关于RandomAccessFile的seek和skipBytes

[StilesYu]

package Day07;

import java.io.IOException;
import java.io.RandomAccessFile;


public class RandomAccessFileDemo2 {

	public static void main(String[] args) throws IOException {
		RandomAccessFile raf
			=new RandomAccessFile("raf.txt","rw") ;
	
		String str="I read a book in library";
		byte[] data=str.getBytes("UTF-8");
		
		
	    raf.seek(0);
	    
	    byte [] d=new byte[100];
	    int len=raf.read(d);
	    String s=new String(d, 0, len,"UTF-8");
	    System.out.println(s);
	   
	    raf.seek(0);
	    
            int a=raf.skipBytes(0);
	    System.out.println(raf.getFilePointer());
	    
	    raf.seek(0);
	    
	    System.out.println(raf.getFilePointer());
	    
	    byte [] d1=new byte[100];
	    int len1=raf.read(d1);
	    String s1=new String(d1, 1, len1,"UTF-8");
	    System.out.println(s1);
	    raf.close();
	    
	}
}

代码如下
输出：I read a book in library,You swimming in sea
0
0
read a book in library,You swimming in sea

看了下skipBytes（）的源代码

public int skipBytes(int n) throws IOException {
        long pos;
        long len;
        long newpos;

        if (n <= 0) {
            return 0;
        }
        pos = getFilePointer();
        len = length();
        newpos = pos + n;
        if (newpos > len) {
            newpos = len;
        }
        seek(newpos);

        /* return the actual number of bytes skipped */
        return (int) (newpos - pos);
    }

Question：skipBytes（0） 输出的是0 指针应该是在0位置 读取时候应该是完整的 I am a Java beginners
但是为什么读取时候变成了 am a Java beginnersx（x为乱码） 指针到了1位置 我通过seek（0） 想把指针
重新调到0位置 却发现原来的1位置变成了0

刚学JAVA 可能问题有点弱智 请见谅