把一个对象写到一个流中相对比较简单，具体是通过调用ObjectOutputStream类的writeObject()方法实现的，那么该方法的定义为( )。
A．public final int writeObject(Object obj) throws IOException
B．public final void writeObject(Object obj) throws IOExcepfion
C．public Object writeObject(Object obj) throws IOExcepfion
D．public final Object writeObject(Object obj) throws IOException