Garbage Collection - OutputStream

["albartell" <albartell@xxxxxxxxx>]

Hi all,
 
I recently wrote some code against a J2ME device that takes image data
received via a call-back method and sends it to a remote server via an http
OutputStream object. I have never really paid a ton of attention to garbage
collection because Java has always done it for me, but I am in a memory
constrained runtime (32MB) and memory management is of the highest order.
 
My question relates to the below asyncMethod(...) that receives in 65k
chunks of data, copies it into a new byte array, and writes it the the
HttpURLConnection's outStream object using write() which is immediately
followed by a flush. After the "return false;" statement the newCopy byte
array is no longer in scope and therefore ready to be garbage collected
(from what I understand of GC). The outStream object is defined globablly
and is NOT out of scope after each asyncMethod(...) call. Being that I
called the outStream.flush() method I am assuming it would not be holding
onto the 65k of image data for each call-back made to asyncmethod(...).
 
The problem:
As you can see I have a output statement that calls on
Runtime.getRuntime().freeMemory() used to see how much memory is available
at each asyncMethod(...) execution. The freeMemory() return value starts out
at about 15MB and continues to go down to 2MB and at that point the JRE
running on the device seems to think it is time to run GC and the
freeMemory() is bumped back up to 15MB.  I have attempted to put in
System.gc() statements to do my own garbage collection, but that doesn't
seem to address the problem (or rather it doesn't affect the value I am
getting from freeMemory()).
 
Final question, I promise :-)
 
So, is the outStream holding onto data somehow? Should I be looking at how
this company wrote the JRE for their device(assuming they would have to
create their own because it isn't running on a standard OS of any kind)?
 
I have looked at a bunch of GC articles hoping to find my answers, but have
not yet found one that addresses the specific question I have.
 
Thanks for any input,
Aaron Bartell
 
public class ResourceReader {
 
    HttpURLConnection conn;
    OutputStream outStream;
 
  public class ResourceListener extends OperationResultAdapter {
        public boolean asyncMethod(int blockNo, OutParamAcquireResource oar)
{
 
                Log.out("oar.data.length=" + oar.data.length + "  freemem="
+ Runtime.getRuntime().freeMemory() + "  blockNo=" + blockNo);
                    byte[] newCopy = new byte[oar.data.length];
                    System.arraycopy(oar.data, 0, newCopy, 0,
oar.data.length);
                    outStream.write(newCopy);
                    outStream.flush();
            return false;
        }
    }
  }
 
}