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Oracle Java8 MOOC Lesson Solutions
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‎oracle-mooc-java8/homeworks/Lesson01.pdf

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‎oracle-mooc-java8/homeworks/Lesson02.pdf

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‎oracle-mooc-java8/homeworks/Lesson03.pdf

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‎oracle-mooc-java8/java8-mooc-homeworks/pom.xml renamed to ‎oracle-mooc-java8/homeworks/solutions/pom.xml

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<packaging>jar</packaging>
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<properties>
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<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
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<maven.compiler.source>1.7</maven.compiler.source>
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<maven.compiler.target>1.7</maven.compiler.target>
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<maven.compiler.source>1.8</maven.compiler.source>
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<maven.compiler.target>1.8</maven.compiler.target>
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</properties>
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<name>solutions</name>
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</project>

‎oracle-mooc-java8/homeworks/solutions/src/main/java/org/ecabrerar/examples/java8/mooc/lesson1/SolutionsLesson1.java

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package org.ecabrerar.examples.java8.mooc.lesson1;
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/**
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* Copyright © 2014, Oracle and/or its affiliates. All rights reserved.
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*
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* JDK 8 MOOC Lesson 1 homework
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*/
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//package lesson1;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.List;
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import java.util.Map;
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import java.util.TreeMap;
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/**
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* @author Speakjava ([email protected])
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*/
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public class SolutionsLesson1 {
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/**
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* Run the exercises to ensure we got the right answers
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*/
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public void runExercises() {
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System.out.println("JDK 8 Lambdas and Streams MOOC Lesson 1");
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System.out.println("Running exercise 1 solution...");
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exercise1();
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System.out.println("Running exercise 2 solution...");
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exercise2();
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System.out.println("Running exercise 3 solution...");
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exercise3();
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System.out.println("Running exercise 4 solution...");
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exercise4();
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System.out.println("Running exercise 5 solution...");
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exercise5();
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}
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/**
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* All exercises should be completed using Lambda expressions and the new
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* methods added to JDK 8 where appropriate. There is no need to use an
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* explicit loop in any of the code. Use method references rather than full
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* lambda expressions wherever possible.
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*/
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/**
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* Exercise 1
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*
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* Create a string that consists of the first letter of each word in the
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* list of Strings provided.
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*/
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private void exercise1() {
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List<String> list = Arrays.asList(
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"alpha", "bravo", "charlie", "delta", "echo", "foxtrot");
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/* YOUR CODE HERE */
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final StringBuilder sb = new StringBuilder();
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// list.forEach((String t) -> {
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// sb.append(t.charAt(0));
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// });
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list.forEach(s -> sb.append(s.charAt(0)));
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String result = sb.toString();
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System.out.println("Exercise 1 result = " + result);
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}
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/**
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* Exercise 2
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*
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* Remove the words that have odd lengths from the list.
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*/
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private void exercise2() {
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List<String> list = new ArrayList<>(Arrays.asList(
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"alpha", "bravo", "charlie", "delta", "echo", "foxtrot"));
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/* YOUR CODE HERE */
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// list.removeIf((String t) -> t.length()% 2 > 0);
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list.removeIf(s -> s.length()% 2 > 0);
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list.forEach(System.out::println);
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}
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/**
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* Exercise 3
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*
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* Replace every word in the list with its upper case equivalent.
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*/
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private void exercise3() {
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List<String> list = new ArrayList<>(Arrays.asList(
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"alpha", "bravo", "charlie", "delta", "echo", "foxtrot"));
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/* YOUR CODE HERE */
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list.replaceAll(String::toUpperCase);
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list.stream().forEach(System.out::println);
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}
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/**
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* Exercise 4
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*
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* Convert every key-value pair of the map into a string and append them all
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* into a single string, in iteration order.
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*/
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private void exercise4() {
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Map<String, Integer> map = new TreeMap<>();
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map.put("c", 3);
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map.put("b", 2);
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map.put("a", 1);
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/* YOUR CODE HERE */
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final StringBuilder sb = new StringBuilder();
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// map.forEach((String k, Integer v) -> {
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// sb.append(k);
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// });
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map.forEach((k,v) -> sb.append(String.format("%s%s", k,v)));
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//System.out.println(result.toString());
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String result = sb.toString();
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System.out.println("Exercise 4 result = " + result);
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}
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/**
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* Exercise 5
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*
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* Create a new thread that prints the numbers from the list.
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*/
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private void exercise5() {
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List<Integer> list = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
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/* YOUR CODE HERE */
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new Thread(()-> list.forEach(System.out::println)).start();
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}
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/**
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* Main entry point for application
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*
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* @param args the command line arguments
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*/
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public static void main(String[] args) {
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SolutionsLesson1 lesson = new SolutionsLesson1();
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lesson.runExercises();
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}
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}

‎oracle-mooc-java8/homeworks/solutions/src/main/java/org/ecabrerar/examples/java8/mooc/lesson2/SolutionsLesson2.java

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package org.ecabrerar.examples.java8.mooc.lesson2;
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/**
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* Copyright © 2014, Oracle and/or its affiliates. All rights reserved.
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*
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* JDK 8 MOOC Lesson 2 homework
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*/
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//package lesson2;
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import java.io.BufferedReader;
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import java.io.IOException;
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import java.nio.charset.StandardCharsets;
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import java.nio.file.Files;
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import java.nio.file.Paths;
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import java.util.Arrays;
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import java.util.List;
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import java.util.stream.Collectors;
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import java.util.stream.Stream;
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/**
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* @author Speakjava ([email protected])
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*/
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public class SolutionsLesson2 {
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private static final String WORD_REGEXP = "[- .:,]+";
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/**
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* Run the exercises to ensure we got the right answers
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*
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* @throws java.io.IOException
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*/
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public void runExercises() throws IOException {
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System.out.println("JDK 8 Lambdas and Streams MOOC Lesson 2");
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System.out.println("Running exercise 1 solution...");
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exercise1();
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System.out.println("Running exercise 2 solution...");
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exercise2();
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System.out.println("Running exercise 3 solution...");
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exercise3();
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System.out.println("Running exercise 4 solution...");
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exercise4();
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System.out.println("Running exercise 5 solution...");
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exercise5();
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System.out.println("Running exercise 6 solution...");
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exercise6();
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System.out.println("Running exercise 7 solution...");
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exercise7();
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}
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/**
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* Exercise 1
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*
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* Create a new list with all the strings from original list converted to
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* lower case and print them out.
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*/
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private void exercise1() {
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List<String> list = Arrays.asList(
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"The", "Quick", "BROWN", "Fox", "Jumped", "Over", "The", "LAZY", "DOG");
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/* YOUR CODE HERE */
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List<String> newList = list
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.stream()
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.map(String::toLowerCase)
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.collect(Collectors.toList());
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newList.forEach(System.out::println);
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}
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/**
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* Exercise 2
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*
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* Modify exercise 1 so that the new list only contains strings that have an
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* odd length
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*/
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private void exercise2() {
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List<String> list = Arrays.asList(
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"The", "Quick", "BROWN", "Fox", "Jumped", "Over", "The", "LAZY", "DOG");
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List<String> newList = list
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.stream()
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.filter(s -> (s.length() % 2)==1)
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.map(String::toLowerCase)
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.collect(Collectors.toList());
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newList.forEach(System.out::println);
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/* YOUR CODE HERE */
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}
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/**
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* Exercise 3
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*
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* Join the second, third and forth strings of the list into a single string,
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* where each word is separated by a hyphen (-). Print the resulting string.
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*/
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private void exercise3() {
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List<String> list = Arrays.asList(
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"The", "quick", "brown", "fox", "jumped", "over", "the", "lazy", "dog");
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/* YOUR CODE HERE */
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String result = list
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.stream()
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.skip(1)
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.limit(3)
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.collect(Collectors.joining("-"));
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System.out.println(result);
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}
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/**
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* Count the number of lines in the file using the BufferedReader provided
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*/
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private void exercise4() throws IOException {
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try (BufferedReader reader = Files.newBufferedReader(
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Paths.get("SonnetI.txt"), StandardCharsets.UTF_8)) {
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/* YOUR CODE HERE */
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long totalLines = reader.lines().count();
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System.out.println("Number of lines = " + totalLines);
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}
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}
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/**
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* Using the BufferedReader to access the file, create a list of words with
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* no duplicates contained in the file. Print the words.
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*
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* HINT: A regular expression, WORD_REGEXP, is already defined for your use.
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*/
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private void exercise5() throws IOException {
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try (BufferedReader reader = Files.newBufferedReader(
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Paths.get("SonnetI.txt"), StandardCharsets.UTF_8)) {
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/* YOUR CODE HERE */
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List<String> uniqueWords = reader
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.lines()
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.flatMap(line -> Stream.of(line.split(WORD_REGEXP)))
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.distinct()
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.collect(Collectors.toList());
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uniqueWords.stream().forEach(System.out::println);
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}
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}
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/**
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* Using the BufferedReader to access the file create a list of words from
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* the file, converted to lower-case and with duplicates removed, which is
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* sorted by natural order. Print the contents of the list.
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*/
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private void exercise6() throws IOException {
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try (BufferedReader reader = Files.newBufferedReader(
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Paths.get("SonnetI.txt"), StandardCharsets.UTF_8)) {
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/* YOUR CODE HERE */
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List<String> words = reader.lines()
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.flatMap(line -> Stream.of(line.split(WORD_REGEXP)))
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.map(String::toLowerCase)
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.sorted()
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.distinct()
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.collect(Collectors.toList());
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words.stream().forEach(System.out::println);
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}
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}
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/**
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* Modify exercise6 so that the words are sorted by length
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*/
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private void exercise7() throws IOException {
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try (BufferedReader reader = Files.newBufferedReader(
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Paths.get("SonnetI.txt"), StandardCharsets.UTF_8)) {
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/* YOUR CODE HERE */
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List<String> words = reader.lines()
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.flatMap(line -> Stream.of(line.split(WORD_REGEXP)))
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.map(String::toLowerCase)
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.sorted()
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.distinct()
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.collect(Collectors.toList());
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words.stream().forEach(System.out::println);
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}
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}
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/**
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* Main entry point for application
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*
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* @param args the command line arguments
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* @throws IOException If file access does not work
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*/
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public static void main(String[] args) throws IOException {
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SolutionsLesson2 lesson = new SolutionsLesson2();
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lesson.runExercises();
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}
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}
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