The OutputStream class is an abstract class in Java that provides a standard way of writing data to different destinations in the form of bytes. It defines several methods that are commonly used for writing data, including:

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

2. write(byte[] b) - Writes the entire byte array b to the output stream.

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

4. flush() - Flushes the output stream, forcing any buffered output to be written to its destination.

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 subclass of OutputStream that you are using. For example, the FileOutputStream class provides additional methods for working with files, while the ByteArrayOutputStream class is designed specifically for writing data to a byte array.

Overall, the OutputStream class provides a flexible and efficient way of writing data to different destinations 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 subclasses of OutputStream, you can write data to files, network connections, and other output destinations in the form of bytes.