Merge branch 'eugenp:master' into master

akka-modules/README.md

@@ -0,0 +1,3 @@
+## Akka 
+
+This module contains modules about Akka. 

akka-modules/akka-http/pom.xml

@@ -8,7 +8,7 @@
 
     <parent>
         <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
+        <artifactId>akka-modules</artifactId>
         <version>1.0.0-SNAPSHOT</version>
     </parent>
 

akka-modules/akka-streams/pom.xml

@@ -8,7 +8,7 @@
 
     <parent>
         <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
+        <artifactId>akka-modules</artifactId>
         <version>1.0.0-SNAPSHOT</version>
     </parent>
 

akka-modules/pom.xml

@@ -0,0 +1,33 @@
+<?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>akka-modules</artifactId>
+    <name>akka-modules</name>
+    <packaging>pom</packaging>
+
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <modules>
+        <module>akka-http</module>
+        <module>akka-streams</module>
+        <module>spring-akka</module>
+    </modules>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.springframework.boot</groupId>
+                    <artifactId>spring-boot-maven-plugin</artifactId>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
+</project>

akka-modules/spring-akka/pom.xml

@@ -9,7 +9,7 @@
 
     <parent>
         <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
+        <artifactId>akka-modules</artifactId>
         <version>1.0.0-SNAPSHOT</version>
     </parent>
 

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

@@ -12,3 +12,4 @@ This module contains articles about Java 9 core features
 - [Easy Ways to Write a Java InputStream to an OutputStream](https://www.baeldung.com/java-inputstream-to-outputstream)
 - [Private Methods in Java Interfaces](https://www.baeldung.com/java-interface-private-methods)
 - [Java Scanner useDelimiter with Examples](https://www.baeldung.com/java-scanner-usedelimiter)
+- [Is There a Destructor in Java?](https://www.baeldung.com/java-destructor)

core-java-modules/core-java-collections-4/src/main/java/com/baeldung/maps/initialize/EmptyMapInitializer.java

@@ -32,7 +32,7 @@ public class EmptyMapInitializer {
     return emptyMap;
   }
 
-  public Map createGenericEmptyMapUsingMapsObject() {
+  public Map createGenericEmptyMapUsingGuavaMapsObject() {
     Map genericEmptyMap = Maps.<String, Integer>newHashMap();
     return genericEmptyMap;
   }
@@ -43,6 +43,11 @@ public class EmptyMapInitializer {
     return emptyMapUsingGuava;
   }
 
+  public static Map<String, String> createImmutableMapUsingGuava() {
+	    Map<String, String> emptyImmutableMapUsingGuava = ImmutableMap.of();
+	    return emptyImmutableMapUsingGuava;
+  }
+  
   public SortedMap<String, String> createEmptySortedMap() {
     SortedMap<String, String> sortedMap = Collections.emptySortedMap();
     return sortedMap;

core-java-modules/core-java-collections-4/src/test/java/com/baeldung/maps/initialize/EmptyMapInitializerUnitTest.java

@@ -28,4 +28,9 @@ public class EmptyMapInitializerUnitTest {
     assertFalse(emptyMapUsingGuava.isEmpty());
   }
 
+  @Test(expected=UnsupportedOperationException.class)
+  public void givenImmutableEmptyMapUsingGuava_whenAddingEntries_throwsException() {
+    Map<String, String> map = EmptyMapInitializer.createImmutableMapUsingGuava();
+    map.put("key", "value");
+  }
 }

core-java-modules/core-java-collections-conversions-2/README.md

@@ -9,4 +9,4 @@ This module contains articles about conversions among Collection types and array
 - [Converting List to Map With a Custom Supplier](https://www.baeldung.com/list-to-map-supplier)
 - [Arrays.asList vs new ArrayList(Arrays.asList())](https://www.baeldung.com/java-arrays-aslist-vs-new-arraylist)
 - [Iterate Over a Set in Java](https://www.baeldung.com/java-iterate-set)
-- More articles: [[<-- prev]](../java-collections-conversions)
+- More articles: [[<-- prev]](../core-java-collections-conversions)

core-java-modules/core-java-collections-conversions-2/pom.xml

@@ -3,9 +3,9 @@
     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>java-collections-conversions-2</artifactId>
+    <artifactId>core-java-collections-conversions-2</artifactId>
     <version>0.1.0-SNAPSHOT</version>
-    <name>java-collections-conversions-2</name>
+    <name>core-java-collections-conversions-2</name>
     <packaging>jar</packaging>
 
     <parent>
@@ -33,7 +33,7 @@
     </dependencies>
 
     <build>
-        <finalName>java-collections-conversions-2</finalName>
+        <finalName>core-java-collections-conversions-2</finalName>
         <resources>
             <resource>
                 <directory>src/main/resources</directory>

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

@@ -12,4 +12,4 @@ This module contains articles about conversions among Collection types and array
 - [Java 8 Collectors toMap](https://www.baeldung.com/java-collectors-tomap)
 - [Converting Iterable to Collection in Java](https://www.baeldung.com/java-iterable-to-collection)
 - [Converting Iterator to List](https://www.baeldung.com/java-convert-iterator-to-list)
-- More articles: [[next -->]](../java-collections-conversions-2)
+- More articles: [[next -->]](../core-java-collections-conversions-2)

core-java-modules/core-java-collections-conversions/pom.xml

@@ -3,9 +3,9 @@
     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>java-collections-conversions</artifactId>
+    <artifactId>core-java-collections-conversions</artifactId>
     <version>0.1.0-SNAPSHOT</version>
-    <name>java-collections-conversions</name>
+    <name>core-java-collections-conversions</name>
     <packaging>jar</packaging>
 
     <parent>
@@ -28,7 +28,7 @@
     </dependencies>
 
     <build>
-        <finalName>java-collections-conversions</finalName>
+        <finalName>core-java-collections-conversions</finalName>
         <resources>
             <resource>
                 <directory>src/main/resources</directory>

core-java-modules/core-java-collections-maps-5/README.md

@@ -8,3 +8,4 @@
 - [Java Map – keySet() vs. entrySet() vs. values() Methods](https://www.baeldung.com/java-map-entries-methods)
 - [Java IdentityHashMap Class and Its Use Cases](https://www.baeldung.com/java-identityhashmap)
 - [How to Invert a Map in Java](https://www.baeldung.com/java-invert-map)
+- More articles: [[<-- prev]](../core-java-collections-maps-4)

core-java-modules/core-java-collections-maps-5/pom.xml

@@ -3,9 +3,9 @@
     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>java-collections-maps-3</artifactId>
+    <artifactId>core-java-collections-maps-5</artifactId>
     <version>0.1.0-SNAPSHOT</version>
-    <name>java-collections-maps-3</name>
+    <name>core-java-collections-maps-5</name>
     <packaging>jar</packaging>
 
     <parent>

core-java-modules/core-java-date-operations-2/README.md

@@ -12,4 +12,5 @@ This module contains articles about date operations in Java.
 - [Finding Leap Years in Java](https://www.baeldung.com/java-leap-year)
 - [Getting the Week Number From Any Date](https://www.baeldung.com/java-get-week-number)
 - [Subtract Days from a Date in Java](https://www.baeldung.com/java-subtract-days-from-date)
+- [How to Calculate “Time Ago” in Java](https://www.baeldung.com/java-calculate-time-ago)
 - [[<-- Prev]](/core-java-modules/core-java-date-operations-1)

core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/timeago/version7/TimeAgoCalculatorUnitTest.java

@@ -7,7 +7,8 @@ import org.junit.Test;
 
 public class TimeAgoCalculatorUnitTest {
 
-    @Test
+    // fixing tests in BAEL-5647
+    //@Test
     public void timeAgoByTimeGranularityTest() {
         long DAY_IN_MILLIS = 1000 * 60 * 60 * 24;
         Assert.assertEquals("5 seconds ago", TimeAgoCalculator.calculateTimeAgoByTimeGranularity(new Date(System.currentTimeMillis() - (5 * 1000)), TimeGranularity.SECONDS));
@@ -20,7 +21,7 @@ public class TimeAgoCalculatorUnitTest {
         Assert.assertEquals("5 decades ago", TimeAgoCalculator.calculateTimeAgoByTimeGranularity(new Date(System.currentTimeMillis() - (5 * DAY_IN_MILLIS * 365 * 10)), TimeGranularity.DECADES));
     }
 
-    @Test
+    //@Test
     public void humanFriendlyTimeAgoTest() {
         long DAY_IN_MILLIS = 1000 * 60 * 60 * 24;
         Assert.assertEquals("moments ago", TimeAgoCalculator.calculateHumanFriendlyTimeAgo(new Date(System.currentTimeMillis() - (5 * 1000))));
@@ -33,14 +34,14 @@ public class TimeAgoCalculatorUnitTest {
         Assert.assertEquals("several decades ago", TimeAgoCalculator.calculateHumanFriendlyTimeAgo(new Date(System.currentTimeMillis() - (5 * DAY_IN_MILLIS * 365 * 10))));
     }
 
-    @Test
+    //@Test
     public void calculateExactTimeAgoWithJodaTimeTest() {
         Assert.assertEquals("5 hours and 15 minutes and 3 seconds", TimeAgoCalculator.calculateExactTimeAgoWithJodaTime(new Date(System.currentTimeMillis() - (5 * 60 * 60 * 1000 + 15 * 60 * 1000 + 3 * 1000))));
         Assert.assertEquals("5 hours and 1 minute and 1 second", TimeAgoCalculator.calculateExactTimeAgoWithJodaTime(new Date(System.currentTimeMillis() - (5 * 60 * 60 * 1000 + 1 * 60 * 1000 + 1 * 1000))));
         Assert.assertEquals("2 days and 1 minute and 1 second", TimeAgoCalculator.calculateExactTimeAgoWithJodaTime(new Date(System.currentTimeMillis() - (2 * 24 * 60 * 60 * 1000 + 1 * 60 * 1000 + 1 * 1000))));
     }
 
-    @Test
+    //@Test
     public void calculateHumanFriendlyTimeAgoWithJodaTimeTest() {
         long DAY_IN_MILLIS = 1000 * 60 * 60 * 24;
         Assert.assertEquals("moments ago", TimeAgoCalculator.calculateHumanFriendlyTimeAgoWithJodaTime(new Date(System.currentTimeMillis() - (5 * 1000))));

core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/timeago/version8/TimeAgoCalculatorUnitTest.java

@@ -9,7 +9,8 @@ import org.junit.Test;
 
 public class TimeAgoCalculatorUnitTest {
 
-    @Test
+    // fixing test in BAEL-5647
+    //@Test
     public void calculateTimeAgoWithPeriodAndDurationTest() {
         long DAY_IN_MILLIS = 1000 * 60 * 60 * 24;
         Assert.assertEquals("moments ago", TimeAgoCalculator.calculateTimeAgoWithPeriodAndDuration(LocalDateTime.ofInstant(Instant.ofEpochMilli(System.currentTimeMillis()), ZoneId.systemDefault()), ZoneId.systemDefault()));

core-java-modules/core-java-io-conversions-2/src/test/java/com/baeldung/inputstreamtobase64/InputStreamToBase64UnitTest.java

@@ -0,0 +1,49 @@
+package com.baeldung.inputstreamtobase64;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.InputStream;
+import java.util.Base64;
+
+import org.apache.commons.io.IOUtils;
+import org.junit.Test;
+/**
+ * Test the Stream to base64 conversion
+ */
+public class InputStreamToBase64UnitTest {
+    
+    /**
+     * Test stream to base64 conversion
+     * @throws Exception 
+     */
+    @Test
+    public void givenABinaryInputStream_whenItIsConvertedToBase64_thenItCanBeDecoded() throws Exception {
+        // given a binary input stream
+        InputStream sourceStream  = getClass().getClassLoader().getResourceAsStream("logo.png");
+        byte[] sourceBytes = IOUtils.toByteArray(sourceStream);
+
+        // when it is converted to base64
+        String encodedString = Base64.getEncoder().encodeToString(sourceBytes); 
+        assertNotNull(encodedString);
+
+        // then it can be decoded
+        byte[] decodedBytes = Base64.getDecoder().decode(encodedString);
+        assertNotNull(decodedBytes);
+        assertTrue(decodedBytes.length == sourceBytes.length);
+        assertTrue(calculateChecksum(decodedBytes) == calculateChecksum(sourceBytes)); 
+     }
+
+     /**
+      * Calculate a checksum
+      * @param bytes array of bytes to check
+      * @return the total sum of all bytes
+      */
+     private int calculateChecksum(byte[] bytes) {
+        int checksum = 0; 
+        for(int index=0; index < bytes.length; index++) {
+            checksum+=bytes[index]; 
+        }
+        return checksum; 
+     }
+}

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

@@ -8,4 +8,5 @@ This module contains articles about JAR files
 - [Importance of Main Manifest Attribute in a Self-Executing JAR](http://www.baeldung.com/java-jar-executable-manifest-main-class)
 - [Guide to Creating and Running a Jar File in Java](https://www.baeldung.com/java-create-jar)
 - [Get Names of Classes Inside a JAR File](https://www.baeldung.com/jar-file-get-class-names)
-  [Find All Jars Containing Given Class](https://baeldung.com/find-all-jars-containing-given-class/)
+- [Find All Jars Containing Given Class](https://baeldung.com/find-all-jars-containing-given-class/)
+- [Creating JAR Files Programmatically](https://www.baeldung.com/jar-create-programatically)

core-java-modules/core-java-jar/src/main/java/com/baeldung/createjar/Driver.java

@@ -0,0 +1,19 @@
+package com.baeldung.createjar;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.jar.*;
+import com.baeldung.createjar.JarTool;
+
+public class Driver {
+
+    public static void main(String[] args) throws IOException {
+        JarTool tool = new JarTool();
+        tool.startManifest();
+        tool.addToManifest("Main-Class", "com.baeldung.createjar.HelloWorld");
+        JarOutputStream target = tool.openJar("HelloWorld.jar");
+
+        tool.addFile(target, System.getProperty("user.dir") + "\\src\\main\\java", System.getProperty("user.dir") + "\\src\\main\\java\\com\\baeldung\\createjar\\HelloWorld.class");
+        target.close();
+    }
+}

core-java-modules/core-java-jar/src/main/java/com/baeldung/createjar/HelloWorld.java

@@ -0,0 +1,7 @@
+package com.baeldung.createjar;
+
+public class HelloWorld {
+    public static void main(String[] args) {
+        System.out.println("Hello World!");
+    }
+}

core-java-modules/core-java-jar/src/main/java/com/baeldung/createjar/JarTool.java

@@ -0,0 +1,69 @@
+package com.baeldung.createjar;
+
+import java.io.*;
+import java.util.jar.*;
+
+public class JarTool {
+    private Manifest manifest = new Manifest();
+
+    public void addToManifest(String key, String value) {
+        manifest.getMainAttributes()
+            .put(new Attributes.Name(key), value);
+    }
+
+    public void addDirectoryEntry(JarOutputStream target, String parentPath, File dir) throws IOException {
+        String remaining = "";
+        if (parentPath.endsWith(File.separator))
+            remaining = dir.getAbsolutePath()
+                .substring(parentPath.length());
+        else
+            remaining = dir.getAbsolutePath()
+                .substring(parentPath.length() + 1);
+        String name = remaining.replace("\\", "/");
+        if (!name.endsWith("/"))
+            name += "/";
+        JarEntry entry = new JarEntry(name);
+        entry.setTime(dir.lastModified());
+        target.putNextEntry(entry);
+        target.closeEntry();
+    }
+
+    public void addFile(JarOutputStream target, String rootPath, String source) throws IOException {
+        BufferedInputStream in = null;
+        String remaining = "";
+        if (rootPath.endsWith(File.separator))
+            remaining = source.substring(rootPath.length());
+        else
+            remaining = source.substring(rootPath.length() + 1);
+        String name = remaining.replace("\\", "/");
+        JarEntry entry = new JarEntry(name);
+        entry.setTime(new File(source).lastModified());
+        target.putNextEntry(entry);
+        in = new BufferedInputStream(new FileInputStream(source));
+        byte[] buffer = new byte[1024];
+        while (true) {
+            int count = in.read(buffer);
+            if (count == -1)
+                break;
+            target.write(buffer, 0, count);
+        }
+        target.closeEntry();
+        in.close();
+    }
+
+    public JarOutputStream openJar(String jarFile) throws IOException {
+        JarOutputStream target = new JarOutputStream(new FileOutputStream(jarFile), manifest);
+        return target;
+    }
+
+    public void setMainClass(String mainFQCN) {
+        if (mainFQCN != null && !mainFQCN.equals(""))
+            manifest.getMainAttributes()
+                .put(Attributes.Name.MAIN_CLASS, mainFQCN);
+    }
+
+    public void startManifest() {
+        manifest.getMainAttributes()
+            .put(Attributes.Name.MANIFEST_VERSION, "1.0");
+    }
+}

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

@@ -13,4 +13,4 @@ This module contains articles about numbers in Java.
 - [Binary Numbers in Java](https://www.baeldung.com/java-binary-numbers)
 - [Finding the Least Common Multiple in Java](https://www.baeldung.com/java-least-common-multiple)
 - [Binary Numbers in Java](https://www.baeldung.com/java-binary-numbers)
-- More articles: [[<-- prev]](../java-numbers) [[next -->]](../java-numbers-3)
+- More articles: [[<-- prev]](../core-java-numbers) [[next -->]](../core-java-numbers-3)

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

@@ -3,9 +3,9 @@
     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>java-numbers-2</artifactId>
+    <artifactId>core-java-numbers-2</artifactId>
     <version>0.1.0-SNAPSHOT</version>
-    <name>java-numbers-2</name>
+    <name>core-java-numbers-2</name>
     <packaging>jar</packaging>
 
     <parent>
@@ -28,7 +28,7 @@
     </dependencies>
 
     <build>
-        <finalName>java-numbers-2</finalName>
+        <finalName>core-java-numbers-2</finalName>
         <resources>
             <resource>
                 <directory>src/main/resources</directory>