File contains a path separator

Processing for Android
10

Well, I don’t know, how I did it, but the folowing code works:

import processing.sound.*;

String filePath = "/sdcard/Sketchbook/VisualizerProject/data/song.mp3";

void setup(){
  stealFile(filePath, "song.mp3");
  SoundFile sf = new SoundFile(this, /*dataPath("song.mp3")*/filePath);
  sf.play();
}

void draw(){
  background(0);
}

boolean stealFile(String from, String filename){
  println("Stealing file \"" + from + "\"...");
  if(!(new File(from).exists())){
    println("   Fail: Input path invalid...");
    return false;
  }
  BufferedReader reader;
  PrintWriter writer;
  try{reader = createReader(from);}
  catch(Exception e){
    println("   Fail: Reader couldn't be created...");
    e.printStackTrace();
    return false;
  }
  try{writer = createWriter(dataPath(filename));}
  catch(Exception e){
    println("   Fail: Writer couldn't be created...");
    e.printStackTrace();
    return false;
  }
  
  while(true){
    String l;
    try{l = reader.readLine();}
    catch(Exception e){continue;}
    if(l == null) break;
    writer.println(l);
  }
  
  try{
    reader.close();
  }
  catch(Exception e){
    println("Reader couldn't be closed");
  }
  writer.flush();
  writer.close();
  
  println("    Success: File \"" + from + "\" succesfilly stolen and copied as \"" + filename + "\"."); 
  return true;
}