Java: Read File

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class ReadFileLineByLine {
    public static void main(String[] args) {
        String xfilename = "input.txt";
        try (BufferedReader xreader = new BufferedReader(new FileReader(xfilename))) {
            String xline;
            while ((xline = xreader.readLine()) != null) {
                System.out.println(line);
            }
            xreader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Read and write to file

here's a example that makes a copy of a file, by reading the file content char by char, then writing it out.

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

public class ReadWriteCopyFile {
     public static void main(String[] args) throws IOException {
         File xinputFile = new File("xinput.txt");
         File xoutputFile = new File("xoutput.txt");

         FileReader xreaderInput = new FileReader(xinputFile);
         FileWriter xwriterOutput = new FileWriter(xoutputFile);
         int xc;

         while ((xc = xreaderInput.read()) != -1)
            xwriterOutput.write(xc);

         xreaderInput.close();
         xwriterOutput.close();
     }
}