In my Java program, they are asking me to complete this method in my book class:

Save - this method has no parameter. It should write the book catalog back to the file if the data has been changed (the same file is used for both reading and writing). Then in my main class, they ask : For the "Save data" menu, if any change has been made to the catalog, the program will save the updated catalog to the file. So, the method works perfectly when I am trying to run it one time, but when I try to run it a second time, then it just shows an error. So when I try to see the output once all the changes have been made, it shows this:

?A View From the BridgeArthur MillerDramatists Play??Data Abstraction & Problem Solving with JavaJ. Prichard and F. CarranoAddison Wesley??Database System ConceptsAbraham Silberschat. When it is suppose to show a similar for to this:

0132122306 Data Abstraction & Problem Solving with Java J. Prichard and F. Carrano Addison Wesley 2011

1400030032 My Life Bill Clinton Vintage 2005