Question

I’m trying to run this code taken from Sun Java site (I didn’t copy it, Looked at it and wrote it as it would help me to remember the code).

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class CharEx{
    FileReader inputStream = null;
        FileWriter outputStream = null;

    public static void main(String args[]) throws IOException{
        FileReader inputStream = null;
        FileWriter outputStream = null;

        try{
            inputStream = FileReader("xanadu.txt");
            outputStream = FileWriter("out.txt");
            int c;
            while ((c = inputStream.read()) != -1){
                outputStream(c);
            } 
        }
        finally{
            if(inputStream !=null){
                inputStream.close();
            }
            if(outputStream !=null){
                outputStream.close();
            }

        }
    }
}

But I’m getting follwing error.

D:\Java>javac CharEx.java
CharEx.java:14: cannot find symbol
symbol  : method FileReader(java.lang.String)
location: class CharEx
                        inputStream = FileReader("xanadu.txt");
                                      ^
CharEx.java:15: cannot find symbol
symbol  : method FileWriter(java.lang.String)
location: class CharEx
                        outputStream = FileWriter("out.txt");
                                       ^
CharEx.java:18: cannot find symbol
symbol  : method outputStream(int)
location: class CharEx
                                outputStream(c);
                                ^
3 errors

From the message I think that the system is looking for FileReader inside java.lang whereas it should look for it inside java.io.* :((

Can someone help me where I’m getting wrong?

PS: I’m on JDK 1.5.

Answer 1

You’re trying to instantiate a FileReader and a FileWriter (i.e. create objects of those types).

To do that you need to use the new keyword:

inputStream = new FileReader("xanadu.txt");
outputStream = new FileWriter("out.txt");

By leaving out the new the code looks like a method call, so the compiler looks for a method named FileReader (and FileWriter) and doesn’t find it, which it tells you in a somewhat strange, but surprisingly clear language.

Hint: “symbol” is what a compiler calls a “name”. That name can be of a class, method, variables, … The exact problem can be found when checking the “symbol: “line. It tells you that the compiler looks for a method called FileReader that takes a String parameter:

CharEx.java:14: cannot find symbol
symbol  : method FileReader(java.lang.String)