In your first question you ask 'How do I inherit the warehouse while extending JFrame?"
The answer is, you probably don't want to extend JFrame, and may not to want inherit from warehouse, either. Instead, you probably want another class that HAS-A warehouse, and HAS-A JFrame (composition) rather than IS-A warehouse and IS-A JFrame (inheritance). This third class in your application would feed the information the JFrame needs by getting it from the warehouse.
See
This JavaWorld article for an introduction to the difference between inheritance and composition, but do a more extensive search to get a better understanding.
The second question is "How to transfer data from one JFrame to another?" This will be easier when you implement the Composition approach, and will be a matter of:
1) Providing an ActionListener that gets called when the button on Frame1 is pushed
2) Getting the proper information from the warehouse
3) Sending the information to JFrame2 via whatever method calls you make available.