Java Links

There are the some of the links, where they have explained some concepts in depth.

Abstraction
http://javarevisited.blogspot.de/2010/10/abstraction-in-java.html

Thread Local
http://veerasundar.com/blog/2010/11/java-thread-local-how-to-use-and-code-sample/

Class loaders
http://www.javalobby.org/java/forums/t18345.html
Class loaders
http://www.techjava.de/topics/2008/01/java-class-loading/

ClassNotFoundException
http://stackoverflow.com/questions/1457863/what-is-the-difference-between-noclassdeffounderror-and-classnotfoundexception

Heap and Stack
http://www.javatutorialhub.com/java-stack-heap.html

Memory models
http://javapapers.com/core-java/java-jvm-memory-types/

Design patterns:
http://www.oodesign.com/

Reverse single linked list:
http://www.teamten.com/lawrence/writings/reverse_a_linked_list.html
http://geek-o-pedia.blogspot.de/2007/07/how-would-you-reverse-singly-linked.html

Design principles:
http://www.vogella.com/articles/DesignPatterns/article.html#120_ooprincipless1s2f