java

http://www.youtube.com/course?list=ECFE2CE09D83EE3E28

https://www.udemy.com/java-tutorial/#/

http://www.learnjavaonline.org/en/Hello%2C_World%21

http://www.guru99.com/java-tutorial.html

Java notes:

http://ktbase.blogspot.com/2014/04/java-notes_20.html
http://ktbase.blogspot.com/2014/04/java-basics.html
poi guide:

http://poi.apache.org/spreadsheet/quick-guide.html