Java Servlet API provides several classes for handling input and output streams in servlets. Here are some commonly used servlet input and output stream classes:

1. ServletInputStream - This class represents the input stream for reading data from a client request. You can obtain an instance of this class from the HttpServletRequest object by calling the getInputStream() method. You can then read data from the input stream using methods such as read(), readLine(), or read(byte[]).

2. ServletOutputStream - This class represents the output stream for writing data to a client response. You can obtain an instance of this class from the HttpServletResponse object by calling the getOutputStream() method. You can then write data to the output stream using methods such as write(int), write(byte[]), or print(String).

3. PrintWriter - This class provides a convenient way to write character-based data to a client response. You can obtain an instance of this class from the HttpServletResponse object by calling the getWriter() method. You can then write data to the output stream using methods such as print(String) or println(String).

4. ByteArrayInputStream - This class provides a way to read data from a byte array. You can create an instance of this class by passing a byte array to its constructor. You can then use it to read data from the byte array using methods such as read() or read(byte[]).

5. ByteArrayOutputStream - This class provides a way to write data to a byte array. You can create an instance of this class and write data to it using methods such as write(int) or write(byte[]). You can then obtain the resulting byte array by calling its toByteArray() method.

These input and output stream classes can be used to read and write data in various formats, such as text, binary, or serialized data. They provide a flexible and efficient way to handle data in servlets.