Error while casting to enumeration

Question

I am trying to combine 4 files into a single file,using SequenceInputStream and LinkedList as data structure.

My error is

Exception in thread "main" java.lang.ClassCastException: java.io.FileInputStream cannot be cast to java.util.Enumeration at faizal.Address.main(Address.java:21)

import java.io.*;

import java.util.*;



public class Address{
    public static void main(String[] args) throws Exception {
        FileInputStream f1 = new FileInputStream("E://Ass.java");
        FileInputStream f2 = new FileInputStream("E://Ass1.java");
        FileInputStream f3 = new FileInputStream("E://abc.txt");
        FileInputStream f4 = new FileInputStream("E://ad.txt");
        LinkedList al = new LinkedList();
        al.add(f1);
        al.add(f2);
        al.add(f3);
        al.add(f4);
        Collections.synchronizedList(al);
        Enumeration e = (Enumeration) al.element();
        SequenceInputStream sq = new SequenceInputStream((Enumeration<? extends InputStream>) al);
        int i = 0;
        while((i=sq.read())!=-1){
            System.out.print((char)i);
        }


    }
}

You can't just magically turn a `FileInputStream` into an `Enumeration` by casting it. — azurefrog, Dec 12 '15 at 05:00

score 0 · Answer 1 · edited May 23 '17 at 12:04

If I understand your goal: you have 4 files, you want to concatenate. Format inside files doesn't matter. The way you use is useless (sic), and cant work, because your program cant guess magicly what is inside.

Then, just :

read each one:

Reading a plain text file in Java

I suppose it is texte (txt, java) : just append to String, and write in one shot to a file, like this:

How do I create a file and write to it in Java?

or, write each one, and append to the file

How to append text to an existing file in Java

Error while casting to enumeration

1 Answers1