i-kaplin / java8-code-kata

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Java8 Code Kata

☝ It's failing because tests are not solved yet! 😊

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

• Resolve dependencies.

$ pwd
/path/to/java8-code-kata

$ ./mvnw dependency:resolve
-> will download the dependent jar files in your .m2 directory.

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

Test sample.

@Easy @Test
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.

@Easy @Test
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 @Easy which means those tests only requires basic knowledge.

Tests annotated with @Difficult expect you to think a lot 😁

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