今天我照着<thinking in java 2th>的p594页做了以下程序,编译时突然就弹出一个"
java virtual machine launcher"的对话框,内容为:"could not find the main class.program well exit"  但是编译其他的java文件就没事,对了,我用的编译器为eclipse,在command中用javac命令也是出现同样的提示,诧异中........


import java.io.*;
public class IOStreamDemo {
// throw exceptions to console:
    public static void main(String[] args) throws IOException {
     // 1. reading input by lines:
     BufferedReader in = new BufferedReader(
         new FileReader("IOStreamDemo.java"));
     String s, s2 = new String();
     while((s = in.readLine()) != null);
         s2 += s + "\n";
     in.close();
    
        // 1b. reading standard input:
        BufferedReader stdin = new BufferedReader(
            new InputStreamReader(System.in));
        System.out.print("Enter a line:");
        System.out.println(stdin.readLine());
        
        // 2. Input from memory:
        StringReader in2 = new StringReader(s2);
        int c;
        while((c = in2.read()) != -1);
            System.out.print((char)c);
            
        // 3. format memory input:
        try {
         DataInputStream in3 = new DataInputStream(
             new ByteArrayInputStream(s2.getBytes()));
         while(true)
             System.out.print((char)in3.readByte());
             } catch(EOFException e) {
              System.err.println("End of Stream");
             }
             
        // 4. file output:
        try {
         BufferedReader in4 = new BufferedReader(
             new StringReader(s2));
         PrintWriter out1 = new PrintWriter(
             new BufferedWriter(
                 new FileWriter("IODemo.out")));
         int lineCount = 1;
         while((s = in4.readLine()) != null)
             out1.println(lineCount++ + ": " + s);
             out1.close();
             } catch(EOFException e) {
                 System.err.println("End of stream");
             }
             
        // 5. storing & recovering data
        try {
         DataOutputStream out2 = new DataOutputStream(
             new BufferedOutputStream(
                 new FileOutputStream("Data.txt")));
         out2.writeDouble(3.14159);
         out2.writeChars("that was pi\n");
         out2.writeBytes("that was pi\n");
         out2.close();
         DataInputStream in5 = new DataInputStream(
             new BufferedInputStream(
                 new FileInputStream("Data.txt")));
         BufferedReader in5br = new BufferedReader(
             new InputStreamReader(in5));
         // must use DataInputStream for data:
         System.out.println(in5.readDouble());
         // can now use the "proper" readLine():
         System.out.println(in5br.readLine());
         // but the line comes out funny.
         // the one created with writeBytes is ok:
         System.out.println(in5br.readLine());
           }catch(EOFException e) {
            System.err.println("end of stream");
           }
           
        // 6. reading/writing random access files
        RandomAccessFile rf = new RandomAccessFile("rtest.dat","rw");
        for(int i = 0; i < 10; i++)
            rf.writeDouble(i*1.414);
            rf.close();
            
            rf = new RandomAccessFile("rtest.dat","rw");
            rf.seek(5*8);
            rf.writeDouble(47.0001);
            rf.close();
            
            rf = new RandomAccessFile("rtest.dat","rw");
            for(int i = 0; i < 10; i++)
                System.out.println("Value" + i + ": " + rf.readDouble());
            rf.close();
    }
}