question: public SecureShellAgent ( final String host , final int port , final String user , final Path privateKeyFileAbsolutePath ) throws AgentException { try { session = getSession ( host , port , user ) ; jsch . addIdentity ( privateKeyFileAbsolutePath . toString ( ) ) ; } catch ( Exception e ) { String errorMessage = format ( "Can't connect to host '%s@%s:%s' by using private key '%s'." , user , host , port , privateKeyFileAbsolutePath ) ; throw create ( errorMessage , e ) ; } }
target:  Create ssh session object and try to connect to remote host by using auth key. 