Java tutorial
//package com.java2s; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.ObjectOutput; import java.io.ObjectOutputStream; import java.util.ArrayList; public class Main { public static synchronized void writeArrayListToFile(ArrayList<double[]> x, String filename) { // double []x = {1,2,4}; // String filename = "data.dat"; ObjectOutput out = null; try { out = new ObjectOutputStream(new FileOutputStream(new File(filename))); out.writeObject(x); out.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } }