It seems like you are closing the output stream after writing each line. The
trick here is to keep the file  (output stream) open and close  it after write is
complete or in the finalize block.

For more details follow this:
java.sun.com/.../overview.html

wat u are asking for can easily done...using files...if u could go through the
documentation ...i wl give u a hint...try using random access files

The following code creates a RandomAccessFile to read the file  named
farrago.txt:
new RandomAccessFile("farrago.txt", "r");
And this one opens the same file for both reading and writing:
new RandomAccessFile("farrago.txt", "rw");

I like to learn java  and I am
learning.. Actually this is for one of my assignmnets.. the
thing is I have to submitthe assignmnet on friday. So I don't
hav much time to work on it. If you can help  me with my other
questions also that will be great help.