以下程序的运行结果是( )。
import java.io.*;
public class E {
public static void main(String args]) {
int n=-1;
File f =new File("hello.txt");
byte ] a="abcd".getBytes();
try{ FileOutputStream out=new FileOutputStream(f);
out.write(a);
out.close();
FileInputStream in=new FileInputStream(f);
byte ] tom= new byte3];
int m = in.read(tom,0,3);
System.out.println(m);
String s=new String(tom,0,3);
System.out.println(s);
m = in.read(tom,0,3);
System.out.println(m);
s=new String(tom,0,3);
System.out.println(s);
}
catch(IOException e) {}
}
}