script to make a new Indentation of any code file;

Indent.java

import java.util.List;
import java.util.ArrayList;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.PrintWriter;
import java.io.IOException;

class Indent {

    static List<String> records = new ArrayList<String>();
    public static void main(String[] args) {
        readFile("./ScanFragment.java");
        System.out.println();

        try {
            PrintWriter writer = new PrintWriter("./New.java");
            for (String line : records) {
                writer.println(line); 
            }
            writer.close();
        } catch (IOException e) {
            // do something
        }
    }

    /**
     * Open and read a file, and return the lines in the file as a list
     * of Strings.
     */
    static private List<String> readFile(String filename) {
        try {
            BufferedReader reader = new BufferedReader(new FileReader(filename));
            String line;
            
            while ((line = reader.readLine()) != null) {
                int spaces = 0;
                while (line.startsWith(" ")) {
                    line = line.replaceFirst(" ", "");
                    spaces++;
                }
                records.add(" ".repeat(spaces * 2) + line);
            }
            reader.close();
            return records;
        } catch (Exception e) {
            System.err.format("Exception occurred trying to read '%s'.", filename);
            e.printStackTrace();
            return null;
        }
    }
}