        ScientificCalculator calculator = new ScientificCalculator();
+        double result = calculator.sum(23e10, 98e17);
+        assertThat(result, is(9.800000230000001E18));
+        result = calculator.diff(Double.MAX_VALUE, 1.56);
+        assertThat(result, is(1.7976931348623157E308));
+    }
+}

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

@@ -4,10 +4,11 @@ This module contains articles about networking in Java
 
 ### Relevant Articles
 
-- [Checking if a URL Exists in Java](https://www.baeldung.com/java-check-url-exists)
-- [Making a JSON POST Request With HttpURLConnection](https://www.baeldung.com/httpurlconnection-post)
+- [Checking If a URL Exists in Java](https://www.baeldung.com/java-check-url-exists)
+- [Making a JSON POST Request with HttpURLConnection](https://www.baeldung.com/httpurlconnection-post)
 - [Using Curl in Java](https://www.baeldung.com/java-curl)
-- [Do a Simple HTTP Request in Java](http://www.baeldung.com/java-http-request)
-- [Sending Emails with Java](http://www.baeldung.com/java-email)
+- [Do a Simple HTTP Request in Java](https://www.baeldung.com/java-http-request)
+- [Sending Emails with Java](https://www.baeldung.com/java-email)
 - [Authentication with HttpUrlConnection](https://www.baeldung.com/java-http-url-connection)
+- [Download a File from an URL in Java](https://www.baeldung.com/java-download-file)
 - [[<-- Prev]](/core-java-modules/core-java-networking)

core-java-modules/core-java-networking-2/pom.xml

@@ -6,9 +6,10 @@
     <packaging>jar</packaging>
 
     <parent>
-        <groupId>com.baeldung.core-java-modules</groupId>
-        <artifactId>core-java-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-java</relativePath>
     </parent>
 
     <dependencies>
@@ -27,6 +28,11 @@
             <artifactId>mail</artifactId>
             <version>${javax.mail.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.asynchttpclient</groupId>
+            <artifactId>async-http-client</artifactId>
+            <version>${async-http-client.version}</version>
+        </dependency>
     </dependencies>
 
     <build>
@@ -36,5 +42,6 @@
     <properties>
         <httpclient.version>4.5.9</httpclient.version>
         <javax.mail.version>1.5.0-b01</javax.mail.version>
+        <async-http-client.version>2.4.5</async-http-client.version>
     </properties>
 </project>