New unit test format

core-java-modules/core-java-8/.gitignore

@@ -0,0 +1,26 @@
+*.class
+
+0.*
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+.resourceCache
+
+# Packaged files #
+*.jar
+*.war
+*.ear
+
+# Files generated by integration tests
+*.txt
+backup-pom.xml
+/bin/
+/temp
+
+#IntelliJ specific
+.idea/
+*.iml

core-java-modules/core-java-8/README.md

@@ -0,0 +1,38 @@
+=========
+
+## Core Java 8 Cookbooks and Examples
+
+### Relevant Articles: 
+- [Guide to Java 8’s Collectors](http://www.baeldung.com/java-8-collectors)
+- [New Features in Java 8](http://www.baeldung.com/java-8-new-features)
+- [The Double Colon Operator in Java 8](http://www.baeldung.com/java-8-double-colon-operator)
+- [Guide to Java 8 groupingBy Collector](http://www.baeldung.com/java-groupingby-collector)
+- [Strategy Design Pattern in Java 8](http://www.baeldung.com/java-strategy-pattern)
+- [Guide to Java 8 Comparator.comparing()](http://www.baeldung.com/java-8-comparator-comparing)
+- [Guide To Java 8 Optional](http://www.baeldung.com/java-optional)
+- [Guide to the Java 8 forEach](http://www.baeldung.com/foreach-java)
+- [The Difference Between map() and flatMap()](http://www.baeldung.com/java-difference-map-and-flatmap)
+- [Static and Default Methods in Interfaces in Java](http://www.baeldung.com/java-static-default-methods)
+- [Efficient Word Frequency Calculator in Java](http://www.baeldung.com/java-word-frequency)
+- [Introduction to Spliterator in Java](http://www.baeldung.com/java-spliterator)
+- [Java 8 Math New Methods](http://www.baeldung.com/java-8-math)
+- [Overview of Java Built-in Annotations](http://www.baeldung.com/java-default-annotations)
+- [Finding Min/Max in an Array with Java](http://www.baeldung.com/java-array-min-max)
+- [Internationalization and Localization in Java 8](http://www.baeldung.com/java-8-localization)
+- [Java Optional – orElse() vs orElseGet()](http://www.baeldung.com/java-optional-or-else-vs-or-else-get)
+- [Method Parameter Reflection in Java](http://www.baeldung.com/java-parameter-reflection)
+- [Java 8 Unsigned Arithmetic Support](http://www.baeldung.com/java-unsigned-arithmetic)
+- [Generalized Target-Type Inference in Java](http://www.baeldung.com/java-generalized-target-type-inference)
+- [Overriding System Time for Testing in Java](http://www.baeldung.com/java-override-system-time)
+- [Set the Time Zone of a Date in Java](https://www.baeldung.com/java-set-date-time-zone)
+- [An Overview of Regular Expressions Performance in Java](https://www.baeldung.com/java-regex-performance)
+- [Java Primitives versus Objects](https://www.baeldung.com/java-primitives-vs-objects)
+- [How to Use if/else Logic in Java 8 Streams](https://www.baeldung.com/java-8-streams-if-else-logic)
+- [How to Replace Many if Statements in Java](https://www.baeldung.com/java-replace-if-statements)
+- [Java @Override Annotation](https://www.baeldung.com/java-override)
+- [Java @SuppressWarnings Annotation](https://www.baeldung.com/java-suppresswarnings)
+- [Java @SafeVarargs Annotation](https://www.baeldung.com/java-safevarargs)
+- [Java @Deprecated Annotation](https://www.baeldung.com/java-deprecated)
+- [Java 8 Predicate Chain](https://www.baeldung.com/java-predicate-chain)
+- [Creating a Custom Annotation in Java](https://www.baeldung.com/java-custom-annotation)
+- [The Difference Between Collection.stream().forEach() and Collection.forEach()](https://www.baeldung.com/java-collection-stream-foreach)

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

@@ -0,0 +1,198 @@
+<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>core-java-8</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-8</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>${commons-collections4.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>${commons-io.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>log4j</groupId>
+            <artifactId>log4j</artifactId>
+            <version>${log4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-codec</groupId>
+            <artifactId>commons-codec</artifactId>
+            <version>${commons-codec.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <!-- test scoped -->
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.jayway.awaitility</groupId>
+            <artifactId>awaitility</artifactId>
+            <version>${avaitility.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-core</artifactId>
+            <version>${jmh-core.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-generator-annprocess</artifactId>
+            <version>${jmh-generator.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-generator-bytecode</artifactId>
+            <version>${jmh-generator.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.codepoetics</groupId>
+            <artifactId>protonpack</artifactId>
+            <version>${protonpack.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.vavr</groupId>
+            <artifactId>vavr</artifactId>
+            <version>${vavr.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>joda-time</groupId>
+            <artifactId>joda-time</artifactId>
+            <version>${joda.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.aspectj</groupId>
+            <artifactId>aspectjrt</artifactId>
+            <version>${asspectj.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.aspectj</groupId>
+            <artifactId>aspectjweaver</artifactId>
+            <version>${asspectj.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.powermock</groupId>
+            <artifactId>powermock-module-junit4</artifactId>
+            <version>${powermock.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.powermock</groupId>
+            <artifactId>powermock-api-mockito2</artifactId>
+            <version>${powermock.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jmockit</groupId>
+            <artifactId>jmockit</artifactId>
+            <version>${jmockit.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>core-java-8</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                    <compilerArgument>-parameters</compilerArgument>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <version>${spring-boot-maven-plugin.version}</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>repackage</goal>
+                        </goals>
+                        <configuration>
+                            <classifier>spring-boot</classifier>
+                            <mainClass>org.baeldung.executable.ExecutableMavenJar</mainClass>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>${maven-surefire-plugin.version}</version>
+                <configuration>
+                    <argLine>
+                        -javaagent:${settings.localRepository}/org/jmockit/jmockit/${jmockit.version}/jmockit-${jmockit.version}.jar
+                    </argLine>
+                    <disableXmlReport>true</disableXmlReport>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <!-- util -->
+        <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>
+        <commons-codec.version>1.10</commons-codec.version>
+        <vavr.version>0.9.0</vavr.version>
+        <protonpack.version>1.13</protonpack.version>
+        <joda.version>2.10</joda.version>
+        <!-- testing -->
+        <assertj.version>3.6.1</assertj.version>
+        <asspectj.version>1.8.9</asspectj.version>
+        <powermock.version>2.0.0-RC.4</powermock.version>
+        <jmockit.version>1.44</jmockit.version>
+        <avaitility.version>1.7.0</avaitility.version>
+        <jmh-core.version>1.19</jmh-core.version>
+        <jmh-generator.version>1.19</jmh-generator.version>
+        <spring-boot-maven-plugin.version>2.0.4.RELEASE</spring-boot-maven-plugin.version>
+        <!-- plugins -->
+        <maven-compiler-plugin.version>3.8.0</maven-compiler-plugin.version>
+        <maven-surefire-plugin.version>2.22.1</maven-surefire-plugin.version>
+    </properties>
+</project>

core-java-modules/core-java-8/src/main/java/com/baeldung/annotations/ClassWithAnnotation.java

@@ -0,0 +1,5 @@
+package com.baeldung.annotations;
+
+@Deprecated
+class ClassWithAnnotation {
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/annotations/ClassWithDeprecatedMethod.java

@@ -0,0 +1,9 @@
+package com.baeldung.annotations;
+
+class ClassWithDeprecatedMethod {
+
+    @Deprecated
+    static void deprecatedMethod() {
+
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/annotations/ClassWithSafeVarargs.java

@@ -0,0 +1,11 @@
+package com.baeldung.annotations;
+
+class ClassWithSafeVarargs<T> {
+
+    @SafeVarargs
+    final void iterateOverVarargs(T... args) {
+        for (T x : args) {
+            // do stuff with x
+        }
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/annotations/ClassWithSuppressWarnings.java

@@ -0,0 +1,9 @@
+package com.baeldung.annotations;
+
+class ClassWithSuppressWarnings {
+
+    @SuppressWarnings("deprecation")
+    void useDeprecatedMethod() {
+        ClassWithDeprecatedMethod.deprecatedMethod(); // no warning is generated here
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/annotations/IntConsumer.java

@@ -0,0 +1,8 @@
+package com.baeldung.annotations;
+
+@FunctionalInterface
+interface IntConsumer {
+
+    void accept(Integer number);
+
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/annotations/Interval.java

@@ -0,0 +1,8 @@
+package com.baeldung.annotations;
+
+import java.lang.annotation.Repeatable;
+
+@Repeatable(Intervals.class)
+@interface Interval {
+    int hour() default 1;
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/annotations/IntervalUsage.java

@@ -0,0 +1,9 @@
+package com.baeldung.annotations;
+
+public class IntervalUsage {
+
+    @Interval(hour = 17)
+    @Interval(hour = 13)
+    void doPeriodicCleanup() {
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/annotations/Intervals.java

@@ -0,0 +1,5 @@
+package com.baeldung.annotations;
+
+@interface Intervals {
+    Interval[] value();
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/annotations/MyAnnotation.java

@@ -0,0 +1,11 @@
+package com.baeldung.annotations;
+
+import java.lang.annotation.*;
+
+@Inherited
+@Documented
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.LOCAL_VARIABLE, ElementType.FIELD})
+@interface MyAnnotation {
+
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/annotations/MyAnnotationTarget.java

@@ -0,0 +1,16 @@
+package com.baeldung.annotations;
+
+class MyAnnotationTarget {
+
+    // this is OK
+    @MyAnnotation
+    String someField;
+
+    // @MyAnnotation <- this is invalid usage!
+    void doSomething() {
+
+        // this also works
+        @MyAnnotation
+        String localVariable;
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/annotations/MyOperation.java

@@ -0,0 +1,6 @@
+package com.baeldung.annotations;
+
+interface MyOperation {
+
+    void perform();
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/annotations/MyOperationImpl.java

@@ -0,0 +1,9 @@
+package com.baeldung.annotations;
+
+class MyOperationImpl implements MyOperation {
+
+    @Override
+    public void perform() {
+
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/aspect/ChangeCallsToCurrentTimeInMillisMethod.aj

@@ -0,0 +1,9 @@
+package com.baeldung.aspect;
+
+public aspect ChangeCallsToCurrentTimeInMillisMethod {
+    long around():
+            call(public static native long java.lang.System.currentTimeMillis())
+                    && within(user.code.base.pckg.*) {
+        return 0;
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/customannotations/Init.java

@@ -0,0 +1,13 @@
+package com.baeldung.customannotations;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+@Retention(RUNTIME)
+@Target(METHOD)
+public @interface Init {
+
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/customannotations/JsonElement.java

@@ -0,0 +1,13 @@
+package com.baeldung.customannotations;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+@Retention(RUNTIME)
+@Target({ FIELD })
+public @interface JsonElement {
+    public String key() default "";
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/customannotations/JsonSerializable.java

@@ -0,0 +1,13 @@
+package com.baeldung.customannotations;
+
+import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+@Retention(RUNTIME)
+@Target(TYPE)
+public @interface JsonSerializable {
+
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/customannotations/JsonSerializationException.java

@@ -0,0 +1,10 @@
+package com.baeldung.customannotations;
+
+public class JsonSerializationException extends RuntimeException {
+
+    private static final long serialVersionUID = 1L;
+
+    public JsonSerializationException(String message) {
+        super(message);
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/customannotations/ObjectToJsonConverter.java

@@ -0,0 +1,67 @@
+package com.baeldung.customannotations;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+public class ObjectToJsonConverter {
+    public String convertToJson(Object object) throws JsonSerializationException {
+        try {
+
+            checkIfSerializable(object);
+            initializeObject(object);
+            return getJsonString(object);
+
+        } catch (Exception e) {
+            throw new JsonSerializationException(e.getMessage());
+        }
+    }
+
+    private void checkIfSerializable(Object object) {
+        if (Objects.isNull(object)) {
+            throw new JsonSerializationException("Can't serialize a null object");
+        }
+
+        Class<?> clazz = object.getClass();
+        if (!clazz.isAnnotationPresent(JsonSerializable.class)) {
+            throw new JsonSerializationException("The class " + clazz.getSimpleName() + " is not annotated with JsonSerializable");
+        }
+    }
+
+    private void initializeObject(Object object) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException {
+        Class<?> clazz = object.getClass();
+        for (Method method : clazz.getDeclaredMethods()) {
+            if (method.isAnnotationPresent(Init.class)) {
+                method.setAccessible(true);
+                method.invoke(object);
+            }
+        }
+    }
+
+    private String getJsonString(Object object) throws IllegalArgumentException, IllegalAccessException {
+        Class<?> clazz = object.getClass();
+        Map<String, String> jsonElementsMap = new HashMap<>();
+        for (Field field : clazz.getDeclaredFields()) {
+            field.setAccessible(true);
+            if (field.isAnnotationPresent(JsonElement.class)) {
+                jsonElementsMap.put(getKey(field), (String) field.get(object));
+            }
+        }
+
+        String jsonString = jsonElementsMap.entrySet()
+            .stream()
+            .map(entry -> "\"" + entry.getKey() + "\":\"" + entry.getValue() + "\"")
+            .collect(Collectors.joining(","));
+        return "{" + jsonString + "}";
+    }
+
+    private String getKey(Field field) {
+        String value = field.getAnnotation(JsonElement.class)
+            .key();
+        return value.isEmpty() ? field.getName() : value;
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/customannotations/Person.java

@@ -0,0 +1,66 @@
+package com.baeldung.customannotations;
+
+@JsonSerializable
+public class Person {
+    @JsonElement
+    private String firstName;
+    @JsonElement
+    private String lastName;
+    @JsonElement(key = "personAge")
+    private String age;
+
+    private String address;
+
+    public Person(String firstName, String lastName) {
+        super();
+        this.firstName = firstName;
+        this.lastName = lastName;
+    }
+
+    public Person(String firstName, String lastName, String age) {
+        this.firstName = firstName;
+        this.lastName = lastName;
+        this.age = age;
+    }
+
+    @Init
+    private void initNames() {
+        this.firstName = this.firstName.substring(0, 1)
+            .toUpperCase() + this.firstName.substring(1);
+        this.lastName = this.lastName.substring(0, 1)
+            .toUpperCase() + this.lastName.substring(1);
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public String getAge() {
+        return age;
+    }
+
+    public void setAge(String age) {
+        this.age = age;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/defaultstaticinterfacemethods/application/Application.java

@@ -0,0 +1,18 @@
+package com.baeldung.defaultstaticinterfacemethods.application;
+
+import com.baeldung.defaultstaticinterfacemethods.model.Car;
+import com.baeldung.defaultstaticinterfacemethods.model.Vehicle;
+
+public class Application {
+
+    public static void main(String[] args) {
+
+        Vehicle car = new Car("BMW");
+        System.out.println(car.getBrand());
+        System.out.println(car.speedUp());
+        System.out.println(car.slowDown());
+        System.out.println(car.turnAlarmOn());
+        System.out.println(car.turnAlarmOff());
+        System.out.println(Vehicle.getHorsePower(2500, 480));
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/defaultstaticinterfacemethods/model/Alarm.java

@@ -0,0 +1,12 @@
+package com.baeldung.defaultstaticinterfacemethods.model;
+
+public interface Alarm {
+
+    default String turnAlarmOn() {
+        return "Turning the alarm on.";
+    }
+
+    default String turnAlarmOff() {
+        return "Turning the alarm off.";
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/defaultstaticinterfacemethods/model/Car.java

@@ -0,0 +1,25 @@
+package com.baeldung.defaultstaticinterfacemethods.model;
+
+public class Car implements Vehicle {
+
+    private final String brand;
+
+    public Car(String brand) {
+        this.brand = brand;
+    }
+
+    @Override
+    public String getBrand() {
+        return brand;
+    }
+
+    @Override
+    public String speedUp() {
+        return "The car is speeding up.";
+    }
+
+    @Override
+    public String slowDown() {
+        return "The car is slowing down.";
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/defaultstaticinterfacemethods/model/Motorbike.java

@@ -0,0 +1,25 @@
+package com.baeldung.defaultstaticinterfacemethods.model;
+
+public class Motorbike implements Vehicle {
+
+    private final String brand;
+
+    public Motorbike(String brand) {
+        this.brand = brand;
+    }
+
+    @Override
+    public String getBrand() {
+        return brand;
+    }
+
+    @Override
+    public String speedUp() {
+        return "The motorbike is speeding up.";
+    }
+
+    @Override
+    public String slowDown() {
+        return "The motorbike is slowing down.";
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/defaultstaticinterfacemethods/model/MultiAlarmCar.java

@@ -0,0 +1,35 @@
+package com.baeldung.defaultstaticinterfacemethods.model;
+
+public class MultiAlarmCar implements Vehicle, Alarm {
+
+    private final String brand;
+
+    public MultiAlarmCar(String brand) {
+        this.brand = brand;
+    }
+
+    @Override
+    public String getBrand() {
+        return brand;
+    }
+
+    @Override
+    public String speedUp() {
+        return "The motorbike is speeding up.";
+    }
+
+    @Override
+    public String slowDown() {
+        return "The mootorbike is slowing down.";
+    }
+
+    @Override
+    public String turnAlarmOn() {
+        return Vehicle.super.turnAlarmOn() + " " + Alarm.super.turnAlarmOn();
+    }
+
+    @Override
+    public String turnAlarmOff() {
+        return Vehicle.super.turnAlarmOff() + " " + Alarm.super.turnAlarmOff();
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/defaultstaticinterfacemethods/model/Vehicle.java

@@ -0,0 +1,22 @@
+package com.baeldung.defaultstaticinterfacemethods.model;
+
+public interface Vehicle {
+
+    String getBrand();
+
+    String speedUp();
+
+    String slowDown();
+
+    default String turnAlarmOn() {
+        return "Turning the vehice alarm on.";
+    }
+
+    default String turnAlarmOff() {
+        return "Turning the vehicle alarm off.";
+    }
+
+    static int getHorsePower(int rpm, int torque) {
+        return (rpm * torque) / 5252;
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/doublecolon/Computer.java

@@ -0,0 +1,85 @@
+package com.baeldung.doublecolon;
+
+public class Computer {
+
+    private Integer age;
+    private String color;
+    private Integer healty;
+
+    Computer(final int age, final String color) {
+        this.age = age;
+        this.color = color;
+    }
+
+    Computer(final Integer age, final String color, final Integer healty) {
+        this.age = age;
+        this.color = color;
+        this.healty = healty;
+    }
+
+    public Computer() {
+    }
+
+    public Integer getAge() {
+        return age;
+    }
+
+    public void setAge(final Integer age) {
+        this.age = age;
+    }
+
+    String getColor() {
+        return color;
+    }
+
+    public void setColor(final String color) {
+        this.color = color;
+    }
+
+    Integer getHealty() {
+        return healty;
+    }
+
+    void setHealty(final Integer healty) {
+        this.healty = healty;
+    }
+
+    public void turnOnPc() {
+        System.out.println("Computer turned on");
+    }
+
+    public void turnOffPc() {
+        System.out.println("Computer turned off");
+    }
+
+    public Double calculateValue(Double initialValue) {
+        return initialValue / 1.50;
+    }
+
+    @Override
+    public String toString() {
+        return "Computer{" + "age=" + age + ", color='" + color + '\'' + ", healty=" + healty + '}';
+    }
+
+    @Override
+    public boolean equals(final Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+
+        final Computer computer = (Computer) o;
+
+        return (age != null ? age.equals(computer.age) : computer.age == null) && (color != null ? color.equals(computer.color) : computer.color == null);
+
+    }
+
+    @Override
+    public int hashCode() {
+        int result = age != null ? age.hashCode() : 0;
+        result = 31 * result + (color != null ? color.hashCode() : 0);
+        return result;
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/doublecolon/ComputerUtils.java

@@ -0,0 +1,27 @@
+package com.baeldung.doublecolon;
+
+import com.baeldung.doublecolon.function.ComputerPredicate;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ComputerUtils {
+
+    static final ComputerPredicate after2010Predicate = (c) -> (c.getAge() > 2010);
+    static final ComputerPredicate blackPredicate = (c) -> "black".equals(c.getColor());
+
+    public static List<Computer> filter(final List<Computer> inventory, final ComputerPredicate p) {
+
+        final List<Computer> result = new ArrayList<>();
+        inventory.stream().filter(p::filter).forEach(result::add);
+
+        return result;
+    }
+
+    static void repair(final Computer computer) {
+        if (computer.getHealty() < 50) {
+            computer.setHealty(100);
+        }
+    }
+
+}