Could sshj check sftp storage size?

Hi there,

I want to check the size of server sftp, but when I go through those 3 methods,

>
System.out.println("att size " + sftpClient.size("/"));
System.out.println("att size " + sftpClient.lstat("/").getSize());
System.out.println("att size " + sftpClient.stat("/").getSize());
>
they all return with 4096, am i calling the wrong method? or what's the right method to get the sftp server size?

Thanks in advance.