I have an applet that sends a text request to a servlet that (via a JNDI lookup) makes a database connection and retrieves a large ammount of information. After a succession of queries, a custom object (implementing the serialized interface) is populated (mostly made up of Strings and Vectors)
and this data is sent up to the applet for user to manipulate before a request is made to save. I am receiving an EOFException / NullPointerException inside the applet randomly. Have done this process before and never run into this problem, but I have never moved this much data at once serialized (~300-500k).

Error retrieving CSTS_queryRunner data: java.io.EOFException: Expecting code

Error retrieving blank CSTS_projectHeader data: java.lang.NullPointerException



Code attached below, any comments would be appreciated:


APPLET:

			

			Object o = new Object();
			

			

			try {
			

			

			String arg_string = "QUERY_STRING=" + URLEncoder.encode(query_string) + "&EXPECTED_SIZE=" +
			

			expected_size;
			

			

			URL destination = new URL( servlet_location );
			

			

			URLConnection con = destination.openConnection();
			

			

			con.setDoInput(true);
			

			

			con.setDoOutput(true);
			

			

			con.setUseCaches(false);
			

			

			con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
			

			

			DataOutputStream out = new DataOutputStream( con.getOutputStream() );
			

			

			out.writeBytes( arg_string );
			

			

			out.flush();
			

			

			out.close();
			

			

			ObjectInputStream in = new ObjectInputStream( con.getInputStream() );
			

			

			o = in.readObject();
			

			

			try {
			

			

			query_output = (Vector)o;
			

			

			} catch( ClassCastException cast_e ) {
			

			

			if( o instanceof java.lang.String ) {
			

			

			System.out.println( (String)o );
			

			

			} else {
			

			

			throw cast_e;
			

			

			}
			

			

			} finally {
			

			

			in.close();
			

			

			}
			

			

			} catch( Exception e ) {
			

			

			System.out.println("Error retrieving CSTS_queryRunner data: " + e.toString());
			

			

			}
			

			

		

			

			out = new ObjectOutputStream( res.getOutputStream() );
			

			

			out.reset();
			

			

			

			//Lookup the JDBC connection object from session
			

			try {
			

			

			context = new InitialContext();
			

			

			source = (DataSource)context.lookup("java:comp/env/jdbc/CSTS_CON");
			

			

			connection = source.getConnection( (String)session.getValue("CSTS_USERNAME"), (String)session.getValue("CSTS_PASSWORD") );
			

			

			} catch( Exception e ) {
			

			

			throw new Exception( "Error while retrieving DB Connection from session: " + e.toString() );
			

			

			}
			

			

			

			// ########################################################################
			

			query_string = req.getParameter("QUERY_STRING");
			

			

			String tmp_expected_size = req.getParameter("EXPECTED_SIZE");
			

			

			int expected_size = 10;
			

			

			try {
			

			

			expected_size = (new Integer(tmp_expected_size)).intValue();
			

			

			} catch(
			

			NumberFormatException num_e ) { }
			

			

			Statement stmt = connection.createStatement();
			

			

			ResultSet rs = stmt.executeQuery( query_string );
			

			

			Vector v = new Vector( expected_size );
			

			

			int col_count = (rs.getMetaData()).getColumnCount();
			

			

			while( rs.next() ) {
			

			

			String data[] = new String[ col_count ];
			

			

			for( int i=1; i
			<=col_count; i++ ) {
			

			

			try {
			

			

			data[i-1] = new String( rs.getString(i) );
			

			

			} catch( Exception junk_e ) {
			

			

			data[i-1] = new String("");
			

			

			}
			

			

			}
			

			

			v.addElement( data );
			

			

			}
			

			

			out.writeObject( v );
			

			

			out.flush();
			

			

			rs.close();
			

			

			stmt.close();
			

			

			} catch( Exception e ) {
			

			out.writeObject( new String("CSTS_queryRunner: " + e.toString()) );
			

			

			System.err.println( "*****CSTS Application Error: " + (new java.util.Date()) + " *****" );
			

			

			System.err.println( ">>>>>Running query: " + query_string );
			

			

			e.printStackTrace();
			

			

			System.err.println( "***************************************************" );
			

			

			} finally {
			

			out.close();
			

			

			try {
			

			

			connection.close();
			

			

			} catch( Exception e ) {
			

			

			System.err.println( "*****CSTS Application Error: " + (new java.util.Date()) + " *****" );
			

			

			e.printStackTrace();
			

			

			System.err.println( "***************************************************" );
			

			

			}
			

			} //end global try