Research ? What research do you want to do on this ?
Always try and study the stack trace. It contains the name of the exception that occurred, a short description and the line of code on which the exception occurred. The line number and the class mentioned on the top of your stack might not be visible if it is a part of some api. If that is the case go down the stack until you find the line of code you have written. Your stack says that it is a StringIndexOutOfBoundsException. And from the information in the last bit of stack trace, you are trying to substring from a string using indices which are not valid i.e out of bound.
Always try to google the error you get. You will get a solution much more faster than posting a question. And if you do, provide more details on what issue are you facing, what your confusion is and what help are you looking to get.