Category Archives: Java

Java – Covariance, Contravariance and Invariance

https://stackoverflow.com/questions/8481301/covariance-invariance-and-contravariance-explained-in-plain-english Advertisements

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Java – Guava API to sort items in collection with Ordering compound example

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Java – Spring boot with JAX-RS

Enabling Spring boot to use JAX-RS https://dzone.com/articles/using-jax-rs-with-spring-boot-instead-of-mvc http://blog.codeleak.pl/2015/01/getting-started-with-jersey-and-spring.html

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Java 9 – useful commands to inspect Module

List modules Diagnostic module dependencies

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Java 8 – general practice using Optional

0. Never, ever use null for an Optional variable. 1. Optional should be only used as a return value. : never use it for a field in Class and a method parameter. never use it in collections 2. Never try … Continue reading

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Java – Task polling example with Java 8

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Java – Java application monitoring tools

jcmd: Prints basic class, thread, and VM information for a Java process Example) jconsole: Provides a graphical view of JVM activities, including thread usage, class usage, and GC activities jhat: Reads and helps analyze memory heap dumps. This is a … Continue reading

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