Rollerball questions

• Java meaning of .java~
• About the HashMap, rehashing
• Optional method in Collection interface [duplicate]
• Inheritance instance variables with Java
• Where can I find the list of attributes name?
• How can I get a RejectedExecutionException
• What does "\1" represent in this Java string?
• How does "%tB" formatter work?
• Why only char[] gets printed out as if with the toString method?
• Difference between doGet and doHead methods

Rollerball answers