Problem in copying the file

Question

i had created a frame in which iam getting a source file and then copies the file to certain location...the problem is when i copy a large file it is doing well for the first time but when the second time while iam copying exception occurs like this
Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space
iam using the code
public static void copy(File source, File dest) throws IOException {
     FileChannel in = null, out = null;
     try {         
          in = new FileInputStream(source).getChannel();
          out = new FileOutputStream(dest).getChannel();
          long size = in.size();
          MappedByteBuffer buf = in.map(FileChannel.MapMode.READ_ONLY, 0, size);
          out.write(buf);
     } finally {
          if (in != null)          in.close();
          if (out != null)     out.close();
    }how to solve this

Answer 1

Do you simply want to copy the file. Try, not using many non-instrictive data types, because these use many extra variables and you end up using a lot more memory than you would have req.
Eg-
public void copy(File source,File dest) throws IOException{
     FileInputStream fins=new FileInputStream(source);
     byte[]b=new byte[(int)fins.length()];
     fins.read(b);
     fins.close();
     FileOutputStream fos=new FileOutputStream(dest);
     fos.write(b);
     fos.close();
}This is code is not a solution, because here i am reading all file at once. This is basically to show you a method.
In real situation you can set the size of byte[]b to 1024, and loop util read(b); method returns -1.