Java8 Code Kata

What is Code Kata?

According to www.codekatas.org

Code Kata is a term coined by Dave Thomas, co-author of the book The Pragmatic Programmer, in a bow to the Japanese concept of kata in the martial arts. A code kata is an exercise in programming which helps a programmer hone their skills through practice and repetition.

Also refer codekata.com

What is Java8 Code Kata?

The Java8 Code Kata is created to walk-through java8 new API functions. I hope this helps you learn Java8 and get used to it. Repeating exercises will definitely upgrade your skills.

Usage

Edit the unit tests to pass them by following its description.

Test sample.

@Test
@Necessity(true)
public void simpleAddition() {
    /**
     * Get an addition result of 1 and 2 by using an operator "+".
     */
    Integer added = null;

    assertThat(added, is(3));
}

You need to edit the program under the comment.

Solution sample.

@Test
@Necessity(true)
public void simpleAddition() {
    /**
     * Get an addition result of 1 and 2 by using an operator "+".
     */
    Integer added = 1 + 2;

    assertThat(added, is(3));
}

Most tests are annotated with @Necessity(true) which means the test only requires basic knowledge.

Tests annotated with @Necessity(false) are more difficult and need to think to solve them.

Where are the answers?

Check the 'solution' branch, but please try to solve by yourself at first.

Modules

collection-interfaces

• Exercise1Test.java

Iterable#forEach, Collection#removeIf, List#replaceAll, List#sort, Collection#stream and Collection#parallelStream

• Exercise2Test.java

Map#getOrDefault, Map#putIfAbsent, Map#merge and Map#computeIfPresent

stream-api

• Exercise1Test.java

Stream#filter and Stream#map

• Exercise2Test.java

Stream#sorted, Stream#distinct, Stream#limit and Stream#flatMap

• Exercise3Test.java

Stream#count, Stream#max and Stream#min

• Exercise4Test.java

Stream#findFirst, Stream#allMatch, Stream#anyMatch and Stream#noneMatch

• Exercise5Test.java

Stream#collect and Collectors

• Exercise6Test.java

Stream#of and Stream#iterate

• Exercise7Test.java

IntStream, LongStream and DoubleStream

• Exercise8Test.java

Advanced problems

• Exercise9Test.java

Collector

date-and-time-api

• Exercise1Test.java

LocalDate#of, LocalDate#parse, LocalDate#with, LocalDate#plus, LocalDate#minus, LocalDate#isAfter, LocalDate#isBefore and LocalDate#until

• Exercise2Test.java

LocalTime#of, LocalTime#parse, LocalTime#with, LocalTime#plus, LocalTime#minus, LocalTime#isAfter, LocalTime#isBefore and LocalTime#truncatedTo

• Exercise3Test.java

LocalDateTime#of, LocalDateTime#parse, LocalDateTime#format, LocalDateTime#toLocalDate, LocalDateTime#toLocalTime, LocalDate#atTime and LocalTime#atDate

• Exercise4Test.java

ZonedDateTime#of, ZonedDateTime#parse, ZonedDateTime#format, LocalDateTime#atZone, ZonedDateTime#withZoneSameInstant and ZonedDateTime#withZoneSameLocal

• Exercise5Test.java

LocalDateTime to java.sql.Timestamp, LocalDate to java.sql.Date, and vice versa