The FileOutputStream class in Java provides several methods for writing data to a file as a stream of bytes. Some of the commonly used methods of the FileOutputStream class are:

1. write(int b) - Writes a single byte of data to the output stream.

2. write(byte[] b) - Writes a sequence of bytes to the output stream.

3. write(byte[] b, int off, int len) - Writes len bytes of data from the byte array b to the output stream, starting at the specified offset off.

4. flush() - Flushes any buffered output bytes to the underlying file.

5. close() - Closes the output stream, releasing any system resources associated with the stream.

It's important to note that the behavior of these methods can vary depending on the specific implementation of the FileOutputStream class. For example, the FileOutputStream class may buffer data internally to improve performance, and the behavior of the write method may be affected by this buffering.

Additionally, it's important to remember to close the output stream using the close() method when you're finished writing data to the file. Failing to do so can result in data corruption or loss, and may cause issues when trying to read the file later.

Overall, the FileOutputStream class provides a flexible and efficient way of writing data to a file in Java, and the various methods it provides can be used to write data in a variety of different ways depending on your specific needs. By using the various methods of the FileOutputStream class, you can write data to files in a variety of formats, including text files, binary files, and more.