File Channel Problem

Question

I have written a small method, that converts file content to CharSequence. For some reason it maintains a lock on the file. After calling CharSequenceFromFile method I cannot delete the file.
Obviously there is something that I don't understand something about FileChannel. Any help will be appretiated, thanks for ur time.
import java.io.*;
import java.nio.*;
import java.util.*;
import java.util.regex.*;
import java.nio.channels.*;
import java.nio.charset.*;
public class RegExTest {
     public static void main (String args[])throws Exception {
          CharSequence charSequence = CharSequenceFromFile("f.txt");
          File f = new File("f.txt");
          System.out.println("del"+ f.delete()); //prints false
     public static CharSequence CharSequenceFromFile(String filename) throws IOException {
          FileInputStream fis = new FileInputStream(filename);
          FileChannel fc = fis.getChannel();
          ByteBuffer bbuf = fc.map(FileChannel.MapMode.READ_ONLY,0, (int)fc.size());
          CharBuffer cbuf = Charset.forName("8859_1").newDecoder().decode(bbuf);
          fc.close();
          fis.close();
          return cbuf;
} PS: can it be a java bug?

Answer 1

The Java API v1.4.1 states the following about MappedByteBuffers :
'A mapped byte buffer and the file mapping that it represents remain valid until the buffer itself is garbage-collected.'
See the comments in code below...
import java.io.*;
import java.nio.*;
import java.util.*;
import java.util.regex.*;
import java.nio.channels.*;
import java.nio.charset.*;
public class RegExTest {
public static void main (String args[])throws
Exception {
CharSequence charSequence =
= CharSequenceFromFile("f.txt");
          File f = new File("f.txt");
System.out.println("del"+ f.delete()); //prints
s false
public static CharSequence
CharSequenceFromFile(String filename) throws
IOException {
FileInputStream fis = new
w FileInputStream(filename);
          FileChannel fc = fis.getChannel();
ByteBuffer bbuf =
= fc.map(FileChannel.MapMode.READ_ONLY,0,
(int)fc.size());
CharBuffer cbuf =
=
Charset.forName("8859_1").newDecoder().decode(bbuf);
          fc.close();
          fis.close();// add these lines below it will start working
          bbuf.clear();
          bbuf = null;
          System.gc();
// till here
          return cbuf;
PS: can it be a java bug?
NOT A BUG