RandomAccessFile output = null;
String customizedChunkSize = null;
customizedChunkSize = System.getProperty("com.amazonaws.services.glacier.transfer.downloadChunkSizeInMB");
DescribeJobResult describeJobResult = glacier.describeJob(new DescribeJobRequest(accountId, vaultName, jobId));
archiveSize = describeJobResult.getArchiveSizeInBytes();
if (customizedChunkSize != null) {
try {
chunkSize = Long.parseLong(customizedChunkSize) * 1024 * 1024;