The OutputStreamWriter is a class in Java that bridges character streams and byte streams. It allows you to write characters to an output stream, converting them into bytes using a specified character encoding. This is useful when you need to write text data to files or network connections that require byte-level output. By using OutputStreamWriter, developers can easily handle different character encodings, such as UTF-8 or ISO-8859-1. It is typically used in conjunction with other classes like FileOutputStream or BufferedOutputStream to enhance performance and manage resources efficiently while writing text data.