Although a sequential access mechanism traverses file record in a linear fashion, random access in a file enables us to access individual records directly without searching through other records.
Flat files in general are not meant to be accessed in this manner; moreover, Java does not impose any structure on a file.
Each record is written and read from the file with the help of the methods .
Here, in this article, we shall see one such way where a flat file access mechanism can be customized like a database CRUD operation.Once you have a file object that is correctly opened (i.e., for update, and as a binary rather than a text file), you can perform as many updates on the file as you want before closing the file again.These calls are shown here to emphasize the proper technique for opening a file for random-access updates and the importance of closing a file when you are done with it.(A CRUD operation can also be implemented in a sequential access file as well, but in this case we have to rewrite the complete file content on each CRUD operation to achieve the same effect.This is infeasible, especially when we can formulate a direct access mechanism through code in Java.) Let the following POJO be our simple record structure: impose a restriction of a fixed length character sequence whi nreading or writing string values from the file, respectively.