merge remote

.gitignore

@@ -1,4 +1,5 @@
 */bin/*
+bin/
 
 *.class
 
@@ -21,6 +22,9 @@
 *.iws
 out/
 
+# VSCode
+.vscode/
+
 # Mac
 .DS_Store
 

algorithms-miscellaneous-3/README.md

@@ -6,4 +6,4 @@
 - [Practical Java Examples of the Big O Notation](http://www.baeldung.com/java-algorithm-complexity)
 - [Checking If a List Is Sorted in Java](https://www.baeldung.com/java-check-if-list-sorted)
 - [Checking if a Java Graph has a Cycle](https://www.baeldung.com/java-graph-has-a-cycle)
-- [A Guide to the Folding Technique](https://www.baeldung.com/folding-hashing-technique)
+- [A Guide to the Folding Technique in Java](https://www.baeldung.com/folding-hashing-technique)

apache-olingo/olingo2/pom.xml

@@ -9,12 +9,12 @@
 	<name>olingo2-sample</name>
 	<description>Sample Olingo 2 Project</description>
 
-	<parent>
-		<groupId>org.springframework.boot</groupId>
-		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>2.1.3.RELEASE</version>
-		<relativePath /> <!-- lookup parent from repository -->
-	</parent>
+    <parent>
+        <artifactId>parent-boot-2</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-boot-2</relativePath>
+    </parent>
 
 	<dependencies>
 		<dependency>
@@ -82,7 +82,6 @@
 	</build>
 
 	<properties>
-		<java.version>1.8</java.version>
 		<olingo2.version>2.0.11</olingo2.version>
 	</properties>
 

apache-olingo/olingo2/src/test/java/org/baeldung/examples/olingo2/Olingo2SampleApplicationUnitTest.java

@@ -7,7 +7,7 @@ import org.springframework.test.context.junit4.SpringRunner;
 
 @RunWith(SpringRunner.class)
 @SpringBootTest
-public class Olingo2SampleApplicationTests {
+public class Olingo2SampleApplicationUnitTest {
 
 	@Test
 	public void contextLoads() {

apache-pulsar/pom.xml

@@ -7,6 +7,13 @@
     <version>0.0.1</version>
     <name>apache-pulsar</name>
 
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>..</relativePath>
+    </parent>
+
     <dependencies>
         <dependency>
             <groupId>org.apache.pulsar</groupId>

apache-pulsar/src/main/java/com/baeldung/ConsumerUnitTest.java

@@ -7,7 +7,7 @@ import org.apache.pulsar.client.api.Message;
 import org.apache.pulsar.client.api.PulsarClient;
 import org.apache.pulsar.client.api.SubscriptionType;
 
-public class ConsumerTest {
+public class ConsumerUnitTest {
 
     private static final String SERVICE_URL = "pulsar://localhost:6650";
     private static final String TOPIC_NAME = "test-topic";

apache-pulsar/src/main/java/com/baeldung/ProducerUnitTest.java

@@ -11,7 +11,7 @@ import org.apache.pulsar.client.api.PulsarClientException;
 import java.io.IOException;
 import java.util.stream.IntStream;
 
-public class ProducerTest {
+public class ProducerUnitTest {
 
     private static final String SERVICE_URL = "pulsar://localhost:6650";
     private static final String TOPIC_NAME = "test-topic";

apache-pulsar/src/main/java/com/baeldung/subscriptions/ExclusiveSubscriptionUnitTest.java

@@ -10,7 +10,7 @@ import org.apache.pulsar.client.api.SubscriptionType;
 
 import java.util.stream.IntStream;
 
-public class ExclusiveSubscriptionTest {
+public class ExclusiveSubscriptionUnitTest {
     private static final String SERVICE_URL = "pulsar://localhost:6650";
     private static final String TOPIC_NAME = "test-topic";
     private static final String SUBSCRIPTION_NAME = "test-subscription";

apache-pulsar/src/main/java/com/baeldung/subscriptions/FailoverSubscriptionUnitTest.java

@@ -11,7 +11,7 @@ import org.apache.pulsar.client.api.SubscriptionType;
 
 import java.util.stream.IntStream;
 
-public class FailoverSubscriptionTest {
+public class FailoverSubscriptionUnitTest {
     private static final String SERVICE_URL = "pulsar://localhost:6650";
     private static final String TOPIC_NAME = "failover-subscription-test-topic";
     private static final String SUBSCRIPTION_NAME = "test-subscription";

aws/pom.xml

@@ -112,7 +112,6 @@
     </repositories>
 
     <properties>
-        <commons-io.version>2.5</commons-io.version>
         <aws-lambda-java-events.version>1.3.0</aws-lambda-java-events.version>
         <aws-lambda-java-core.version>1.1.0</aws-lambda-java-core.version>
         <gson.version>2.8.0</gson.version>

core-groovy-2/pom.xml

@@ -175,8 +175,6 @@
         <junit.platform.version>1.0.0</junit.platform.version>
         <hsqldb.version>2.4.0</hsqldb.version>
         <spock-core.version>1.1-groovy-2.4</spock-core.version>
-        <commons-lang3.version>3.9</commons-lang3.version>
-        <java.version>1.8</java.version>
         <maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
         <logback.version>1.2.3</logback.version>
         <groovy.version>2.5.7</groovy.version>

core-groovy-2/src/main/groovy/com/baeldung/concatenate/Wonder.groovy

@@ -0,0 +1,52 @@
+package com.baeldung.concatenate
+
+class Wonder {
+
+    String numOfWonder = 'seven'
+
+    String operator_plus() {
+        return 'The ' + numOfWonder + ' wonders of the world'
+    }
+
+    String operator_left() {
+        return 'The ' << numOfWonder << ' wonders of ' << 'the world'
+    }
+
+    String interpolation_one() {
+        return "The $numOfWonder wonders of the world"
+
+    }
+
+    String interpolation_two() {
+        return "The ${numOfWonder} wonders of the world"
+    }
+
+    String multilineString() {
+        return """
+            There are $numOfWonder wonders of the world.
+            Can you name them all? 
+            1. The Great Pyramid of Giza
+            2. Hanging Gardens of Babylon
+            3. Colossus of Rhode
+            4. Lighthouse of Alexendra
+            5. Temple of Artemis
+            6. Status of Zeus at Olympia
+            7. Mausoleum at Halicarnassus
+        """
+    }
+
+    String method_concat() {
+        return 'The '.concat(numOfWonder).concat(' wonders of the world')
+
+    }
+
+    String method_builder() {
+        return new StringBuilder()
+                .append('The ').append(numOfWonder).append(' wonders of the world')
+    }
+
+    String method_buffer() {
+        return new StringBuffer()
+                .append('The ').append(numOfWonder).append(' wonders of the world')
+    }
+}

core-groovy-2/src/test/groovy/com/baeldung/concatenate/WonderUnitTest.groovy

@@ -0,0 +1,69 @@
+package com.baeldung.concatenate
+
+import org.junit.Before
+import org.junit.Test
+
+import static org.junit.Assert.*
+
+class WonderUnitTest {
+
+    static final String EXPECTED_SINGLE_LINE = "The seven wonders of the world"
+
+    Wonder wonder
+
+    @Before
+    void before() {
+        wonder = new Wonder()
+    }
+
+    @Test
+    void whenUsingOperatorPlus_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.operator_plus())
+    }
+
+    @Test
+    void whenUsingOperatorLeft_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.operator_left())
+    }
+
+    @Test
+    void whenUsingInterpolationOne_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.interpolation_one())
+    }
+
+    @Test
+    void whenUsingInterpolationTwo_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.interpolation_two())
+    }
+
+    @Test
+    void whenUsingMultiline_thenConcatCorrectly() {
+        def expectedMultiline = """
+            There are seven wonders of the world.
+            Can you name them all? 
+            1. The Great Pyramid of Giza
+            2. Hanging Gardens of Babylon
+            3. Colossus of Rhode
+            4. Lighthouse of Alexendra
+            5. Temple of Artemis
+            6. Status of Zeus at Olympia
+            7. Mausoleum at Halicarnassus
+        """
+        assertEquals(expectedMultiline, wonder.multilineString())
+    }
+
+    @Test
+    void whenUsingMethodConcat_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.method_concat())
+    }
+
+    @Test
+    void whenUsingMethodBuilder_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.method_builder())
+    }
+
+    @Test
+    void whenUsingMethodBuffer_thenConcatCorrectly() {
+        assertEquals(EXPECTED_SINGLE_LINE, wonder.method_buffer())
+    }
+}

core-java-modules/core-java-11/src/main/java/com/baeldung/predicate/not/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Negate a Predicate Method Reference with Java 11](https://www.baeldung.com/java-negate-predicate-method-reference)

core-java-modules/core-java-12/README.md

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [String API Updates in Java 12](https://www.baeldung.com/java12-string-api)

core-java-modules/core-java-8/pom.xml

@@ -175,7 +175,6 @@
 
     <properties>
         <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-math3.version>3.6.1</commons-math3.version>
         <commons-collections4.version>4.1</commons-collections4.version>
         <collections-generic.version>4.01</collections-generic.version>

core-java-modules/core-java-8/src/test/java/com/baeldung/java8/optional/OptionalUnitTest.java

@@ -259,4 +259,15 @@ public class OptionalUnitTest {
         LOG.debug("Getting default value...");
         return "Default Value";
     }
+    
+//    Uncomment code when code base is compatiable with Java 11     
+//    @Test
+//    public void givenAnEmptyOptional_thenIsEmptyBehavesAsExpected() {
+//        Optional<String> opt = Optional.of("Baeldung");
+//        assertFalse(opt.isEmpty());
+//     
+//        opt = Optional.ofNullable(null);
+//        assertTrue(opt.isEmpty());
+//    }
+
 }

core-java-modules/core-java-arrays/src/main/java/com/baeldung/array/SortedArrayChecker.java

@@ -0,0 +1,71 @@
+package com.baeldung.array;
+
+import com.baeldung.arraycopy.model.Employee;
+
+public class SortedArrayChecker {
+    boolean isSorted(int[] array, int length) {
+        if (array == null || length < 2)
+            return true;
+
+        if (array[length - 2] > array[length - 1])
+            return false;
+
+        return isSorted(array, length - 1);
+    }
+
+    boolean isSorted(int[] array) {
+        for (int i = 0; i < array.length - 1; i++) {
+            if (array[i] > array[i + 1])
+                return false;
+        }
+
+        return true;
+    }
+
+    boolean isSorted(String[] array, int length) {
+        if (array == null || length < 2)
+            return true;
+
+        if (array[length - 2].compareTo(array[length - 1]) > 0)
+            return false;
+
+        return isSorted(array, length - 1);
+    }
+
+boolean isSorted(String[] array) {
+    for (int i = 0; i < array.length - 1; ++i) {
+        if (array[i].compareTo(array[i + 1]) > 0)
+            return false;
+    }
+
+    return true;
+}
+
+    boolean isSortedByName(Employee[] array) {
+        for (int i = 0; i < array.length - 1; ++i) {
+            if (array[i].getName().compareTo(array[i + 1].getName()) > 0)
+                return false;
+        }
+
+        return true;
+    }
+
+boolean isSortedByAge(Employee[] array) {
+    for (int i = 0; i < array.length - 1; ++i) {
+        if (array[i].getAge() > (array[i + 1].getAge()))
+            return false;
+    }
+
+    return true;
+}
+
+    boolean isSortedByAge(Employee[] array, int length) {
+        if (array == null || length < 2)
+            return true;
+
+        if (array[length - 2].getAge() > array[length - 1].getAge())
+            return false;
+
+        return isSortedByAge(array, length - 1);
+    }
+}

core-java-modules/core-java-arrays/src/main/java/com/baeldung/arraycopy/model/Employee.java

@@ -6,6 +6,7 @@ public class Employee implements Serializable {
     private static final long serialVersionUID = -2454619097207585825L;
     private int id;
     private String name;
+    private int age;
 
     public Employee() {
     }
@@ -15,10 +16,24 @@ public class Employee implements Serializable {
         this.name = name;
     }
 
+    public Employee(int id, String name, int age) {
+        this.id = id;
+        this.name = name;
+        this.age = age;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
     public int getId() {
         return id;
     }
 
+    public void setAge(int age) {
+        this.age = age;
+    }
+
     public void setId(int id) {
         this.id = id;
     }

core-java-modules/core-java-arrays/src/test/java/com/baeldung/array/SortedArrayCheckerUnitTest.java

@@ -0,0 +1,73 @@
+package com.baeldung.array;
+
+import com.baeldung.arraycopy.model.Employee;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class SortedArrayCheckerUnitTest {
+
+    private static final int[] INTEGER_SORTED = {1, 3, 5, 7, 9};
+    private static final int[] INTEGER_NOT_SORTED = {1, 3, 11, 7};
+
+    private static final String[] STRING_SORTED = {"abc", "cde", "fgh"};
+    private static final String[] STRING_NOT_SORTED = {"abc", "fgh", "cde", "ijk"};
+
+    private final Employee[] EMPLOYEES_SORTED_BY_NAME = {
+            new Employee(1, "Carlos", 26),
+            new Employee(2, "Daniel", 31),
+            new Employee(3, "Marta", 27)};
+
+    private final Employee[] EMPLOYEES_NOT_SORTED_BY_NAME = {
+            new Employee(1, "Daniel", 31),
+            new Employee(2, "Carlos", 26),
+            new Employee(3, "Marta", 27)};
+
+    private final Employee[] EMPLOYEES_SORTED_BY_AGE = {
+            new Employee(1, "Carlos", 26),
+            new Employee(2, "Marta", 27),
+            new Employee(3, "Daniel", 31)};
+
+    private final Employee[] EMPLOYEES_NOT_SORTED_BY_AGE = {
+            new Employee(1, "Marta", 27),
+            new Employee(2, "Carlos", 26),
+            new Employee(3, "Daniel", 31)};
+
+    private SortedArrayChecker sortedArrayChecker;
+
+    @Before
+    public void setup() {
+        sortedArrayChecker = new SortedArrayChecker();
+    }
+
+    @Test
+    public void givenIntegerArray_thenReturnIfItIsSortedOrNot() {
+        assertThat(sortedArrayChecker.isSorted(INTEGER_SORTED)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSorted(INTEGER_NOT_SORTED)).isEqualTo(false);
+
+        assertThat(sortedArrayChecker.isSorted(INTEGER_SORTED, INTEGER_SORTED.length)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSorted(INTEGER_NOT_SORTED, INTEGER_NOT_SORTED.length)).isEqualTo(false);
+    }
+
+    @Test
+    public void givenStringArray_thenReturnIfItIsSortedOrNot() {
+        assertThat(sortedArrayChecker.isSorted(STRING_SORTED)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSorted(STRING_NOT_SORTED)).isEqualTo(false);
+
+        assertThat(sortedArrayChecker.isSorted(STRING_SORTED, STRING_SORTED.length)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSorted(STRING_NOT_SORTED, STRING_NOT_SORTED.length)).isEqualTo(false);
+    }
+
+    @Test
+    public void givenEmployeeArray_thenReturnIfItIsSortedOrNot() {
+        assertThat(sortedArrayChecker.isSortedByName(EMPLOYEES_SORTED_BY_NAME)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSortedByName(EMPLOYEES_NOT_SORTED_BY_NAME)).isEqualTo(false);
+
+        assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_SORTED_BY_AGE)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_NOT_SORTED_BY_AGE)).isEqualTo(false);
+
+        assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_SORTED_BY_AGE, EMPLOYEES_SORTED_BY_AGE.length)).isEqualTo(true);
+        assertThat(sortedArrayChecker.isSortedByAge(EMPLOYEES_NOT_SORTED_BY_AGE, EMPLOYEES_NOT_SORTED_BY_AGE.length)).isEqualTo(false);
+    }
+}

core-java-modules/core-java-collections-array-list/src/test/java/org/baeldung/java/collections/CoreJavaCollectionsUnitTest.java

@@ -42,7 +42,7 @@ public class CoreJavaCollectionsUnitTest {
     @Test(expected = UnsupportedOperationException.class)
     public final void givenUsingGuavaBuilder_whenUnmodifiableListIsCreatedFromOriginal_thenNoLongerModifiable() {
         final List<String> list = new ArrayList<String>(Arrays.asList("one", "two", "three"));
-        final ImmutableList<Object> unmodifiableList = ImmutableList.builder().addAll(list).build();
+        final ImmutableList<String> unmodifiableList = ImmutableList.<String>builder().addAll(list).build();
         unmodifiableList.add("four");
     }
 

core-java-modules/core-java-concurrency-advanced/pom.xml

@@ -72,7 +72,6 @@
     <properties>
         <!-- util -->
         <guava.version>21.0</guava.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-math3.version>3.6.1</commons-math3.version>
         <commons-collections4.version>4.1</commons-collections4.version>
         <collections-generic.version>4.01</collections-generic.version>

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

@@ -17,3 +17,4 @@
 - [Runnable vs. Callable in Java](http://www.baeldung.com/java-runnable-callable)
 - [What is Thread-Safety and How to Achieve it?](https://www.baeldung.com/java-thread-safety)
 - [How to Start a Thread in Java](https://www.baeldung.com/java-start-thread)
+- [How to Delay Code Execution in Java](https://www.baeldung.com/java-delay-code-execution)

core-java-modules/core-java-concurrency-basic/pom.xml

@@ -45,8 +45,6 @@
     </build>
 
     <properties>
-        <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>
         <avaitility.version>1.7.0</avaitility.version>

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

@@ -62,7 +62,6 @@
     <properties>
         <!-- util -->
         <guava.version>21.0</guava.version>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <commons-math3.version>3.6.1</commons-math3.version>
         <commons-collections4.version>4.1</commons-collections4.version>
         <collections-generic.version>4.01</collections-generic.version>

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

@@ -0,0 +1,3 @@
+## Relevant articles:
+
+- [Will an Error Be Caught by Catch Block in Java?](https://www.baeldung.com/java-error-catch)

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

@@ -266,8 +266,7 @@
     <properties>
 
         <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
-        <bouncycastle.version>1.60</bouncycastle.version>
+        <bouncycastle.version>1.55</bouncycastle.version>
         <commons-codec.version>1.10</commons-codec.version>
         <commons-math3.version>3.6.1</commons-math3.version>
         <decimal4j.version>1.0.3</decimal4j.version>
@@ -283,7 +282,7 @@
         <!-- sftp -->
         <jsch.version>0.1.55</jsch.version>
         <sshj.version>0.27.0</sshj.version>
-        <vfs.version>2.3</vfs.version>        
+        <vfs.version>2.4</vfs.version>        
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>
         <avaitility.version>1.7.0</avaitility.version>

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

@@ -35,7 +35,6 @@
     </dependencies>
 
     <properties>
-        <commons-lang3.version>3.5</commons-lang3.version>
         <assertj.version>3.6.1</assertj.version>
     </properties>
 </project>

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

@@ -0,0 +1,3 @@
+## 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/pom.xml

@@ -75,13 +75,7 @@
     </build>
 
     <properties>
-        
-        <!-- marshalling -->
-        <jackson.version>2.8.5</jackson.version>
         <gson.version>2.8.2</gson.version>
-
-        <!-- util -->
-        <commons-lang3.version>3.5</commons-lang3.version>
         <!-- testing -->
         <assertj-core.version>3.10.0</assertj-core.version>
         <equalsverifier.version>3.0.3</equalsverifier.version>