Intro to Libraries

Must know

Collections

• Java
• Guava
• vavr
• eclipse - https://www.infoq.com/articles/Refactoring-to-Eclipse-Collections/
• RichIterable in jedio (https://github.com/raisercostin/jedi-io)

VAVR

Vavr is a functional collection library. Is inspired by scala but is idiomatic to java.

• PROS
  • all collections are monadic: map, flatMap, filter
  • all collections have fluent interface
• CONS
  • heavy (a lot of supporting operations - handling redblack trees for example)
  • see https://github.com/raisercostin/software-wiki/wiki/Coding-Style#java

References

• 1st Log - The Essence of Vavr One - http://blog.vavr.io/vavr-one-log-01/

• 2nd Log - Simplifying Vavr - http://blog.vavr.io/vavr-one-log-02/

• 3rd Log - Purifying the API Surface Area - http://blog.vavr.io/purifying-the-api-surface-area/

• vavr.io - java immutable collections - Intro to Functional

  • http://www.vavr.io/vavr-docs/
  • https://www.baeldung.com/vavr

Others

Standard Java

• io (File) -
• nio (Path) - https://docs.oracle.com/javase/tutorial/essential/io
• nio2 (starting with jdk7) - https://docs.oracle.com/javase/tutorial/essential/io/fileio.html
• exceptions - https://docs.oracle.com/javase/tutorial/essential/exceptions
• concurrency - https://docs.oracle.com/javase/tutorial/essential/concurrency
• collections & streams - https://docs.oracle.com/javase/tutorial/collections/interfaces
• lambda expressions (jdk8) - https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaexpressions.html
• java OO - https://docs.oracle.com/javase/tutorial/java/javaOO
• java language - https://docs.oracle.com/javase/tutorial/java
• springframework
  • see properties - https://docs.spring.io/spring-boot/docs/current/reference/html/common-application-properties.html
  • spring boot - https://start.spring.io/
  • good resource - https://www.baeldung.com/rest-with-spring-series

Reactive Streams

There are multiple reactive-stream implementations

• CONS
  • anti-reactive - https://nurkiewicz.github.io/talks/2018/reactive-lessons
    • too hard to read
  • raisercostin experience
    • To many breaks of principle of least surprise.
      • Operations have too many gotcha, quirks, strange or un-intuitive behaviour.
        • how concat, merge differ?
        • how subscribeOn, publishOn differ?
        • when and how to execute subsequential, parallel
          • these are also influenced by schedulers/executors
      • Publishers(Flux, Mono) that aren't subscribed to do not execute and is easy to miss on this
• short intro - https://www.baeldung.com/reactor-core
• slides - https://www.slideshare.net/Pivotal/project-reactor-now-and-tomorrow
• reactor https://projectreactor.io/ - best if jdk8, supported by springframework/pivotal, support in kotlin too
• nice reference - https://projectreactor.io/docs/core/release/reference/
• nice intro - http://alexsderkach.io/comparing-java-8-rxjava-reactor/
• advanced comparison of reactive streams versions - http://akarnokd.blogspot.com/2016/03/operator-fusion-part-1.html
• https://projectreactor.io/docs/core/release/reference/
• https://www.reddit.com/r/java/comments/6acxe3/spring_reactor_vs_rxjava/
• reactive streams manifesto - http://www.reactive-streams.org/ (edited)
• performance analysis - https://kamilszymanski.github.io/resources-utilization-in-reactive-services/

Commons

• apache - https://commons.apache.org
  • commons-io
    • last: commons-io:commons-io:2.6 - Apache Commons IO 2.6 (requires JDK 1.7+)
    • https://commons.apache.org/proper/commons-io/bestpractices.html
  • commons-lang - https://commons.apache.org/proper/commons-lang/javadocs/api-release/index.html
• guava - a utilities library used by google in android too
  • last - com.google.guava:guava:26.0-jre
  • https://github.com/google/guava/wiki

Logging

• best:
  • logback-classic - uses slf4j - https://logback.qos.ch/manual/index.html
  • slf4j - generic API implemented by logback - https://www.slf4j.org/manual.html
• second best
  • log4j - deprecated by slf4j & logback - see https://www.slf4j.org/legacy.html
• not recommended
  • jul - java util logging - see https://www.slf4j.org/legacy.html
  • jcl - Jakarta Commons Logging - see https://www.slf4j.org/legacy.html

Configuration files

• https://12factor.net/config
• https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html
• use hocon - https://github.com/lightbend/config
• http://javaeeconfig.blogspot.ro/2014/08/overview-of-existing-configuration.html
• compare & samples
  • https://medium.com/@hussachai/configurations-are-you-doing-it-wrong-e4ea2672a4a9
• https://github.com/Netflix/archaius/wiki/Features

Working with time

• java3 - java7
  • use joda-time library:
• >java8 => use java.time package (JSR310)
  • http://mattgreencroft.blogspot.ro/2014/12/java-8-time-choosing-right-object.html
  • Joda Time author explains some design decisions in JSR-310 - https://blog.joda.org/2009/11/why-jsr-310-isn-joda-time_4941.html

Testing Libraries

• assertj
  • https://joel-costigliola.github.io/assertj/
• junit5
  • https://junit.org/junit5/
  • https://junit.org/junit5/docs/current/user-guide/
  • nice intro - https://www.eclipse.org/community/eclipse_newsletter/2017/october/article5.php
  • parametrized tests - https://www.petrikainulainen.net/programming/testing/junit-5-tutorial-writing-parameterized-tests/
• junit5 + hamcrest - https://www.petrikainulainen.net/programming/testing/junit-5-tutorial-writing-assertions-with-hamcrest/
• mockito - https://site.mockito.org/
• mutation testing - http://pitest.org/
• Intro to Tests
• deprecated
  • junit4 - junit5 much more features, extensibility etc

Others

• Dependency Injection: spring/guice
• mapstruct - http://mapstruct.org/
• client app: command line interpretor - CLI
  • https://argparse4j.github.io/
• suggested by guava - https://github.com/google/guava/wiki/FriendsOfGuava
• standard java - https://docs.oracle.com/javase/tutorial/
• https://github.com/a36069/theBestOfJava