These clients from https://commons.apache.org/proper/commons-net/[Apache commons net] libraries are based on unencrypted protocols and are not recommended:
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TelnetClient telnet = new TelnetClient(); // Sensitive
FTPClient ftpClient = new FTPClient(); // Sensitive
SMTPClient smtpClient = new SMTPClient(); // Sensitive
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== Compliant Solution
Use instead these clients from https://commons.apache.org/proper/commons-net/[Apache commons net] and http://www.jcraft.com/jsch/[JSch/ssh] library:
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JSch jsch = new JSch(); // Compliant
FTPSClient ftpsClient = new FTPSClient(true); // Compliant
SMTPSClient smtpsClient = new SMTPSClient(true); // Compliant