[BAEL-14776] - Deleted README file to fix conflict

algorithms-miscellaneous-3/src/main/java/com/baeldung/folding/FoldingHash.java

@@ -0,0 +1,78 @@
+package com.baeldung.folding;
+
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+/**
+ * Calculate a hash value for the strings using the folding technique.
+ * 
+ * The implementation serves only to the illustration purposes and is far
+ * from being the most efficient. 
+ * 
+ * @author A.Shcherbakov
+ *
+ */
+public class FoldingHash {
+
+    /**
+     * Calculate the hash value of a given string.
+     * 
+     * @param str Assume it is not null
+     * @param groupSize the group size in the folding technique
+     * @param maxValue defines a max value that the hash may acquire (exclusive)     
+     * @return integer value from 0 (inclusive) to maxValue (exclusive)
+     */
+    public int hash(String str, int groupSize, int maxValue) {
+        final int[] codes = this.toAsciiCodes(str);
+        return IntStream.range(0, str.length())
+            .filter(i -> i % groupSize == 0)
+            .mapToObj(i -> extract(codes, i, groupSize))
+            .map(block -> concatenate(block))
+            .reduce(0, (a, b) -> (a + b) % maxValue);
+    }
+
+    /**
+     * Returns a new array of given length whose elements are take from 
+     * the original one starting from the offset.
+     *  
+     * If the original array has not enough elements, the returning array will contain 
+     * element from the offset till the end of the original array.
+     *  
+     * @param numbers original array. Assume it is not null.
+     * @param offset index of the element to start from. Assume it is less than the size of the array 
+     * @param length max size of the resulting array
+     * @return
+     */
+    public int[] extract(int[] numbers, int offset, int length) {
+        final int defect = numbers.length - (offset + length);
+        final int s = defect < 0 ? length + defect : length;
+        int[] result = new int[s];
+        for (int index = 0; index < s; index++) {
+            result[index] = numbers[index + offset];
+        }
+        return result;
+    }
+
+    /**
+     * Concatenate the numbers into a single number as if they were strings.
+     * Assume that the procedure does not suffer from the overflow.
+     * @param numbers integers to concatenate
+     * @return
+     */
+    public int concatenate(int[] numbers) {
+        final String merged = IntStream.of(numbers)
+            .mapToObj(number -> "" + number)
+            .collect(Collectors.joining());
+        return Integer.parseInt(merged, 10);
+    }
+
+    /**
+     * Convert the string into its characters' ASCII codes.
+     * @param str input string
+     * @return
+     */
+    private int[] toAsciiCodes(String str) {
+        return str.chars()
+            .toArray();
+    }
+}

algorithms-miscellaneous-3/src/main/java/com/baeldung/folding/Main.java

@@ -0,0 +1,17 @@
+package com.baeldung.folding;
+
+/**
+ * Code snippet for article "A Guide to the Folding Technique".
+ *  
+ * @author A.Shcherbakov
+ *
+ */
+public class Main {
+
+    public static void main(String... arg) {
+        FoldingHash hasher = new FoldingHash();
+        final String str = "Java language";
+        System.out.println(hasher.hash(str, 2, 100_000));
+        System.out.println(hasher.hash(str, 3, 1_000));
+    }
+}

algorithms-miscellaneous-3/src/test/java/com/baeldung/folding/FoldingHashUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.folding;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class FoldingHashUnitTest {
+
+    @Test
+    public void givenStringJavaLanguage_whenSize2Capacity100000_then48933() throws Exception {
+        final FoldingHash hasher = new FoldingHash();
+        final int value = hasher.hash("Java language", 2, 100_000);
+        assertEquals(value, 48933);
+    }
+
+    @Test
+    public void givenStringVaJaLanguage_whenSize2Capacity100000_thenSameAsJavaLanguage() throws Exception {
+        final FoldingHash hasher = new FoldingHash();
+        final int java = hasher.hash("Java language", 2, 100_000);
+        final int vaja = hasher.hash("vaJa language", 2, 100_000);
+        assertTrue(java == vaja);
+    }
+
+    @Test
+    public void givenSingleElementArray_whenOffset0Size2_thenSingleElement() throws Exception {
+        final FoldingHash hasher = new FoldingHash();
+        final int[] value = hasher.extract(new int[] { 5 }, 0, 2);
+        assertArrayEquals(new int[] { 5 }, value);
+    }
+
+    @Test
+    public void givenFiveElementArray_whenOffset0Size3_thenFirstThreeElements() throws Exception {
+        final FoldingHash hasher = new FoldingHash();
+        final int[] value = hasher.extract(new int[] { 1, 2, 3, 4, 5 }, 0, 3);
+        assertArrayEquals(new int[] { 1, 2, 3 }, value);
+    }
+
+    @Test
+    public void givenFiveElementArray_whenOffset1Size2_thenTwoElements() throws Exception {
+        final FoldingHash hasher = new FoldingHash();
+        final int[] value = hasher.extract(new int[] { 1, 2, 3, 4, 5 }, 1, 2);
+        assertArrayEquals(new int[] { 2, 3 }, value);
+    }
+
+    @Test
+    public void givenFiveElementArray_whenOffset2SizeTooBig_thenElementsToTheEnd() throws Exception {
+        final FoldingHash hasher = new FoldingHash();
+        final int[] value = hasher.extract(new int[] { 1, 2, 3, 4, 5 }, 2, 2000);
+        assertArrayEquals(new int[] { 3, 4, 5 }, value);
+    }
+
+}

autovalue/pom.xml

@@ -29,6 +29,12 @@
                 </exclusion>
             </exclusions>
         </dependency>
+        <dependency>
+            <groupId>com.google.auto.service</groupId>
+            <artifactId>auto-service</artifactId>
+            <version>${auto-service.version}</version>
+            <optional>true</optional>
+        </dependency>
 
         <dependency>
             <groupId>com.google.inject</groupId>
@@ -40,6 +46,7 @@
     <properties>
         <auto-value.version>1.3</auto-value.version>
         <auto-factory.version>1.0-beta5</auto-factory.version>
+        <auto-service.version>1.0-rc5</auto-service.version>
         <guice.version>4.2.0</guice.version>
     </properties>
 

autovalue/src/main/java/com/baeldung/autoservice/BingTranslationServiceProvider.java

@@ -0,0 +1,14 @@
+package com.baeldung.autoservice;
+
+import com.google.auto.service.AutoService;
+
+import java.util.Locale;
+
+@AutoService(TranslationService.class)
+public class BingTranslationServiceProvider implements TranslationService {
+    @Override
+    public String translate(String message, Locale from, Locale to) {
+        // implementation details
+        return message + " (translated by Bing)"; 
+    }
+}

autovalue/src/main/java/com/baeldung/autoservice/GoogleTranslationServiceProvider.java

@@ -0,0 +1,14 @@
+package com.baeldung.autoservice;
+
+import com.google.auto.service.AutoService;
+
+import java.util.Locale;
+
+@AutoService(TranslationService.class)
+public class GoogleTranslationServiceProvider implements TranslationService {
+    @Override
+    public String translate(String message, Locale from, Locale to) {
+        // implementation details
+        return message + " (translated by Google)"; 
+    }
+}

autovalue/src/main/java/com/baeldung/autoservice/TranslationService.java

@@ -0,0 +1,7 @@
+package com.baeldung.autoservice;
+
+import java.util.Locale;
+
+public interface TranslationService {
+    String translate(String message, Locale from, Locale to);
+}

autovalue/src/test/java/com/baeldung/autoservice/TranslationServiceUnitTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.autoservice;
+
+import com.baeldung.autoservice.TranslationService;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.ServiceLoader;
+import java.util.stream.StreamSupport;
+
+import static org.junit.Assert.assertEquals;
+
+public class TranslationServiceUnitTest {
+
+    private ServiceLoader<TranslationService> loader;
+
+    @Before
+    public void setUp() {
+        loader = ServiceLoader.load(TranslationService.class);
+    }
+
+    @Test
+    public void whenServiceLoaderLoads_thenLoadsAllProviders() {
+        long count = StreamSupport.stream(loader.spliterator(), false).count();
+        assertEquals(2, count);
+    }
+
+    @Test
+    public void whenServiceLoaderLoadsGoogleService_thenGoogleIsLoaded() {
+        TranslationService googleService = StreamSupport.stream(loader.spliterator(), false)
+          .filter(p -> p.getClass().getSimpleName().equals("GoogleTranslationServiceProvider"))
+          .findFirst()
+          .get();
+		
+        String message = "message";
+        assertEquals(message + " (translated by Google)", googleService.translate(message, null, null));
+    }
+}

core-java-modules/core-java-8-2/src/main/java/com/baeldung/stream/SkipLimitComparison.java

@@ -0,0 +1,46 @@
+package com.baeldung.stream;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class SkipLimitComparison {
+
+    public static void main(String[] args) {
+        skipExample();
+        limitExample();
+        limitInfiniteStreamExample();
+        getEvenNumbers(10, 10).stream()
+            .forEach(System.out::println);
+    }
+
+    public static void skipExample() {
+        Stream.of(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
+            .filter(i -> i % 2 == 0)
+            .skip(2)
+            .forEach(i -> System.out.print(i + " "));
+    }
+
+    public static void limitExample() {
+        Stream.of(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
+            .filter(i -> i % 2 == 0)
+            .limit(2)
+            .forEach(i -> System.out.print(i + " "));
+    }
+
+    public static void limitInfiniteStreamExample() {
+        Stream.iterate(0, i -> i + 1)
+            .filter(i -> i % 2 == 0)
+            .limit(10)
+            .forEach(System.out::println);
+    }
+
+    private static List<Integer> getEvenNumbers(int offset, int limit) {
+        return Stream.iterate(0, i -> i + 1)
+            .filter(i -> i % 2 == 0)
+            .skip(offset)
+            .limit(limit)
+            .collect(Collectors.toList());
+    }
+
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/forEach/ReverseList.java

@@ -0,0 +1,84 @@
+package com.baeldung.forEach;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+import java.util.function.Consumer;
+
+class ReverseList extends ArrayList<String> {
+
+    List<String> list = Arrays.asList("A", "B", "C", "D");
+
+    Consumer<String> removeElement = s -> {
+        System.out.println(s + " " + list.size());
+        if (s != null && s.equals("A")) {
+            list.remove("D");
+        }
+    };
+
+    @Override
+    public Iterator<String> iterator() {
+
+        final int startIndex = this.size() - 1;
+        final List<String> list = this;
+        return new Iterator<String>() {
+
+            int currentIndex = startIndex;
+
+            @Override
+            public boolean hasNext() {
+                return currentIndex >= 0;
+            }
+
+            @Override
+            public String next() {
+                String next = list.get(currentIndex);
+                currentIndex--;
+                return next;
+            }
+
+            @Override
+            public void remove() {
+                throw new UnsupportedOperationException();
+            }
+        };
+    }
+
+    public void forEach(Consumer<? super String> action) {
+        for (String s : this) {
+            action.accept(s);
+        }
+    }
+
+    public void iterateParallel() {
+        list.forEach(System.out::print);
+        System.out.print(" ");
+        list.parallelStream().forEach(System.out::print);
+    }
+
+    public void iterateReverse() {
+        List<String> myList = new ReverseList();
+        myList.addAll(list);
+        myList.forEach(System.out::print);
+        System.out.print(" ");
+        myList.stream().forEach(System.out::print);
+    }
+
+    public void removeInCollectionForEach() {
+        list.forEach(removeElement);
+    }
+
+    public void removeInStreamForEach() {
+        list.stream().forEach(removeElement);
+    }
+
+    public static void main(String[] argv) {
+
+        ReverseList collectionForEach = new ReverseList();
+        collectionForEach.iterateParallel();
+        collectionForEach.iterateReverse();
+        collectionForEach.removeInCollectionForEach();
+        collectionForEach.removeInStreamForEach();
+    }
+}

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

@@ -1,26 +1,35 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	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">
+	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>
+	<modelVersion>4.0.0</modelVersion>
-    <groupId>com.baeldung.exception.numberformat</groupId>
+	<groupId>com.baeldung.exception.numberformat</groupId>
-    <artifactId>core-java-exceptions</artifactId>
+	<artifactId>core-java-exceptions</artifactId>
-    <version>0.0.1-SNAPSHOT</version>
+	<version>0.0.1-SNAPSHOT</version>
-    <name>core-java-exceptions</name>
+	<name>core-java-exceptions</name>
 
-    <parent>
+	<parent>
-        <groupId>com.baeldung</groupId>
+		<groupId>com.baeldung</groupId>
-        <artifactId>parent-java</artifactId>
+		<artifactId>parent-java</artifactId>
-        <version>0.0.1-SNAPSHOT</version>
+		<version>0.0.1-SNAPSHOT</version>
-        <relativePath>../../parent-java</relativePath>
+		<relativePath>../../parent-java</relativePath>
-    </parent>
+	</parent>
 
-    <dependencies>
+	<properties>
-        <dependency>
+		<commons-lang3.version>3.9</commons-lang3.version>
-            <groupId>junit</groupId>
+	</properties>
-            <artifactId>junit</artifactId>
+
-            <version>4.12</version>
+	<dependencies>
-            <scope>test</scope>
+		<dependency>
-        </dependency>
+			<groupId>junit</groupId>
-    </dependencies>
+			<artifactId>junit</artifactId>
+			<version>4.12</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.apache.commons</groupId>
+			<artifactId>commons-lang3</artifactId>
+			<version>${commons-lang3.version}</version>
+		</dependency>
+	</dependencies>
 
 </project>

core-java-modules/core-java-exceptions/src/test/java/com/baeldung/exception/error/ErrorGeneratorUnitTest.java

@@ -1,7 +1,6 @@
-package com.baeldung.error;
+package com.baeldung.exception.error;
 
 import org.junit.Assert;
-import org.junit.Before;
 import org.junit.Test;
 
 public class ErrorGeneratorUnitTest {

core-java-modules/core-java-lambdas/README.MD

@@ -1,3 +0,0 @@
-## Relevant articles:
-
-- [Why Do Local Variables Used in Lambdas Have to Be Final or Effectively Final?](https://www.baeldung.com/java-lambda-effectively-final-local-variables)

core-java-modules/core-java-lang-oop-2/src/main/java/com/baeldung/rawtype/RawTypeDemo.java

@@ -0,0 +1,25 @@
+package com.baeldung.rawtype;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class RawTypeDemo {
+
+	public static void main(String[] args) {
+		RawTypeDemo rawTypeDemo = new RawTypeDemo();
+		rawTypeDemo.methodA();
+	}
+
+	public void methodA() {
+		// parameterized type
+		List<String> listStr = new ArrayList<>();
+		listStr.add("Hello Folks!");
+		methodB(listStr);
+		String s = listStr.get(1); // ClassCastException at run time
+	}
+
+	public void methodB(List rawList) { // Inexpressive raw type
+		rawList.add(1); // Unsafe operation
+	}
+
+}

java-collections-conversions/src/test/java/com/baeldung/convertiteratortolist/ConvertIteratorToListServiceUnitTest.java

@@ -0,0 +1,100 @@
+package com.baeldung.convertiteratortolist;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.collection.IsCollectionWithSize.hasSize;
+import static org.hamcrest.collection.IsIterableContainingInAnyOrder.containsInAnyOrder;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+
+import org.apache.commons.collections4.IteratorUtils;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Lists;
+
+public class ConvertIteratorToListServiceUnitTest {
+
+    Iterator<Integer> iterator;
+
+    @Before
+    public void setUp() throws Exception {
+        iterator = Arrays.asList(1, 2, 3)
+            .iterator();
+    }
+
+    @Test
+    public void givenAnIterator_whenConvertIteratorToListUsingWhileLoop_thenReturnAList() {
+
+        List<Integer> actualList = new ArrayList<Integer>();
+
+        // Convert Iterator to List using while loop dsf
+        while (iterator.hasNext()) {
+            actualList.add(iterator.next());
+        }
+
+        assertThat(actualList, hasSize(3));
+        assertThat(actualList, containsInAnyOrder(1, 2, 3));
+    }
+
+    @Test
+    public void givenAnIterator_whenConvertIteratorToListAfterJava8_thenReturnAList() {
+        List<Integer> actualList = new ArrayList<Integer>();
+
+        // Convert Iterator to List using Java 8
+        iterator.forEachRemaining(actualList::add);
+
+        assertThat(actualList, hasSize(3));
+        assertThat(actualList, containsInAnyOrder(1, 2, 3));
+    }
+
+    @Test
+    public void givenAnIterator_whenConvertIteratorToListJava8Stream_thenReturnAList() {
+
+        // Convert iterator to iterable
+        Iterable<Integer> iterable = () -> iterator;
+
+        // Extract List from stream
+        List<Integer> actualList = StreamSupport
+            .stream(iterable.spliterator(), false)
+            .collect(Collectors.toList());
+
+        assertThat(actualList, hasSize(3));
+        assertThat(actualList, containsInAnyOrder(1, 2, 3));
+    }
+
+    @Test
+    public void givenAnIterator_whenConvertIteratorToImmutableListWithGuava_thenReturnAList() {
+
+        // Convert Iterator to an Immutable list using Guava library in Java
+        List<Integer> actualList = ImmutableList.copyOf(iterator);
+
+        assertThat(actualList, hasSize(3));
+        assertThat(actualList, containsInAnyOrder(1, 2, 3));
+    }
+
+    @Test
+    public void givenAnIterator_whenConvertIteratorToMutableListWithGuava_thenReturnAList() {
+
+        // Convert Iterator to a mutable list using Guava library in Java
+        List<Integer> actualList = Lists.newArrayList(iterator);
+
+        assertThat(actualList, hasSize(3));
+        assertThat(actualList, containsInAnyOrder(1, 2, 3));
+    }
+
+    @Test
+    public void givenAnIterator_whenConvertIteratorToMutableListWithApacheCommons_thenReturnAList() {
+
+        // Convert Iterator to a mutable list using Apache Commons library in Java
+        List<Integer> actualList = IteratorUtils.toList(iterator);
+
+        assertThat(actualList, hasSize(3));
+        assertThat(actualList, containsInAnyOrder(1, 2, 3));
+    }
+}

java-streams/src/test/java/com/baeldung/intstreams/conversion/IntStreamsConversionsUnitTest.java

@@ -0,0 +1,40 @@
+package com.baeldung.intstreams.conversion;
+
+import org.junit.Test;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class IntStreamsConversionsUnitTest {
+
+    @Test
+    public void intStreamToArray() {
+        int[] first50EvenNumbers = IntStream.iterate(0, i -> i + 2)
+                .limit(50)
+                .toArray();
+
+        assertThat(first50EvenNumbers).hasSize(50);
+        assertThat(first50EvenNumbers[2]).isEqualTo(4);
+    }
+
+    @Test
+    public void intStreamToList() {
+        List<Integer> first50IntegerNumbers = IntStream.range(0, 50)
+                .boxed()
+                .collect(Collectors.toList());
+
+        assertThat(first50IntegerNumbers).hasSize(50);
+        assertThat(first50IntegerNumbers.get(2)).isEqualTo(2);
+    }
+
+    @Test
+    public void intStreamToString() {
+        String first3numbers = IntStream.of(0, 1, 2)
+                .mapToObj(String::valueOf)
+                .collect(Collectors.joining(", ", "[", "]"));
+
+        assertThat(first3numbers).isEqualTo("[0, 1, 2]");
+    }
+}

libraries-2/pom.xml

@@ -50,6 +50,26 @@
 			<artifactId>picocli</artifactId>
 			<version>${picocli.version}</version>
 		</dependency>
+        <dependency>
+            <groupId>org.ejml</groupId>
+            <artifactId>ejml-all</artifactId>
+            <version>${ejml.version}</version>
+        </dependency>
+		<dependency>
+			<groupId>org.nd4j</groupId>
+			<artifactId>nd4j-native</artifactId>
+			<version>${nd4j.version}</version>
+		</dependency>
+        <dependency>
+            <groupId>org.la4j</groupId>
+            <artifactId>la4j</artifactId>
+            <version>${la4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>colt</groupId>
+            <artifactId>colt</artifactId>
+            <version>${colt.version}</version>
+        </dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter</artifactId>
@@ -93,10 +113,22 @@
 			<scope>test</scope>
 		</dependency>
 
-                <dependency>
+        <dependency>
-                    <groupId>edu.uci.ics</groupId>
+            <groupId>edu.uci.ics</groupId>
-                    <artifactId>crawler4j</artifactId>
+            <artifactId>crawler4j</artifactId>
-                    <version>${crawler4j.version}</version>
+            <version>${crawler4j.version}</version>
+		</dependency>
+
+		<!-- Benchmarking -->
+		<dependency>
+			<groupId>org.openjdk.jmh</groupId>
+			<artifactId>jmh-core</artifactId>
+			<version>${jmh.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.openjdk.jmh</groupId>
+			<artifactId>jmh-generator-annprocess</artifactId>
+			<version>${jmh.version}</version>
 		</dependency>
           
 	</dependencies>
@@ -109,5 +141,10 @@
 		<chronicle.map.version>3.17.2</chronicle.map.version>
         <crawler4j.version>4.4.0</crawler4j.version>
 		<spring-boot-starter.version>2.1.4.RELEASE</spring-boot-starter.version>
+		<ejml.version>0.38</ejml.version>
+		<nd4j.version>1.0.0-beta4</nd4j.version>
+		<colt.version>1.2.0</colt.version>
+		<la4j.version>0.6.0</la4j.version>
+		<jmh.version>1.19</jmh.version>
 	</properties>
 </project>

libraries-2/src/test/java/com/baeldung/matrices/MatrixMultiplicationBenchmarking.java

@@ -0,0 +1,9 @@
+package com.baeldung.matrices;
+
+public class MatrixMultiplicationBenchmarking {
+
+    public static void main(String[] args) throws Exception {
+        org.openjdk.jmh.Main.main(args);
+    }
+
+}

libraries-2/src/test/java/com/baeldung/matrices/apache/RealMatrixUnitTest.java

@@ -0,0 +1,47 @@
+package com.baeldung.matrices.apache;
+
+import org.apache.commons.math3.linear.Array2DRowRealMatrix;
+import org.apache.commons.math3.linear.RealMatrix;
+import org.junit.jupiter.api.Test;
+import org.openjdk.jmh.annotations.*;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@BenchmarkMode(Mode.AverageTime)
+@Fork(value = 2)
+@Warmup(iterations = 5)
+@Measurement(iterations = 10)
+public class RealMatrixUnitTest {
+
+    @Test
+    @Benchmark
+    public void givenTwoMatrices_whenMultiply_thenMultiplicatedMatrix() {
+        RealMatrix firstMatrix = new Array2DRowRealMatrix(
+          new double[][] {
+            new double[] {1d, 5d},
+            new double[] {2d, 3d},
+            new double[] {1d ,7d}
+          }
+        );
+
+        RealMatrix secondMatrix = new Array2DRowRealMatrix(
+          new double[][] {
+            new double[] {1d, 2d, 3d, 7d},
+            new double[] {5d, 2d, 8d, 1d}
+          }
+        );
+
+        RealMatrix expected = new Array2DRowRealMatrix(
+          new double[][] {
+            new double[] {26d, 12d, 43d, 12d},
+            new double[] {17d, 10d, 30d, 17d},
+            new double[] {36d, 16d, 59d, 14d}
+          }
+        );
+
+        RealMatrix actual = firstMatrix.multiply(secondMatrix);
+
+        assertThat(actual).isEqualTo(expected);
+    }
+
+}

libraries-2/src/test/java/com/baeldung/matrices/colt/DoubleMatrix2DUnitTest.java

@@ -0,0 +1,51 @@
+package com.baeldung.matrices.colt;
+
+import cern.colt.matrix.DoubleFactory2D;
+import cern.colt.matrix.DoubleMatrix2D;
+import cern.colt.matrix.linalg.Algebra;
+import org.junit.jupiter.api.Test;
+import org.openjdk.jmh.annotations.*;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@BenchmarkMode(Mode.AverageTime)
+@Fork(value = 2)
+@Warmup(iterations = 5)
+@Measurement(iterations = 10)
+public class DoubleMatrix2DUnitTest {
+
+    @Test
+    @Benchmark
+    public void givenTwoMatrices_whenMultiply_thenMultiplicatedMatrix() {
+        DoubleFactory2D doubleFactory2D = DoubleFactory2D.dense;
+
+        DoubleMatrix2D firstMatrix = doubleFactory2D.make(
+          new double[][] {
+            new double[] {1d, 5d},
+            new double[] {2d, 3d},
+            new double[] {1d ,7d}
+          }
+        );
+
+        DoubleMatrix2D secondMatrix = doubleFactory2D.make(
+          new double[][] {
+            new double[] {1d, 2d, 3d, 7d},
+            new double[] {5d, 2d, 8d, 1d}
+          }
+        );
+
+        DoubleMatrix2D expected = doubleFactory2D.make(
+          new double[][] {
+            new double[] {26d, 12d, 43d, 12d},
+            new double[] {17d, 10d, 30d, 17d},
+            new double[] {36d, 16d, 59d, 14d}
+          }
+        );
+
+        Algebra algebra = new Algebra();
+        DoubleMatrix2D actual = algebra.mult(firstMatrix, secondMatrix);
+
+        assertThat(actual).isEqualTo(expected);
+    }
+
+}

libraries-2/src/test/java/com/baeldung/matrices/ejml/SimpleMatrixUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.matrices.ejml;
+
+import org.ejml.simple.SimpleMatrix;
+import org.junit.jupiter.api.Test;
+import org.openjdk.jmh.annotations.*;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@BenchmarkMode(Mode.AverageTime)
+@Fork(value = 2)
+@Warmup(iterations = 5)
+@Measurement(iterations = 10)
+public class SimpleMatrixUnitTest {
+
+    @Test
+    @Benchmark
+    public void givenTwoMatrices_whenMultiply_thenMultiplicatedMatrix() {
+        SimpleMatrix firstMatrix = new SimpleMatrix(
+          new double[][] {
+            new double[] {1d, 5d},
+            new double[] {2d, 3d},
+            new double[] {1d ,7d}
+          }
+        );
+
+        SimpleMatrix secondMatrix = new SimpleMatrix(
+          new double[][] {
+            new double[] {1d, 2d, 3d, 7d},
+            new double[] {5d, 2d, 8d, 1d}
+          }
+        );
+
+        SimpleMatrix expected = new SimpleMatrix(
+          new double[][] {
+            new double[] {26d, 12d, 43d, 12d},
+            new double[] {17d, 10d, 30d, 17d},
+            new double[] {36d, 16d, 59d, 14d}
+          }
+        );
+
+        SimpleMatrix actual = firstMatrix.mult(secondMatrix);
+
+        assertThat(actual).matches(m -> m.isIdentical(expected, 0d));
+    }
+
+}

libraries-2/src/test/java/com/baeldung/matrices/homemade/HomemadeMatrixUnitTest.java

@@ -0,0 +1,58 @@
+package com.baeldung.matrices.homemade;
+
+import org.junit.jupiter.api.Test;
+import org.openjdk.jmh.annotations.*;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@BenchmarkMode(Mode.AverageTime)
+@Fork(value = 2)
+@Warmup(iterations = 5)
+@Measurement(iterations = 10)
+public class HomemadeMatrixUnitTest {
+
+    @Test
+    @Benchmark
+    public void givenTwoMatrices_whenMultiply_thenMultiplicatedMatrix() {
+        double[][] firstMatrix = {
+          new double[]{1d, 5d},
+          new double[]{2d, 3d},
+          new double[]{1d, 7d}
+        };
+
+        double[][] secondMatrix = {
+          new double[]{1d, 2d, 3d, 7d},
+          new double[]{5d, 2d, 8d, 1d}
+        };
+
+        double[][] expected = {
+          new double[]{26d, 12d, 43d, 12d},
+          new double[]{17d, 10d, 30d, 17d},
+          new double[]{36d, 16d, 59d, 14d}
+        };
+
+        double[][] actual = multiplyMatrices(firstMatrix, secondMatrix);
+
+        assertThat(actual).isEqualTo(expected);
+    }
+
+    private double[][] multiplyMatrices(double[][] firstMatrix, double[][] secondMatrix) {
+        double[][] result = new double[firstMatrix.length][secondMatrix[0].length];
+
+        for (int row = 0; row < result.length; row++) {
+            for (int col = 0; col < result[row].length; col++) {
+                result[row][col] = multiplyMatricesCell(firstMatrix, secondMatrix, row, col);
+            }
+        }
+
+        return result;
+    }
+
+    private double multiplyMatricesCell(double[][] firstMatrix, double[][] secondMatrix, int row, int col) {
+        double cell = 0;
+        for (int i = 0; i < secondMatrix.length; i++) {
+            cell += firstMatrix[row][i] * secondMatrix[i][col];
+        }
+        return cell;
+    }
+}

libraries-2/src/test/java/com/baeldung/matrices/la4j/Basic2DMatrixUnitTest.java

@@ -0,0 +1,47 @@
+package com.baeldung.matrices.la4j;
+
+import org.junit.jupiter.api.Test;
+import org.la4j.Matrix;
+import org.la4j.matrix.dense.Basic2DMatrix;
+import org.openjdk.jmh.annotations.*;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@BenchmarkMode(Mode.AverageTime)
+@Fork(value = 2)
+@Warmup(iterations = 5)
+@Measurement(iterations = 10)
+public class Basic2DMatrixUnitTest {
+
+    @Test
+    @Benchmark
+    public void givenTwoMatrices_whenMultiply_thenMultiplicatedMatrix() {
+        Matrix firstMatrix = new Basic2DMatrix(
+          new double[][]{
+            new double[]{1d, 5d},
+            new double[]{2d, 3d},
+            new double[]{1d, 7d}
+          }
+        );
+
+        Matrix secondMatrix = new Basic2DMatrix(
+          new double[][]{
+            new double[]{1d, 2d, 3d, 7d},
+            new double[]{5d, 2d, 8d, 1d}
+          }
+        );
+
+        Matrix expected = new Basic2DMatrix(
+          new double[][]{
+            new double[]{26d, 12d, 43d, 12d},
+            new double[]{17d, 10d, 30d, 17d},
+            new double[]{36d, 16d, 59d, 14d}
+          }
+        );
+
+        Matrix actual = firstMatrix.multiply(secondMatrix);
+
+        assertThat(actual).isEqualTo(expected);
+    }
+
+}

libraries-2/src/test/java/com/baeldung/matrices/nd4j/INDArrayUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.matrices.nd4j;
+
+import org.junit.jupiter.api.Test;
+import org.nd4j.linalg.api.ndarray.INDArray;
+import org.nd4j.linalg.factory.Nd4j;
+import org.openjdk.jmh.annotations.*;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@BenchmarkMode(Mode.AverageTime)
+@Fork(value = 2)
+@Warmup(iterations = 5)
+@Measurement(iterations = 10)
+public class INDArrayUnitTest {
+
+    @Test
+    public void givenTwoMatrices_whenMultiply_thenMultiplicatedMatrix() {
+        INDArray firstMatrix = Nd4j.create(
+          new double[][]{
+            new double[]{1d, 5d},
+            new double[]{2d, 3d},
+            new double[]{1d, 7d}
+          }
+        );
+
+        INDArray secondMatrix = Nd4j.create(
+          new double[][] {
+            new double[] {1d, 2d, 3d, 7d},
+            new double[] {5d, 2d, 8d, 1d}
+          }
+        );
+
+        INDArray expected = Nd4j.create(
+          new double[][] {
+            new double[] {26d, 12d, 43d, 12d},
+            new double[] {17d, 10d, 30d, 17d},
+            new double[] {36d, 16d, 59d, 14d}
+          }
+        );
+
+        INDArray actual = firstMatrix.mmul(secondMatrix);
+
+        assertThat(actual).isEqualTo(expected);
+    }
+
+}

libraries-server/pom.xml

@@ -96,6 +96,19 @@
              <artifactId>smack-java7</artifactId>
              <version>${smack.version}</version>
          </dependency>
+
+        <!-- NanoHTTPD -->
+        <dependency>
+            <groupId>org.nanohttpd</groupId>
+            <artifactId>nanohttpd</artifactId>
+            <version>${nanohttpd.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.nanohttpd</groupId>
+            <artifactId>nanohttpd-nanolets</artifactId>
+            <version>${nanohttpd.version}</version>
+        </dependency>
+
     </dependencies>
 
     <properties>
@@ -108,6 +121,7 @@
         <tomcat.version>8.5.24</tomcat.version>
         <smack.version>4.3.1</smack.version>
 		<eclipse.paho.client.mqttv3.version>1.2.0</eclipse.paho.client.mqttv3.version>
+		<nanohttpd.version>2.3.1</nanohttpd.version>
     </properties>
 
 </project>

libraries-server/src/main/java/com/baeldung/nanohttpd/ApplicationController.java

@@ -0,0 +1,38 @@
+package com.baeldung.nanohttpd;
+
+import fi.iki.elonen.NanoHTTPD;
+import fi.iki.elonen.router.RouterNanoHTTPD;
+
+import java.io.IOException;
+
+public class ApplicationController extends RouterNanoHTTPD {
+
+    ApplicationController() throws IOException {
+        super(8072);
+        addMappings();
+        start(NanoHTTPD.SOCKET_READ_TIMEOUT, false);
+    }
+
+    @Override
+    public void addMappings() {
+        addRoute("/", IndexHandler.class);
+        addRoute("/users", UserHandler.class);
+    }
+
+    public static class UserHandler extends DefaultHandler {
+        @Override
+        public String getText() {
+            return "UserA, UserB, UserC";
+        }
+
+        @Override
+        public String getMimeType() {
+            return MIME_PLAINTEXT;
+        }
+
+        @Override
+        public Response.IStatus getStatus() {
+            return Response.Status.OK;
+        }
+    }
+}

libraries-server/src/main/java/com/baeldung/nanohttpd/ItemGetController.java

@@ -0,0 +1,22 @@
+package com.baeldung.nanohttpd;
+
+import fi.iki.elonen.NanoHTTPD;
+
+import java.io.IOException;
+
+public class ItemGetController extends NanoHTTPD {
+
+    ItemGetController() throws IOException {
+        super(8071);
+        start(NanoHTTPD.SOCKET_READ_TIMEOUT, false);
+    }
+
+    @Override
+    public Response serve(IHTTPSession session) {
+        if (session.getMethod() == Method.GET) {
+            String itemIdRequestParam = session.getParameters().get("itemId").get(0);
+            return newFixedLengthResponse("Requested itemId = " + itemIdRequestParam);
+        }
+        return newFixedLengthResponse(Response.Status.NOT_FOUND, MIME_PLAINTEXT, "The requested resource does not exist");
+    }
+}

libraries-server/src/test/java/com/baeldung/nanohttpd/ApplicationControllerUnitTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.nanohttpd;
+
+import org.apache.commons.io.IOUtils;
+import org.apache.http.HttpResponse;
+import org.apache.http.client.HttpClient;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.junit.Assert.*;
+
+public class ApplicationControllerUnitTest {
+
+    private static final String BASE_URL = "http://localhost:8072/";
+    private static final HttpClient CLIENT = HttpClientBuilder.create().build();
+
+    @BeforeClass
+    public static void setUp() throws IOException {
+        new ApplicationController();
+    }
+
+    @Test
+    public void givenServer_whenRootRouteRequested_thenHelloWorldReturned() throws IOException {
+        HttpResponse response = CLIENT.execute(new HttpGet(BASE_URL));
+        assertTrue(IOUtils.toString(response.getEntity().getContent()).contains("Hello world!"));
+        assertEquals(200, response.getStatusLine().getStatusCode());
+    }
+
+    @Test
+    public void givenServer_whenUsersRequested_thenThenAllUsersReturned() throws IOException {
+        HttpResponse response = CLIENT.execute(new HttpGet(BASE_URL + "users"));
+        assertEquals("UserA, UserB, UserC", IOUtils.toString(response.getEntity().getContent()));
+    }
+}

libraries-server/src/test/java/com/baeldung/nanohttpd/ItemGetControllerUnitTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.nanohttpd;
+
+import static org.junit.Assert.*;
+
+import org.apache.commons.io.IOUtils;
+import org.apache.http.HttpResponse;
+import org.apache.http.client.HttpClient;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.io.IOException;
+
+public class ItemGetControllerUnitTest {
+
+    private static final String URL = "http://localhost:8071";
+    private static final HttpClient CLIENT = HttpClientBuilder.create().build();
+
+    @BeforeClass
+    public static void setUp() throws IOException {
+        new ItemGetController();
+    }
+
+    @Test
+    public void givenServer_whenDoingGet_thenParamIsReadCorrectly() throws IOException {
+        HttpResponse response = CLIENT.execute(new HttpGet(URL + "?itemId=1234"));
+        assertEquals("Requested itemId = 1234", IOUtils.toString(response.getEntity().getContent()));
+    }
+
+    @Test
+    public void givenServer_whenDoingPost_then404IsReturned() throws IOException {
+        HttpResponse response = CLIENT.execute(new HttpPost(URL));
+        assertEquals(404, response.getStatusLine().getStatusCode());
+    }
+}

parent-boot-performance/README.md

@@ -0,0 +1 @@
+This is a parent module for projects that want to take advantage of the latest Spring Boot improvements/features.

parent-boot-performance/pom.xml

@@ -0,0 +1,91 @@
+<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>parent-boot-performance</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>parent-boot-performance</name>
+    <packaging>pom</packaging>
+    <description>Parent for all modules that want to take advantage of the latest Spring Boot improvements/features. Current version: 2.2</description>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <properties>
+        <rest-assured.version>3.1.0</rest-assured.version>
+        <!-- plugins -->
+        <thin.version>1.0.21.RELEASE</thin.version>
+        <spring-boot.version>2.2.0.M3</spring-boot.version>
+    </properties>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-dependencies</artifactId>
+                <version>${spring-boot.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+    <dependencies>
+        <dependency>
+            <groupId>io.rest-assured</groupId>
+            <artifactId>rest-assured</artifactId>
+            </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.springframework.boot</groupId>
+                    <artifactId>spring-boot-maven-plugin</artifactId>
+                    <version>${spring-boot.version}</version>
+                    <configuration>
+                        <mainClass>${start-class}</mainClass>
+                        <!-- this is necessary as we're not using the Boot parent -->
+                    </configuration>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+    
+    <repositories>
+        <repository>
+            <id>spring-milestones</id>
+            <name>Spring Milestones</name>
+            <url>https://repo.spring.io/milestone</url>
+        </repository>
+    </repositories>
+    
+    <profiles>
+        <profile>
+            <id>thin-jar</id>
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>org.springframework.boot</groupId>
+                        <artifactId>spring-boot-maven-plugin</artifactId>
+                        <dependencies>
+                            <!-- The following enables the "thin jar" deployment option. -->
+                            <dependency>
+                                <groupId>org.springframework.boot.experimental</groupId>
+                                <artifactId>spring-boot-thin-layout</artifactId>
+                                <version>${thin.version}</version>
+                            </dependency>
+                        </dependencies>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+    </profiles>
+</project>

persistence-modules/java-jpa/pom.xml

@@ -19,6 +19,11 @@
             <artifactId>hibernate-core</artifactId>
             <version>${hibernate.version}</version>
         </dependency>
+		<dependency>
+			<groupId>org.hibernate</groupId>
+			<artifactId>hibernate-jpamodelgen</artifactId>
+			<version>${hibernate.version}</version>
+		</dependency>
         <dependency>
             <groupId>com.h2database</groupId>
             <artifactId>h2</artifactId>
@@ -47,6 +52,58 @@
         </dependency>
     </dependencies>
 
+	<build>
+		<plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.5.1</version>
+                <configuration>
+                    <compilerArgument>-proc:none</compilerArgument>
+                </configuration>
+            </plugin>
+			<plugin>
+				<groupId>org.bsc.maven</groupId>
+				<artifactId>maven-processor-plugin</artifactId>
+				<version>3.3.3</version>
+				<executions>
+					<execution>
+						<id>process</id>
+						<goals>
+							<goal>process</goal>
+						</goals>
+						<phase>generate-sources</phase>
+						<configuration>
+							<outputDirectory>target/metamodel</outputDirectory>
+							<processors>
+								<processor>org.hibernate.jpamodelgen.JPAMetaModelEntityProcessor</processor>
+							</processors>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+
+			<plugin>
+				<groupId>org.codehaus.mojo</groupId>
+				<artifactId>build-helper-maven-plugin</artifactId>
+				<version>3.0.0</version>
+				<executions>
+					<execution>
+						<id>add-source</id>
+						<phase>generate-sources</phase>
+						<goals>
+							<goal>add-source</goal>
+						</goals>
+						<configuration>
+							<sources>
+								<source>target/metamodel</source>
+							</sources>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
     <properties>
         <hibernate.version>5.4.0.Final</hibernate.version>
         <eclipselink.version>2.7.4-RC1</eclipselink.version>

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/queryparams/Employee.java

@@ -0,0 +1,79 @@
+package com.baeldung.jpa.queryparams;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "employees")
+public class Employee {
+
+    /**
+     * 
+     */
+    private static final long serialVersionUID = 1L;
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(name = "id")
+    private Long id;
+
+    @Column(name = "employee_number", unique = true)
+    private String empNumber;
+
+    @Column(name = "employee_name")
+    private String name;
+
+    @Column(name = "employee_age")
+    private int age;
+
+    public Employee() {
+        super();
+    }
+
+    public Employee(Long id, String empNumber) {
+        super();
+        this.id = id;
+        this.empNumber = empNumber;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getEmpNumber() {
+        return empNumber;
+    }
+
+    public void setEmpNumber(String empNumber) {
+        this.empNumber = empNumber;
+    }
+
+    public static long getSerialversionuid() {
+        return serialVersionUID;
+    }
+
+}

persistence-modules/java-jpa/src/main/resources/META-INF/persistence.xml

@@ -224,4 +224,26 @@
 				value="products_jpa.sql" />
 		</properties>
 	</persistence-unit>
+	
+	<persistence-unit name="jpa-h2-queryparams" transaction-type="RESOURCE_LOCAL">
+		<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
+		<class>com.baeldung.jpa.queryparams.Employee</class>
+		<exclude-unlisted-classes>true</exclude-unlisted-classes>
+		<properties>
+			<property name="javax.persistence.jdbc.driver"
+				value="org.h2.Driver" />
+			<property name="javax.persistence.jdbc.url"
+				value="jdbc:h2:mem:test" />
+			<property name="javax.persistence.jdbc.user" value="sa" />
+			<property name="javax.persistence.jdbc.password" value="" />
+			<property name="hibernate.dialect"
+				value="org.hibernate.dialect.H2Dialect" />
+			<property name="hibernate.hbm2ddl.auto" value="create-drop" />
+			<property name="show_sql" value="true" />
+			<property name="hibernate.temp.use_jdbc_metadata_defaults"
+				value="false" />
+			<property name="javax.persistence.sql-load-script-source"
+				value="employees2.sql" />
+		</properties>
+	</persistence-unit>
 </persistence>

persistence-modules/java-jpa/src/test/java/com/baeldung/jpa/queryparams/JPAQueryParamsUnitTest.java

@@ -0,0 +1,109 @@
+package com.baeldung.jpa.queryparams;
+
+import java.util.Arrays;
+import java.util.List;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+import javax.persistence.TypedQuery;
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.ParameterExpression;
+import javax.persistence.criteria.Root;
+
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+/**
+ * JPAQueryParamsTest class tests.
+ *
+ * @author gmlopez.mackinnon@gmail.com
+ */
+public class JPAQueryParamsUnitTest {
+
+    private static EntityManager entityManager;
+
+    @BeforeClass
+    public static void setup() {
+        EntityManagerFactory factory = Persistence.createEntityManagerFactory("jpa-h2-queryparams");
+        entityManager = factory.createEntityManager();
+    }
+
+    @Test
+    public void givenEmpNumber_whenUsingPositionalParameter_thenReturnExpectedEmployee() {
+        TypedQuery<Employee> query = entityManager.createQuery("SELECT e FROM Employee e WHERE e.empNumber = ?1", Employee.class);
+        String empNumber = "A123";
+        Employee employee = query.setParameter(1, empNumber)
+            .getSingleResult();
+        Assert.assertNotNull("Employee not found", employee);
+    }
+
+    @Test
+    public void givenEmpNumberList_whenUsingPositionalParameter_thenReturnExpectedEmployee() {
+        TypedQuery<Employee> query = entityManager.createQuery("SELECT e FROM Employee e WHERE e.empNumber IN (?1)", Employee.class);
+        List<String> empNumbers = Arrays.asList("A123", "A124");
+        List<Employee> employees = query.setParameter(1, empNumbers)
+            .getResultList();
+        Assert.assertNotNull("Employees not found", employees);
+        Assert.assertFalse("Employees not found", employees.isEmpty());
+    }
+
+    @Test
+    public void givenEmpNumber_whenUsingNamedParameter_thenReturnExpectedEmployee() {
+        TypedQuery<Employee> query = entityManager.createQuery("SELECT e FROM Employee e WHERE e.empNumber = :number", Employee.class);
+        String empNumber = "A123";
+        Employee employee = query.setParameter("number", empNumber)
+            .getSingleResult();
+        Assert.assertNotNull("Employee not found", employee);
+    }
+
+    @Test
+    public void givenEmpNumberList_whenUsingNamedParameter_thenReturnExpectedEmployee() {
+        TypedQuery<Employee> query = entityManager.createQuery("SELECT e FROM Employee e WHERE e.empNumber IN (:numbers)", Employee.class);
+        List<String> empNumbers = Arrays.asList("A123", "A124");
+        List<Employee> employees = query.setParameter("numbers", empNumbers)
+            .getResultList();
+        Assert.assertNotNull("Employees not found", employees);
+        Assert.assertFalse("Employees not found", employees.isEmpty());
+    }
+
+    @Test
+    public void givenEmpNameAndEmpAge_whenUsingTwoNamedParameters_thenReturnExpectedEmployees() {
+        TypedQuery<Employee> query = entityManager.createQuery("SELECT e FROM Employee e WHERE e.name = :name AND e.age = :empAge", Employee.class);
+        String empName = "John Doe";
+        int empAge = 55;
+        List<Employee> employees = query.setParameter("name", empName)
+            .setParameter("empAge", empAge)
+            .getResultList();
+        Assert.assertNotNull("Employees not found!", employees);
+        Assert.assertTrue("Employees not found!", !employees.isEmpty());
+    }
+
+    @Test
+    public void givenEmpNumber_whenUsingCriteriaQuery_thenReturnExpectedEmployee() {
+        CriteriaBuilder cb = entityManager.getCriteriaBuilder();
+
+        CriteriaQuery<Employee> cQuery = cb.createQuery(Employee.class);
+        Root<Employee> c = cQuery.from(Employee.class);
+        ParameterExpression<String> paramEmpNumber = cb.parameter(String.class);
+        cQuery.select(c)
+            .where(cb.equal(c.get(Employee_.empNumber), paramEmpNumber));
+
+        TypedQuery<Employee> query = entityManager.createQuery(cQuery);
+        String empNumber = "A123";
+        query.setParameter(paramEmpNumber, empNumber);
+        Employee employee = query.getSingleResult();
+        Assert.assertNotNull("Employee not found!", employee);
+    }
+
+    @Test
+    public void givenEmpNumber_whenUsingLiteral_thenReturnExpectedEmployee() {
+        String empNumber = "A123";
+        TypedQuery<Employee> query = entityManager.createQuery("SELECT e FROM Employee e WHERE e.empNumber = '" + empNumber + "'", Employee.class);
+        Employee employee = query.getSingleResult();
+        Assert.assertNotNull("Employee not found!", employee);
+    }
+
+}

persistence-modules/java-jpa/src/test/resources/employees2.sql

@@ -0,0 +1,2 @@
+INSERT INTO employees (employee_number, employee_name, employee_age) VALUES ('111', 'John Doe', 55);
+INSERT INTO employees (employee_number, employee_name, employee_age) VALUES ('A123', 'John Doe Junior', 25);

ratpack/build.gradle

@@ -14,6 +14,8 @@ if (!JavaVersion.current().java8Compatible) {
 
 apply plugin: "io.ratpack.ratpack-java"
 apply plugin: 'java'
+apply plugin: 'groovy'
+apply plugin: 'io.ratpack.ratpack-groovy'
 
 repositories {
   jcenter()

ratpack/pom.xml

@@ -26,11 +26,21 @@
             <artifactId>ratpack-core</artifactId>
             <version>${ratpack.version}</version>
         </dependency>
+        <dependency>
+    		<groupId>org.codehaus.groovy</groupId>
+		    <artifactId>groovy-sql</artifactId>
+		    <version>${groovy.sql.version}</version>
+		</dependency>
         <dependency>
             <groupId>io.ratpack</groupId>
             <artifactId>ratpack-hikari</artifactId>
             <version>${ratpack.version}</version>
         </dependency>
+        <dependency>
+        	<groupId>io.ratpack</groupId>
+            <artifactId>ratpack-groovy-test</artifactId>
+            <version>${ratpack.test.latest.version}</version>
+        </dependency>
         <dependency>
             <groupId>io.ratpack</groupId>
             <artifactId>ratpack-hystrix</artifactId>
@@ -91,6 +101,7 @@
         <httpclient.version>4.5.3</httpclient.version>
         <httpcore.version>4.4.6</httpcore.version>
         <hystrix.version>1.5.12</hystrix.version>
+        <groovy.sql.version>2.4.15</groovy.sql.version>
+        <ratpack.test.latest.version>1.6.1</ratpack.test.latest.version>
     </properties>
-
 </project>

ratpack/src/main/groovy/com/baeldung/Ratpack.groovy

@@ -0,0 +1,76 @@
+package com.baeldung;
+
+@Grab('io.ratpack:ratpack-groovy:1.6.1')
+import static ratpack.groovy.Groovy.ratpack
+
+import com.baeldung.model.User
+import com.google.common.reflect.TypeToken
+import ratpack.exec.Promise
+import ratpack.handling.Context
+import ratpack.jackson.Jackson
+import groovy.sql.Sql
+import java.sql.Connection
+import java.sql.PreparedStatement
+import java.sql.ResultSet
+import ratpack.hikari.HikariModule
+import javax.sql.DataSource;
+
+ratpack {
+    serverConfig { port(5050) }
+    bindings {
+        module(HikariModule) { config ->
+            config.dataSourceClassName = 'org.h2.jdbcx.JdbcDataSource'
+            config.addDataSourceProperty('URL', "jdbc:h2:mem:devDB;INIT=RUNSCRIPT FROM 'classpath:/User.sql'")
+        }
+    }
+
+    handlers {
+
+        get { render 'Hello World from Ratpack with Groovy!!' }
+
+        get("greet/:name") { Context ctx ->
+            render "Hello " + ctx.getPathTokens().get("name") + "!!!"
+        }
+
+        get("data") {
+            render Jackson.json([title: "Mr", name: "Norman", country: "USA"])
+        }
+
+        post("user") {
+            Promise<User> user = parse(Jackson.fromJson(User))
+            user.then { u -> render u.name }
+        }
+
+        get('fetchUserName/:id') { Context ctx ->
+            Connection connection = ctx.get(DataSource.class).getConnection()
+            PreparedStatement queryStatement = connection.prepareStatement("SELECT NAME FROM USER WHERE ID=?")
+            queryStatement.setInt(1, Integer.parseInt(ctx.getPathTokens().get("id")))
+            ResultSet resultSet = queryStatement.executeQuery()
+            resultSet.next()
+            render resultSet.getString(1)
+        }
+
+        get('fetchUsers') {
+            def db = [url:'jdbc:h2:mem:devDB']
+            def sql = Sql.newInstance(db.url, db.user, db.password)
+            def users = sql.rows("SELECT * FROM USER");
+            render(Jackson.json(users))
+        }
+
+        post('addUser') {
+            parse(Jackson.fromJson(User))
+                .then { u ->
+                    def db = [url:'jdbc:h2:mem:devDB']
+                    Sql sql = Sql.newInstance(db.url, db.user, db.password)
+                    sql.executeInsert("INSERT INTO USER VALUES (?,?,?,?)", [
+                        u.id,
+                        u.title,
+                        u.name,
+                        u.country
+                    ])
+                    render "User $u.name inserted"
+                }
+        }
+    }
+}
+

ratpack/src/main/groovy/com/baeldung/RatpackGroovyApp.groovy

@@ -0,0 +1,12 @@
+package com.baeldung;
+
+public class RatpackGroovyApp {
+
+    public static void main(String[] args) {
+        File file = new File("src/main/groovy/com/baeldung/Ratpack.groovy");
+        def shell = new GroovyShell()  
+        shell.evaluate(file)
+    }
+    
+}
+

ratpack/src/main/groovy/com/baeldung/model/User.groovy

@@ -0,0 +1,9 @@
+package com.baeldung.model
+
+class User {
+    
+    long id
+    String title
+    String name
+    String country
+}

ratpack/src/main/resources/User.sql

@@ -0,0 +1,10 @@
+DROP TABLE IF EXISTS USER;
+CREATE TABLE USER (
+  ID BIGINT AUTO_INCREMENT PRIMARY KEY,
+  TITLE VARCHAR(255),
+  NAME VARCHAR(255),
+  COUNTRY VARCHAR(255)
+);
+
+INSERT INTO USER VALUES(1,'Mr','Norman Potter', 'USA');
+INSERT INTO USER VALUES(2,'Miss','Ketty Smith', 'FRANCE');

ratpack/src/test/groovy/com/baeldung/RatpackGroovySpec.groovy

@@ -0,0 +1,46 @@
+package com.baeldung;
+
+import ratpack.groovy.Groovy
+import ratpack.groovy.test.GroovyRatpackMainApplicationUnderTest;
+import ratpack.test.http.TestHttpClient;
+import ratpack.test.ServerBackedApplicationUnderTest;
+import org.junit.Test;
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+import ratpack.test.MainClassApplicationUnderTest
+
+class RatpackGroovySpec {
+
+    ServerBackedApplicationUnderTest ratpackGroovyApp = new MainClassApplicationUnderTest(RatpackGroovyApp.class)
+    @Delegate TestHttpClient client = TestHttpClient.testHttpClient(ratpackGroovyApp)
+
+    @Test
+    void "test if app is started"() {
+        when:
+        get("")
+
+        then:
+        assert response.statusCode == 200
+        assert response.body.text == "Hello World from Ratpack with Groovy!!"
+    }
+
+    @Test
+    void "test greet with name"() {
+        when:
+        get("greet/Lewis")
+
+        then:
+        assert response.statusCode == 200
+        assert response.body.text == "Hello Lewis!!!"
+    }
+
+    @Test
+    void "test fetchUsers"() {
+        when:
+        get("fetchUsers")
+
+        then:
+        assert response.statusCode == 200
+        assert response.body.text == '[{"ID":1,"TITLE":"Mr","NAME":"Norman Potter","COUNTRY":"USA"},{"ID":2,"TITLE":"Miss","NAME":"Ketty Smith","COUNTRY":"FRANCE"}]'
+    }
+}

spring-boot-performance/pom.xml

@@ -0,0 +1,45 @@
+<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>spring-boot-performance</artifactId>
+    <name>spring-boot-performance</name>
+    <packaging>war</packaging>
+    <description>This is a simple Spring Boot application taking advantage of the latest Spring Boot improvements/features. Current version: 2.2</description>
+
+    <parent>
+        <artifactId>parent-boot-performance</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-boot-performance</relativePath>
+    </parent>
+
+    <properties>
+        <!-- The main class to start by executing java -jar -->
+        <start-class>com.baeldung.lazyinitialization.Application</start-class>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter</artifactId>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>spring-boot-performance</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-war-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+</project>

spring-boot-performance/src/main/java/com/baeldung/lazyinitialization/Application.java

@@ -0,0 +1,32 @@
+package com.baeldung.lazyinitialization;
+
+import com.baeldung.lazyinitialization.services.Writer;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.Bean;
+
+@SpringBootApplication
+public class Application {
+
+    @Bean("writer1")
+    public Writer getWriter1() {
+        return new Writer("Writer 1");
+    }
+
+    @Bean("writer2")
+    public Writer getWriter2() {
+        return new Writer("Writer 2");
+    }
+
+    public static void main(String[] args) {
+        ApplicationContext ctx = SpringApplication.run(Application.class, args);
+        System.out.println("Application context initialized!!!");
+
+        Writer writer1 = ctx.getBean("writer1", Writer.class);
+        writer1.write("First message");
+
+        Writer writer2 = ctx.getBean("writer2", Writer.class);
+        writer2.write("Second message");
+    }
+}

spring-boot-performance/src/main/java/com/baeldung/lazyinitialization/services/Writer.java

@@ -0,0 +1,16 @@
+package com.baeldung.lazyinitialization.services;
+
+public class Writer {
+
+    private final String writerId;
+
+    public Writer(String writerId) {
+        this.writerId = writerId;
+        System.out.println(writerId + " initialized!!!");
+    }
+
+    public void write(String message) {
+        System.out.println(writerId + ": " + message);
+    }
+
+}

spring-boot-performance/src/main/resources/application.yml

@@ -0,0 +1,3 @@
+spring:
+  main:
+    lazy-initialization: true

spring-static-resources/pom.xml

@@ -141,6 +141,13 @@
             <version>${handlebars.version}</version>
         </dependency>
 
+        <!-- commons.io -->
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>${commons.io.version}</version>
+        </dependency>
+        
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-test</artifactId>
@@ -208,6 +215,9 @@
 
         <!-- Maven plugins -->
         <yuicompressor-maven-plugin.version>1.5.1</yuicompressor-maven-plugin.version>
+
+        <!-- commons.io -->
+        <commons.io.version>2.5</commons.io.version>
     </properties>
 
 </project>

spring-static-resources/src/main/java/com/baeldung/loadresourceasstring/LoadResourceConfig.java

@@ -0,0 +1,15 @@
+package com.baeldung.loadresourceasstring;
+
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class LoadResourceConfig {
+
+    @Bean
+    public String resourceString() {
+        return ResourceReader.readFileToString("resource.txt");
+    }
+
+}

spring-static-resources/src/main/java/com/baeldung/loadresourceasstring/ResourceReader.java

@@ -0,0 +1,30 @@
+package com.baeldung.loadresourceasstring;
+
+import org.springframework.core.io.DefaultResourceLoader;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.ResourceLoader;
+import org.springframework.util.FileCopyUtils;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.io.UncheckedIOException;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+
+public class ResourceReader {
+
+    public static String readFileToString(String path) {
+        ResourceLoader resourceLoader = new DefaultResourceLoader();
+        Resource resource = resourceLoader.getResource(path);
+        return asString(resource);
+    }
+
+    public static String asString(Resource resource) {
+        try (Reader reader = new InputStreamReader(resource.getInputStream(), UTF_8)) {
+            return FileCopyUtils.copyToString(reader);
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+}

spring-static-resources/src/main/resources/resource.txt

@@ -0,0 +1 @@
+This is a resource text file. This file will be loaded as a resource and use its contents as a string.

spring-static-resources/src/test/java/com/baeldung/loadresourceasstring/LoadResourceAsStringIntegrationTest.java

@@ -0,0 +1,57 @@
+package com.baeldung.loadresourceasstring;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.core.io.DefaultResourceLoader;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.ResourceLoader;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.support.AnnotationConfigContextLoader;
+import org.springframework.util.FileCopyUtils;
+
+import java.io.InputStreamReader;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.junit.Assert.assertEquals;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(loader = AnnotationConfigContextLoader.class, classes = LoadResourceConfig.class)
+public class LoadResourceAsStringIntegrationTest {
+
+    private static final String EXPECTED_RESOURCE_VALUE = "This is a resource text file. This file will be loaded as a " + "resource and use its contents as a string.";
+
+    @Value("#{T(com.baeldung.loadresourceasstring.ResourceReader).readFileToString('classpath:resource.txt')}")
+    private String resourceStringUsingSpel;
+
+    @Autowired
+    @Qualifier("resourceString")
+    private String resourceString;
+
+    @Autowired
+    private ResourceLoader resourceLoader;
+
+    @Test
+    public void givenUsingResourceLoadAndFileCopyUtils_whenConvertingAResourceToAString_thenCorrect() {
+        Resource resource = resourceLoader.getResource("classpath:resource.txt");
+        assertEquals(EXPECTED_RESOURCE_VALUE, ResourceReader.asString(resource));
+    }
+
+    @Test
+    public void givenUsingResourceStringBean_whenConvertingAResourceToAString_thenCorrect() {
+        assertEquals(EXPECTED_RESOURCE_VALUE, resourceString);
+    }
+
+    @Test
+    public void givenUsingSpel_whenConvertingAResourceToAString_thenCorrect() {
+        assertEquals(EXPECTED_RESOURCE_VALUE, resourceStringUsingSpel);
+    }
+
+
+
+
+}