Problem in flushing an Object - ObjectOutputzStream

Question

Hi
I have the following code, which writes a table data into a file.
FileOutputStream outFile = new FileOutputStream(fileName);
ObjectOutputStream out = new ObjectOutputStream(outFile);
while(rs.next())
ArrayList a = new ArrayList();
a.add(rs.getObject(1));
a.add(rs.getObject(2));
out.writeObject(a);
out.flush();
}If the rs.size is too big then it results in out of memory exception due to arraylist being created everytime.
In the above code I can see the object writen into file everytime I call flush.
but when I change the code to the following
FileOutputStream outFile = new FileOutputStream(fileName);
ObjectOutputStream out = new ObjectOutputStream(outFile);
ArrayList a = new ArrayList();
while(rs.next())
a.add(rs.getObject(1));
a.add(rs.getObject(2));
out.writeObject(a);
out.flush();
a.clear();
}Here I dont see the object written into the file when I call flush. At the end of loop It writes only the first row of the table and null for rest of the records.
The problem I think is due the arraylist that still has reference in the code, so it is not being writen into the stream.Can anybody give info about flushing the object that is still referred in the code?

Answer 1

You will need to do an out.reset() before your out.write() because and ObjectOutputStream will cache the array list referenced by 'a' the first time it is written and then just write a reference to it after that. The reset() clears the cache.
Note - you might also want to do a clear() on the array list before adding the two values as it will get bigger and bigger and bigger.
Message was edited by:
sabre150