InputStream (abstract)
    ByteArrayInputStream(byte[])
    FileInputStream(File)(String)(FileDescriptor)
    FilterInputStream(InputStream)
        BufferedInputStream(InputStream)
        DataInputStream(implements DataInput)(InputStream)
        PushbackInputStream(InputStream)
    ObjectInputStream(InputStream)
    PipedInputStream(PipedOutputStream)()
    SequenceInputStream(InputStream, InputStream)(Enumeration)

OutputStream (abstract)
    ByteArrayOutputStream()
    FileOutputStream(File)(String)(FileDescriptor)
    FilterOutputStream(OutputStream)
        BufferedOutputStream(OutputStream)
        DataOutputStream(OutputStream)
        PrintStream(OutputStream)
    ObjectOutputStream(OutputStream)
    PipedOutputStream(PipedInputStream)()

Reader (abstract)
    BufferedReader(Reader)
        LineNumberReader(Reader)
    CharArrayReader(char[])
    FilterReader(abstract)(Reader)
        PushbackReader(Reader)
    InputStreamReader(InputStream)
        FileReader(File)(String)(FileDescriptor)(convenience)
    PipedReader(PipedWriter)()
    StringReader(String)

Writer (abstract)
    BufferedWriter(Writer)
    CharArrayWriter()
    FilterWriter(abstract)(Writer)
    OutputStreamWriter(OutputStream)
        FileWriter(File)(String)(FileDescriptor)(convenience)
    PipedWriter(PipedReader)()
    PrintWriter(OutputStream)(Writer)
    StringWriter()

System.in is a BufferedInputStream
System.out is a PrintStream