com.dropbox.core.NetworkIOException: Error writing request body to server

I've created following script to upload all files from folder.

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import com.dropbox.core.DbxException;
import com.dropbox.core.DbxRequestConfig;
import com.dropbox.core.v2.DbxClientV2;
import com.dropbox.core.v2.users.FullAccount;
import com.dropbox.core.v2.files.FileMetadata;
import com.dropbox.core.v2.files.Metadata;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.File;

public class DriveQuickstart {
private static final String ACCESS_TOKEN = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
private static final String backupDir="WE0627";

public static void main(String args[]) throws DbxException {
// Create Dropbox client
DbxRequestConfig config = DbxRequestConfig.newBuilder("dropbox/java-tutorial").build();
DbxClientV2 client = new DbxClientV2(config, ACCESS_TOKEN);
FullAccount account = client.users().getCurrentAccount();
System.out.println(account.getName().getDisplayName());

try{
File dataFolder = new File("data");
if(dataFolder != null){
File[] listOfDataDirFiles = dataFolder.listFiles();
if(listOfDataDirFiles != null ){
for(File f: listOfDataDirFiles){
FileMetadata metadata = client.files().uploadBuilder("/TT Screenshots/"+backupDir+"/"+f.getName()).uploadAndFinish(new FileInputStream(f));
}
}
}
}catch(Exception e){
e.printStackTrace();
}
}
}

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script is working fine with smaller files(tested with 3 4 test.txt) but it uploads only 67 files from N numbers of files, which are 250MB on average in size.

 

it's showing following exception 

com.dropbox.core.NetworkIOException: Error writing request body to server
at com.dropbox.core.DbxUploader.uploadAndFinish(DbxUploader.java:123)
at com.dropbox.core.DbxUploader.uploadAndFinish(DbxUploader.java:96)
at com.dropbox.core.v2.DbxUploadStyleBuilder.uploadAndFinish(DbxUploadStyleBuilder.java:92)
at DriveQuickstart.main(DriveQuickstart.java:56)
Caused by: com.dropbox.core.util.IOUtil$WriteException: Error writing request body to server
at com.dropbox.core.util.IOUtil.copyStreamToStream(IOUtil.java:61)
at com.dropbox.core.util.IOUtil.copyStreamToStream(IOUtil.java:68)
at com.dropbox.core.util.IOUtil.copyStreamToStream(IOUtil.java:43)
at com.dropbox.core.http.HttpRequestor$Uploader.upload(HttpRequestor.java:103)
at com.dropbox.core.DbxUploader.uploadAndFinish(DbxUploader.java:118)
... 3 more
Caused by: java.io.IOException: Error writing request body to server
at sun.net.www.protocol.http.HttpURLConnection$StreamingOutputStream.checkError(HttpURLConnection.java:3597)
at sun.net.www.protocol.http.HttpURLConnection$StreamingOutputStream.write(HttpURLConnection.java:3580)
at com.dropbox.core.util.ProgressOutputStream.write(ProgressOutputStream.java:27)
at com.dropbox.core.util.IOUtil.copyStreamToStream(IOUtil.java:59)
... 7 more

 

Please advice on this. Thanks