There are several reasons why the FileWriter class might not be working as expected in Java.
Here are some common issues to check:
File not found: If you are trying to write to a file that doesn't exist, the FileWriter constructor will throw a FileNotFoundException. Make sure that the file you are trying to write to exists, or use the FileWriter constructor that takes a boolean argument to specify whether to create the file if it doesn't exist.
Permission denied: If you don't have permission to write to the file, the FileWriter constructor will throw a SecurityException. Make sure that you have the necessary permissions to write to the file.
File is a directory: If you are trying to write to a file that is actually a directory, the FileWriter constructor will throw a FileNotFoundException. Make sure that you are specifying a file and not a directory.
Out of disk space: If there is not enough disk space available to write to the file, the write() method will throw an IOException. Make sure that you have enough free disk space.
File is read-only: If the file is marked as read-only, the write() method will throw an IOException. Make sure that the file is not read-only, or use the FileWriter constructor that takes a boolean argument to specify whether to append to the file or overwrite it.
If you are experiencing a different issue with the FileWriter class, it's a good idea to check the documentation and look for any error messages that might provide more information about the problem.