com.jscape.inet.sftp.SftpException: cause: java.util.NoSuchElementException: no common elements found- JSCAPE Java library - linux

Question

I tried to connect and download a file from a Linux server but faced the following exception when connecting to the server using the jscape java library.
Code
package com.example.util;
import com.jscape.inet.sftp.Sftp;
import com.jscape.inet.ssh.util.SshParameters;
public class TestFTPManager
{
private static final String hostname = "mycompany.example.com";
private static final String username = "exampleuser";
private static final String password = "examplepassword";
private static final int port = 22;
private Sftp sftpClient;
public TestFTPManager()
{
this.sftpClient = new Sftp( new SshParameters(hostname, port, username, password ));
}
public void connect() throws Exception
{
this.sftpClient.connect();
}
public void setAscii() throws Exception
{
this.sftpClient.setAscii();
}
public void setBinary() throws Exception
{
this.sftpClient.setBinary();
}
public Sftp getSftpClient()
{
return sftpClient;
}
public void setSftpClient( Sftp sftpClient )
{
this.sftpClient = sftpClient;
}
public static void main(String[] args)
{
try
{
TestFTPManager sftpManager = new TestFTPManager();
sftpManager.getSftpClient().connect(); // Error
System.out.println( "Connection successful!" );
// download operation is done here.
sftpManager.getSftpClient().disconnect();
System.out.println( "Disconnection successful!" );
} catch (Exception e)
{
e.printStackTrace();
}
}
}
Error
com.jscape.inet.sftp.SftpException: cause: java.util.NoSuchElementException: no common elements found
at com.jscape.inet.sftp.SftpConfiguration.createClient(Unknown Source)
at com.jscape.inet.sftp.Sftp.connect(Unknown Source)
at com.jscape.inet.sftp.Sftp.connect(Unknown Source)
at com.example.util.TestFTPManager.main(TestFTPManager.java:54)
Caused by: com.jscape.inet.ssh.transport.TransportException: cause: java.util.NoSuchElementException: no common elements found
at com.jscape.inet.ssh.transport.AlgorithmSuite.<init>(Unknown Source)
at com.jscape.inet.ssh.transport.TransportClient.getSuite(Unknown Source)
at com.jscape.inet.ssh.transport.Transport.exchangeKeys(Unknown Source)
at com.jscape.inet.ssh.transport.Transport.exchangeKeys(Unknown Source)
at com.jscape.inet.ssh.transport.TransportClient.<init>(Unknown Source)
at com.jscape.inet.ssh.transport.TransportClient.<init>(Unknown Source)
at com.jscape.inet.ssh.SshConfiguration.createConnectionClient(Unknown Source)
at com.jscape.inet.ssh.SshStandaloneConnector.openConnection(Unknown Source)
... 4 more
Caused by: java.util.NoSuchElementException: no common elements found
at com.jscape.inet.ssh.types.SshNameList.getFirstCommonNameFrom(Unknown Source)
at com.jscape.inet.ssh.transport.AlgorithmSuite.a(Unknown Source)
at com.jscape.inet.ssh.transport.AlgorithmSuite.h(Unknown Source)
... 12 more
However, when I commented down the following lines (lines no 23,23,25) in the /etc/ssh/sshd_config file in the server. I could successfully connect and download the file from the server without any exceptions.
Question: How to get rid of getting this exception without commenting down (lines no 23,23,25) the /etc/ssh/sshd_config file in the server? I would appreciate having an explanation why I get this exception too.

Answer 1

If you are facing this issue please check the following findings.
I used JSCAPE (Java) library version 8.8.0. According to my understanding, this version is not supported some of the Ciphers and KexAlgorithms specified in the sshd_config file.
When you refer to the JSCAPE documentation, com.jscape.inet.sftp class contains what you need to set key exchanges, ciphers, macs and compressions if needed. Please click here to see the official documentation, there you can see how you can put these things into code.
However, the JSCAPE (Java) library that I use (version 8.8.0) does not contain these classes and methods to set key exchanges, ciphers, macs and compressions if needed.
One of the things you can try is to use the latest version of the JSCAPE library, but I doubt it is available for free.