1. Berkeley CS 61B Data Structures
http://www.cs.berkeley.edu/~jrs/61b/
2. Introduction to Computer Science using Java, Bradley Kjell, Central Connecticut State University
http://chortle.ccsu.edu/java5/index.html#03
very introductory course
3. Udeny: Java for Complete Beginners
https://www.udemy.com/java-tutorial/#/
4. Columbia University: Data Structure