Merge branch 'master' of https://github.com/eugenp/tutorials into BAEL-2221

core-java-8/findItemsBasedOnValues/.gitignore

@@ -1 +0,0 @@
-/bin/

core-java-collections/src/test/java/com/baeldung/findItems/FindItemsBasedOnOtherStreamUnitTest.java

@@ -1,93 +1,89 @@
-package findItems;
-
-import static org.junit.Assert.assertEquals;
-
-import java.text.ParseException;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-import java.util.stream.Collectors;
-
-import org.junit.Test;
-
-public class FindItemsBasedOnValues {
-
-    List<Employee> EmplList = new ArrayList<Employee>();
-    List<Department> deptList = new ArrayList<Department>();
-
-    public static void main(String[] args) throws ParseException {
-        FindItemsBasedOnValues findItems = new FindItemsBasedOnValues();
-        findItems.givenDepartmentList_thenEmployeeListIsFilteredCorrectly();
-    }
-
-    @Test
-    public void givenDepartmentList_thenEmployeeListIsFilteredCorrectly() {
-        Integer expectedId = 1002;
-
-        populate(EmplList, deptList);
-
-        List<Employee> filteredList = EmplList.stream()
-            .filter(empl -> deptList.stream()
-                .anyMatch(dept -> dept.getDepartment()
-                    .equals("sales") && empl.getEmployeeId()
-                    .equals(dept.getEmployeeId())))
-            .collect(Collectors.toList());
-
-        assertEquals(expectedId, filteredList.get(0)
-            .getEmployeeId());
-    }
-
-    private void populate(List<Employee> EmplList, List<Department> deptList) {
-        Employee employee1 = new Employee(1001, "empl1");
-        Employee employee2 = new Employee(1002, "empl2");
-        Employee employee3 = new Employee(1003, "empl3");
-
-        Collections.addAll(EmplList, employee1, employee2, employee3);
-
-        Department department1 = new Department(1002, "sales");
-        Department department2 = new Department(1003, "marketing");
-        Department department3 = new Department(1004, "sales");
-
-        Collections.addAll(deptList, department1, department2, department3);
-    }
-}
-
-class Employee {
-    Integer employeeId;
-    String employeeName;
-
-    public Employee(Integer employeeId, String employeeName) {
-        super();
-        this.employeeId = employeeId;
-        this.employeeName = employeeName;
-    }
-
-    public Integer getEmployeeId() {
-        return employeeId;
-    }
-
-    public String getEmployeeName() {
-        return employeeName;
-    }
-
-}
-
-class Department {
-    Integer employeeId;
-    String department;
-
-    public Department(Integer employeeId, String department) {
-        super();
-        this.employeeId = employeeId;
-        this.department = department;
-    }
-
-    public Integer getEmployeeId() {
-        return employeeId;
-    }
-
-    public String getDepartment() {
-        return department;
-    }
-
+package com.baeldung.findItems;
+
+import static org.junit.Assert.assertEquals;
+
+import java.text.ParseException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.junit.Test;
+
+public class FindItemsBasedOnOtherStreamUnitTest {
+
+    private List<Employee> employeeList = new ArrayList<Employee>();
+
+    private List<Department> departmentList = new ArrayList<Department>();
+
+    @Test
+    public void givenDepartmentList_thenEmployeeListIsFilteredCorrectly() {
+        Integer expectedId = 1002;
+
+        populate(employeeList, departmentList);
+
+        List<Employee> filteredList = employeeList.stream()
+            .filter(empl -> departmentList.stream()
+                .anyMatch(dept -> dept.getDepartment()
+                    .equals("sales") && empl.getEmployeeId()
+                    .equals(dept.getEmployeeId())))
+            .collect(Collectors.toList());
+
+        assertEquals(expectedId, filteredList.get(0)
+            .getEmployeeId());
+    }
+
+    private void populate(List<Employee> EmplList, List<Department> deptList) {
+        Employee employee1 = new Employee(1001, "empl1");
+        Employee employee2 = new Employee(1002, "empl2");
+        Employee employee3 = new Employee(1003, "empl3");
+
+        Collections.addAll(EmplList, employee1, employee2, employee3);
+
+        Department department1 = new Department(1002, "sales");
+        Department department2 = new Department(1003, "marketing");
+        Department department3 = new Department(1004, "sales");
+
+        Collections.addAll(deptList, department1, department2, department3);
+    }
+}
+
+class Employee {
+    private Integer employeeId;
+    private String employeeName;
+
+    Employee(Integer employeeId, String employeeName) {
+        super();
+        this.employeeId = employeeId;
+        this.employeeName = employeeName;
+    }
+
+    Integer getEmployeeId() {
+        return employeeId;
+    }
+
+    public String getEmployeeName() {
+        return employeeName;
+    }
+
+}
+
+class Department {
+    private Integer employeeId;
+    private String department;
+
+    Department(Integer employeeId, String department) {
+        super();
+        this.employeeId = employeeId;
+        this.department = department;
+    }
+
+    Integer getEmployeeId() {
+        return employeeId;
+    }
+
+    String getDepartment() {
+        return department;
+    }
+
 }

core-java-concurrency/src/test/java/com/baeldung/completablefuture/CompletableFutureLongRunningUnitTest.java

@@ -184,5 +184,25 @@ public class CompletableFutureLongRunningUnitTest {
 
         assertEquals("Hello World", future.get());
     }
+    
+    @Test
+    public void whenPassingTransformation_thenFunctionExecutionWithThenApply() throws InterruptedException, ExecutionException {
+        CompletableFuture<Integer> finalResult = compute().thenApply(s -> s + 1);
+        assertTrue(finalResult.get() == 11);
+    }
+    
+    @Test
+    public void whenPassingPreviousStage_thenFunctionExecutionWithThenCompose() throws InterruptedException, ExecutionException {
+        CompletableFuture<Integer> finalResult = compute().thenCompose(this::computeAnother);
+        assertTrue(finalResult.get() == 20);
+    }
+    
+    public CompletableFuture<Integer> compute(){
+        return CompletableFuture.supplyAsync(() -> 10);
+    }
+    
+    public CompletableFuture<Integer> computeAnother(Integer i){
+        return CompletableFuture.supplyAsync(() -> 10 + i);
+    }
 
 }

core-java/src/main/java/com/baeldung/array/ArrayReferenceGuide.java

@@ -0,0 +1,159 @@
+package com.baeldung.array;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+
+public class ArrayReferenceGuide {
+
+    public static void main(String[] args) {
+        declaration();
+
+        initialization();
+
+        access();
+
+        iterating();
+
+        varargs();
+
+        transformIntoList();
+
+        transformIntoStream();
+
+        sort();
+
+        search();
+
+        merge();
+    }
+
+    private static void declaration() {
+        int[] anArray;
+        int anotherArray[];
+    }
+
+    private static void initialization() {
+        int[] anArray = new int[10];
+        anArray[0] = 10;
+        anArray[5] = 4;
+
+        int[] anotherArray = new int[] {1, 2, 3, 4, 5};
+    }
+
+    private static void access() {
+        int[] anArray = new int[10];
+        anArray[0] = 10;
+        anArray[5] = 4;
+
+        System.out.println(anArray[0]);
+    }
+
+    private static void iterating() {
+        int[] anArray = new int[] {1, 2, 3, 4, 5};
+        for (int i = 0; i < anArray.length; i++) {
+            System.out.println(anArray[i]);
+        }
+
+        for (int element : anArray) {
+            System.out.println(element);
+        }
+    }
+
+    private static void varargs() {
+        String[] groceries = new String[] {"Milk", "Tomato", "Chips"};
+        varargMethod(groceries);
+        varargMethod("Milk", "Tomato", "Chips");
+    }
+
+    private static void varargMethod(String... varargs) {
+        for (String element : varargs) {
+            System.out.println(element);
+        }
+    }
+
+    private static void transformIntoList() {
+        Integer[] anArray = new Integer[] {1, 2, 3, 4, 5};
+
+        // Naïve implementation
+        List<Integer> aList = new ArrayList<>(); // We create an empty list
+        for (int element : anArray) {
+            // We iterate over array's elements and add them to the list
+            aList.add(element);
+        }
+
+        // Pretty implementation
+        aList = Arrays.asList(anArray);
+
+        // Drawbacks
+        try {
+            aList.remove(0);
+        } catch (UnsupportedOperationException e) {
+            System.out.println(e.getMessage());
+        }
+
+        try {
+            aList.add(6);
+        } catch (UnsupportedOperationException e) {
+            System.out.println(e.getMessage());
+        }
+
+        int[] anotherArray = new int[] {1, 2, 3, 4, 5};
+//        List<Integer> anotherList = Arrays.asList(anotherArray);
+    }
+
+    private static void transformIntoStream() {
+        int[] anArray = new int[] {1, 2, 3, 4, 5};
+        IntStream aStream = Arrays.stream(anArray);
+
+        Integer[] anotherArray = new Integer[] {1, 2, 3, 4, 5};
+        Stream<Integer> anotherStream = Arrays.stream(anotherArray, 2, 4);
+    }
+
+    private static void sort() {
+        int[] anArray = new int[] {5, 2, 1, 4, 8};
+        Arrays.sort(anArray); // anArray is now {1, 2, 4, 5, 8}
+
+        Integer[] anotherArray = new Integer[] {5, 2, 1, 4, 8};
+        Arrays.sort(anotherArray); // anArray is now {1, 2, 4, 5, 8}
+
+        String[] yetAnotherArray = new String[] {"A", "E", "Z", "B", "C"};
+        Arrays.sort(yetAnotherArray, 1, 3, Comparator.comparing(String::toString).reversed()); // yetAnotherArray is now {"A", "Z", "E", "B", "C"}
+    }
+
+    private static void search() {
+        int[] anArray = new int[] {5, 2, 1, 4, 8};
+        for (int i = 0; i < anArray.length; i++) {
+            if (anArray[i] == 4) {
+                System.out.println("Found at index " + i);
+                break;
+            }
+        }
+
+        Arrays.sort(anArray);
+        int index = Arrays.binarySearch(anArray, 4);
+        System.out.println("Found at index " + index);
+    }
+
+    private static void merge() {
+        int[] anArray = new int[] {5, 2, 1, 4, 8};
+        int[] anotherArray = new int[] {10, 4, 9, 11, 2};
+
+        int[] resultArray = new int[anArray.length + anotherArray.length];
+        for (int i = 0; i < resultArray.length; i++) {
+            resultArray[i] = (i < anArray.length ? anArray[i] : anotherArray[i - anArray.length]);
+        }
+        for (int element : resultArray) {
+            System.out.println(element);
+        }
+
+        Arrays.setAll(resultArray, i -> (i < anArray.length ? anArray[i] : anotherArray[i - anArray.length]));
+        for (int element : resultArray) {
+            System.out.println(element);
+        }
+    }
+
+}

core-java/src/main/java/com/baeldung/heapsort/Heap.java

@@ -0,0 +1,136 @@
+package com.baeldung.heapsort;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class Heap<E extends Comparable<E>> {
+
+    private List<E> elements = new ArrayList<>();
+
+    public static <E extends Comparable<E>> List<E> sort(Iterable<E> elements) {
+        Heap<E> heap = of(elements);
+
+        List<E> result = new ArrayList<>();
+
+        while (!heap.isEmpty()) {
+            result.add(heap.pop());
+        }
+
+        return result;
+    }
+
+    public static <E extends Comparable<E>> Heap<E> of(E... elements) {
+        return of(Arrays.asList(elements));
+    }
+
+    public static <E extends Comparable<E>> Heap<E> of(Iterable<E> elements) {
+        Heap<E> result = new Heap<>();
+        for (E element : elements) {
+            result.add(element);
+        }
+        return result;
+    }
+
+    public void add(E e) {
+        elements.add(e);
+        int elementIndex = elements.size() - 1;
+        while (!isRoot(elementIndex) && !isCorrectChild(elementIndex)) {
+            int parentIndex = parentIndex(elementIndex);
+            swap(elementIndex, parentIndex);
+            elementIndex = parentIndex;
+        }
+    }
+
+    public E pop() {
+        if (isEmpty()) {
+            throw new IllegalStateException("You cannot pop from an empty heap");
+        }
+
+        E result = elementAt(0);
+
+        int lasElementIndex = elements.size() - 1;
+        swap(0, lasElementIndex);
+        elements.remove(lasElementIndex);
+
+        int elementIndex = 0;
+        while (!isLeaf(elementIndex) && !isCorrectParent(elementIndex)) {
+            int smallerChildIndex = smallerChildIndex(elementIndex);
+            swap(elementIndex, smallerChildIndex);
+            elementIndex = smallerChildIndex;
+        }
+
+        return result;
+    }
+
+    public boolean isEmpty() {
+        return elements.isEmpty();
+    }
+    
+    private boolean isRoot(int index) {
+        return index == 0;
+    }
+
+    private int smallerChildIndex(int index) {
+        int leftChildIndex = leftChildIndex(index);
+        int rightChildIndex = rightChildIndex(index);
+        
+        if (!isValidIndex(rightChildIndex)) {
+            return leftChildIndex;
+        }
+
+        if (elementAt(leftChildIndex).compareTo(elementAt(rightChildIndex)) < 0) {
+            return leftChildIndex;
+        }
+
+        return rightChildIndex;
+    }
+
+    private boolean isLeaf(int index) {
+        return !isValidIndex(leftChildIndex(index));
+    }
+
+    private boolean isCorrectParent(int index) {
+        return isCorrect(index, leftChildIndex(index)) && isCorrect(index, rightChildIndex(index));
+    }
+
+    private boolean isCorrectChild(int index) {
+        return isCorrect(parentIndex(index), index);
+    }
+
+    private boolean isCorrect(int parentIndex, int childIndex) {
+        if (!isValidIndex(parentIndex) || !isValidIndex(childIndex)) {
+            return true;
+        }
+
+        return elementAt(parentIndex).compareTo(elementAt(childIndex)) < 0;
+    }
+
+    private boolean isValidIndex(int index) {
+        return index < elements.size();
+    }
+
+    private void swap(int index1, int index2) {
+        E element1 = elementAt(index1);
+        E element2 = elementAt(index2);
+        elements.set(index1, element2);
+        elements.set(index2, element1);
+    }
+
+    private E elementAt(int index) {
+        return elements.get(index);
+    }
+
+    private int parentIndex(int index) {
+        return (index - 1) / 2;
+    }
+
+    private int leftChildIndex(int index) {
+        return 2 * index + 1;
+    }
+
+    private int rightChildIndex(int index) {
+        return 2 * index + 2;
+    }
+
+}

core-java/src/test/java/com/baeldung/heapsort/HeapUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.heapsort;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.Test;
+
+public class HeapUnitTest {
+
+    @Test
+    public void givenNotEmptyHeap_whenPopCalled_thenItShouldReturnSmallestElement() {
+        // given
+        Heap<Integer> heap = Heap.of(3, 5, 1, 4, 2);
+
+        // when
+        int head = heap.pop();
+
+        // then
+        assertThat(head).isEqualTo(1);
+    }
+    
+    @Test
+    public void givenNotEmptyIterable_whenSortCalled_thenItShouldReturnElementsInSortedList() {
+        // given
+        List<Integer> elements = Arrays.asList(3, 5, 1, 4, 2);
+        
+        // when
+        List<Integer> sortedElements = Heap.sort(elements);
+        
+        // then
+        assertThat(sortedElements).isEqualTo(Arrays.asList(1, 2, 3, 4, 5));
+    }
+
+}

core-java/src/test/java/com/baeldung/modulo/ModuloUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.modulo;
+
+import org.junit.Test;
+import static org.assertj.core.api.Java6Assertions.*;
+
+public class ModuloUnitTest {
+
+  @Test
+  public void whenIntegerDivision_thenLosesRemainder(){
+    assertThat(11 / 4).isEqualTo(2);
+  }
+
+  @Test
+  public void whenDoubleDivision_thenKeepsRemainder(){
+    assertThat(11 / 4.0).isEqualTo(2.75);
+  }
+
+  @Test
+  public void whenModulo_thenReturnsRemainder(){
+    assertThat(11 % 4).isEqualTo(3);
+  }
+
+  @Test(expected = ArithmeticException.class)
+  public void whenDivisionByZero_thenArithmeticException(){
+    double result = 1 / 0;
+  }
+
+  @Test(expected = ArithmeticException.class)
+  public void whenModuloByZero_thenArithmeticException(){
+    double result = 1 % 0;
+  }
+
+  @Test
+  public void whenDivisorIsOddAndModulusIs2_thenResultIs1(){
+    assertThat(3 % 2).isEqualTo(1);
+  }
+
+  @Test
+  public void whenDivisorIsEvenAndModulusIs2_thenResultIs0(){
+    assertThat(4 % 2).isEqualTo(0);
+  }
+
+  @Test
+  public void whenItemsIsAddedToCircularQueue_thenNoArrayIndexOutOfBounds(){
+    int QUEUE_CAPACITY= 10;
+    int[] circularQueue = new int[QUEUE_CAPACITY];
+    int itemsInserted = 0;
+    for (int value = 0; value < 1000; value++) {
+      int writeIndex = ++itemsInserted % QUEUE_CAPACITY;
+      circularQueue[writeIndex] = value;
+    }
+  }
+
+}

core-kotlin/src/main/kotlin/com/baeldung/interfaces/ConflictingInterfaces.kt

@@ -0,0 +1,23 @@
+package com.baeldung.interfaces
+
+interface BaseInterface {
+    fun someMethod(): String
+}
+
+interface FirstChildInterface : BaseInterface {
+    override fun someMethod(): String {
+        return("Hello, from someMethod in FirstChildInterface")
+    }
+}
+
+interface SecondChildInterface : BaseInterface {
+    override fun someMethod(): String {
+        return("Hello, from someMethod in SecondChildInterface")
+    }
+}
+
+class ChildClass : FirstChildInterface, SecondChildInterface {
+    override fun someMethod(): String {
+        return super<SecondChildInterface>.someMethod()
+    }
+}

core-kotlin/src/main/kotlin/com/baeldung/interfaces/InterfaceDelegation.kt

@@ -0,0 +1,13 @@
+package com.baeldung.interfaces
+
+interface MyInterface {
+    fun someMethod(): String
+}
+
+class MyClass() : MyInterface {
+    override fun someMethod(): String {
+        return("Hello, World!")
+    }
+}
+
+class MyDerivedClass(myInterface: MyInterface) : MyInterface by myInterface

core-kotlin/src/main/kotlin/com/baeldung/interfaces/MultipleInterfaces.kt

@@ -0,0 +1,29 @@
+package com.baeldung.interfaces
+
+interface FirstInterface {	
+    fun someMethod(): String
+	
+    fun anotherMethod(): String {
+        return("Hello, from anotherMethod in FirstInterface")
+    }
+}
+
+interface SecondInterface {
+    fun someMethod(): String {
+        return("Hello, from someMethod in SecondInterface")
+    }
+	
+    fun anotherMethod(): String {
+        return("Hello, from anotherMethod in SecondInterface")
+    }
+}
+
+class SomeClass: FirstInterface, SecondInterface {	
+    override fun someMethod(): String {
+        return("Hello, from someMethod in SomeClass")
+    }
+	
+    override fun anotherMethod(): String {
+        return("Hello, from anotherMethod in SomeClass")
+    }
+}

core-kotlin/src/main/kotlin/com/baeldung/interfaces/SimpleInterface.kt

@@ -0,0 +1,24 @@
+package com.baeldung.interfaces
+
+interface SimpleInterface {
+    val firstProp: String
+    val secondProp: String
+        get() = "Second Property"
+    fun firstMethod(): String
+    fun secondMethod(): String {
+        println("Hello, from: " + secondProp)
+        return ""
+    }
+}
+
+class SimpleClass: SimpleInterface {
+    override val firstProp: String = "First Property"
+    override val secondProp: String
+        get() = "Second Property, Overridden!"
+    override fun firstMethod(): String {
+        return("Hello, from: " + firstProp)
+    }
+    override fun secondMethod(): String {
+        return("Hello, from: " + secondProp + firstProp)
+    }
+}

core-kotlin/src/test/kotlin/com/baeldung/interfaces/InterfaceExamplesUnitTest.kt

@@ -0,0 +1,32 @@
+package com.baeldung.interfaces
+
+import org.junit.Test
+import kotlin.test.assertEquals
+
+class InterfaceExamplesUnitTest {
+    @Test
+    fun givenAnInterface_whenImplemented_thenBehavesAsOverridden() {
+        val simpleClass = SimpleClass()
+        assertEquals("Hello, from: First Property", simpleClass.firstMethod())
+        assertEquals("Hello, from: Second Property, Overridden!First Property", simpleClass.secondMethod())
+    }
+
+    @Test
+    fun givenMultipleInterfaces_whenImplemented_thenBehavesAsOverridden() {
+        val someClass = SomeClass()
+        assertEquals("Hello, from someMethod in SomeClass", someClass.someMethod())
+        assertEquals("Hello, from anotherMethod in SomeClass", someClass.anotherMethod())
+    }
+
+    @Test
+    fun givenConflictingInterfaces_whenImplemented_thenBehavesAsOverridden() {
+        val childClass = ChildClass()
+        assertEquals("Hello, from someMethod in SecondChildInterface", childClass.someMethod())
+    }
+
+    @Test
+    fun givenAnInterface_whenImplemented_thenBehavesAsDelegated() {
+        val myClass = MyClass()
+        assertEquals("Hello, World!", MyDerivedClass(myClass).someMethod())
+    }
+}

guava-collections/.gitignore

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

guava-collections/README.md

@@ -0,0 +1,20 @@
+=========
+
+## Guava and Hamcrest Cookbooks and Examples
+
+
+### Relevant Articles: 
+- [Guava Collections Cookbook](http://www.baeldung.com/guava-collections)
+- [Guava Ordering Cookbook](http://www.baeldung.com/guava-order)
+- [Hamcrest Collections Cookbook](http://www.baeldung.com/hamcrest-collections-arrays)
+- [Partition a List in Java](http://www.baeldung.com/java-list-split)
+- [Filtering and Transforming Collections in Guava](http://www.baeldung.com/guava-filter-and-transform-a-collection)
+- [Guava – Join and Split Collections](http://www.baeldung.com/guava-joiner-and-splitter-tutorial)
+- [Guava – Lists](http://www.baeldung.com/guava-lists)
+- [Guava – Sets](http://www.baeldung.com/guava-sets)
+- [Guava – Maps](http://www.baeldung.com/guava-maps)
+- [Guide to Guava Multimap](http://www.baeldung.com/guava-multimap)
+- [Guide to Guava RangeSet](http://www.baeldung.com/guava-rangeset)
+- [Guide to Guava RangeMap](http://www.baeldung.com/guava-rangemap)
+- [Guide to Guava MinMaxPriorityQueue and EvictingQueue](http://www.baeldung.com/guava-minmax-priority-queue-and-evicting-queue)
+- [Initialize a HashMap in Java](https://www.baeldung.com/java-initialize-hashmap)

guava-collections/pom.xml

@@ -0,0 +1,66 @@
+<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>
+    <groupId>com.baeldung</groupId>
+    <artifactId>guava-collections</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>guava-collections</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <!-- utils -->
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>${commons-collections4.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+        <!-- test scoped -->
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <!-- https://mvnrepository.com/artifact/org.hamcrest/java-hamcrest -->
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>java-hamcrest</artifactId>
+            <version>${java-hamcrest.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>guava</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
+    <properties>
+        <!-- util -->
+        <guava.version>24.0-jre</guava.version>
+        <commons-lang3.version>3.5</commons-lang3.version>
+        <commons-collections4.version>4.1</commons-collections4.version>
+
+        <!-- testing -->
+        <assertj.version>3.6.1</assertj.version>
+        <java-hamcrest.version>2.0.0.0</java-hamcrest.version>
+    </properties>
+
+</project>

guava-collections/src/main/resources/logback.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>