In Java, working with files involves reading from and writing to files using the appropriate classes and methods provided in the Java IO library.

The process of reading from files involves creating a file object, opening the file for reading, and using a bufferedReader object to read each line of the file in sequence until the end of file is reached. Methods such as readLine() and close() are used to facilitate the process.

To write data to a file, a similar process is followed. A file object is created, and a bufferedWriter is used to write data to the file. Methods such as write() and close() are used to complete the process.

In both cases, error handling is an important consideration to ensure that the file is read or written correctly and that the program does not crash. Exceptions such as FileNotFoundExceptions, IOExceptions, or SecurityExceptions must be handled using try-catch blocks to avoid unexpected program crashes.

Overall, working with files in Java involves careful planning, identification, and implementation of the appropriate classes and methods. Mastery of this skill is crucial for a Java programmer to process and manipulate data from the file systems easily.