PanelTest.java

import java.io.*;
public class LineTest {
  private File file;
  public LineTest(File file) throws Exception{
    this.file=file;
    String content=putLines();
    write(content);
  }
  public String putLines(){
    try{
      String line = null;
      FileReader reader=new FileReader(file);
      BufferedReader br=new BufferedReader(reader);
      StringBuffer buffer=new StringBuffer();
      int lineNumber=1;
      while ((line = br.readLine()) != null){
        buffer.append(lineNumber);
        buffer.append("\t");
        buffer.append(line);
        buffer.append("\n");
        lineNumber++;
      }
      br.close();
      return buffer.toString();
    }catch(FileNotFoundException e){
      e.printStackTrace();
      return null;
    }
    catch(IOException ei){
      ei.printStackTrace();
      return null;
    }
  }
  private void write(String content) throws Exception{
    String parent=file.getParent();
    FileWriter writer=new FileWriter(parent+"/"+"line_"+file.getName(),false);
    writer.write(content);
    writer.close();
  }
  public static void main(String[] args){
    try{
      File file=new File("/Users/zaferteker/Private/Books/Documents/HelloWorld.java");
      new LineTest(file);
    }catch(Exception e){
      e.printStackTrace();
    }
  }
}