S3 can not include a folder

Hi,
I check the code:
if(bucket.indexOf("/") > 0){
throw new IllegalArgumentException("S3 Bucket field cannot contain any subdirectories. Bucket name only!");
}

I don't know why S3 Bucket can't contain any subdirectories, in our real case, We want to use the same S3 Bucket and create different folder under the same Bucket.

can you fix this issue?

Thanks
Danny