[JAVA] IO

/**
 * This abstract class is the superclass of all classes representing
 * an input stream of bytes.
 *
 * Applications that need to define a subclass of <code>InputStream</code>
 * must always provide a method that returns the next byte of input.
 */
public abstract class InputStream implements Closeable {
    ...
}

/**
 * This abstract class is the superclass of all classes representing
 * an output stream of bytes. An output stream accepts output bytes
 * and sends them to some sink.
 * 
 * Applications that need to define a subclass of
 * <code>OutputStream</code> must always provide at least a method
 * that writes one byte of output.
 */
public abstract class OutputStream implements Closeable, Flushable {
    ...
}