This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
The warnings are caused by using non-generic versions of collection classes, rather than the generic versions that were introduced in Java 5. Like on line 49, where using ArrayList<Stock> would be the recommended approach.
Adding that compiler option gives you more specific details.