@@ -19,6 +19,7 @@
 import static com.google.cloud.RetryHelper.runWithRetries;
 import static java.util.concurrent.Executors.callable;
 
+import com.google.api.services.storage.Storage;
 import com.google.api.services.storage.model.StorageObject;
 import com.google.cloud.BaseWriteChannel;
 import com.google.cloud.RestorableState;
@@ -120,6 +121,12 @@ public void run() {
 // For completeness, this case is not possible because it would require retrying
 // a 400 status code which is not allowed.
 //
+// Case 7: remoteNextByteOffset==-1 && last == true
+// Upload is complete and retry occurred in the "last" chunk. Data sent was received by the service.
+//
+// Case 8: remoteNextByteOffset==-1 && last == false
+// Upload was completed by another client because this retry did not occur during the last chunk.
+//
 // Get remote offset from API
 long remoteNextByteOffset =
 getOptions().getStorageRpcV1().getCurrentUploadOffset(getUploadId());
@@ -154,7 +161,8 @@ && driftOffset < getChunkSize()) {
 // Continue to next chunk
 retrying = false;
 return;
-} else {
+} else if (localNextByteOffset < remoteNextByteOffset
+&& driftOffset > getChunkSize()){
 // Case 5
 StringBuilder sb = new StringBuilder();
 sb.append(
@@ -167,6 +175,13 @@ && driftOffset < getChunkSize()) {
 sb.append("remoteNextByteOffset: ").append(remoteNextByteOffset).append('\n');
 sb.append("driftOffset: ").append(driftOffset).append("\n\n");
 throw new StorageException(0, sb.toString());
+} else if (remoteNextByteOffset == -1 && last) {
+// Case 7
+retrying = false;
+return;
+} else if (remoteNextByteOffset == -1 && !last) {
+// Case 8
+throw new StorageException(0, "Resumable upload is already complete.");
 }
 }
 // Request was successful and retrying state is now disabled.

@@ -766,7 +766,7 @@ public long getCurrentUploadOffset(String uploadId) {
 response = httpRequest.execute();
 int code = response.getStatusCode();
 if (code == 201 || code == 200) {
-throw new StorageException(0, "Resumable upload is already complete.");
+return -1;
 }
 StringBuilder sb = new StringBuilder();
 sb.append("Not sure what occurred. Here's debugging information:\n");