OpenSource projects on Java

java8-the-missing-tutorial

https://github.com/shekhargulati/java8-the-missing-tutorial

java8-tutorial

https://github.com/winterbe/java8-tutorial

Awesome Java

https://github.com/akullpp/awesome-java

Useful Java links

https://github.com/Vedenin/useful-java-links

Java

https://github.com/java-course-ee
https://github.com/javadev-org/shopizer
https://github.com/alkacon/opencms-core
https://github.com/javadev-org/javaee7-samples
https://github.com/jirkapinkas/example-eshop-vaadin
https://github.com/jirkapinkas/jsfeshop

Spring Framework

https://bitbucket.org/marley-spring/building-an-e-commerce-store-using-java-spring-framework

https://github.com/spring-projects/spring-petclinic

[Book] Alex Bretet - Spring MVC Cookbook - 2016

Application:
http://cloudstreetmarket.com/

Source codes:
https://github.com/alex-bretet/cloudstreetmarket.com

https://bitbucket.org/marley-spring/example-eshop-spring/src/master/
https://bitbucket.org/marley-spring/eshop-spring-2/src/master/
https://bitbucket.org/marley-spring/pro-spring-mvc-book-code-examples/src/master/
https://bitbucket.org/marley-spring/angularjs-springmvc-sample/src/master/

https://bitbucket.org/marley-spring/topjava02/src/master/

Oracle ADF

code examples

Some Guys

https://github.com/armdev

Interview
http://www.programmerinterview.com/index.php/java-questions/java-diamond-problem/