java collection

http://java.sun.com/developer/onlineTraining/collections/Collection.html

java 6

http://jcp.org/aboutJava/communityprocess/final/jsr270/index.html

array vs arraylist

http://www.javafaq.nu/java-article1111.html

java garbage collection

http://www.javaworld.com/javaworld/jw-08-1996/jw-08-gc.html?page=1