Java Program to remove Blank lines from a given file

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.Scanner;


public class RemoveBlankLines {


    public static void main(String[] args) throws Exception{
   
        Scanner s = new Scanner(System.in);
        System.out.println("Enter source file name");
        String srcfile = s.nextLine();
       
        File src = new File(srcfile);
        FileReader fr = new FileReader(src);
        BufferedReader br = new BufferedReader(fr);
       
        File trg = new File("tempfile.txt");
        FileWriter fw = new FileWriter(trg);
       
        String line;
        line = br.readLine();
       
        while(line!=null) {
            if(line.length() > 0)
                fw.write( line + "\n");
            line = br.readLine();
        }
                fw.close();
                fr.close();
                src.delete();
                trg.renameTo(src);
    }
   
}