Just map the binary to the content of a filedocument. If it is base64 encoded you may want to use the community commons Base64DecodeToFile.
I am using above micro flow for saving the file but the file is saving twice. Is this is the correct way to save the file.
Created Variable with Base64 encoded string ,
created NewDocument (Document is the file entity) object and using variable as encoded value and NewDocuments object as target file in java action.
The event is expecting Binary and File needs to be stored in contents(Binary) attribute of Documents(File entity)