Executing sudo using SSH "exec" channel in JSch

I am using file in which I passed below commands:

1. hostname
2. pwd
3. pbrun su - fclaim
4. whoami
5. cd ..
6. pwd

Ad the Java code below:

for (String command1 : commands) {

    Channel channel=session.openChannel("exec");
    ((ChannelExec)channel).setCommand(command1);

    in=channel.getInputStream();
    channel.connect();
    byte[] tmp=new byte[1024];
    while(true){
      while(in.available()>0){
        int i=in.read(tmp, 0, 1024);
        if(i<0)
            break;
        System.out.println(new String(tmp, 0, i));
      }
      if(channel.isClosed()){
        break;
      }
    }
    channel.setInputStream(null);
    channel.disconnect();
}

But I'm getting this output:

1. some hostname
2. /home/imam
3. missing output
4. imam
5. missing output
6. /home/imam

Your code executes each command in an isolated environment. So your second whoami does not run within pbrun su, as you probably hoped for.

The pbrun su executes a new shell.

To provide a command to the shell you either:

• specify the command on su command-line, like the official JSch Sudo.java example shows:

  ((ChannelExec)channel).setCommand("pbrun su - fclaim -c whoami");
  

• or feed the command to the shell using its standard input:

  OutputStream out = channel.getOutputStream();
  out.write(("whoami\n").getBytes());
  

  See also:
  Executing multiple bash commands using a Java JSch program after sudo login and
  Running command after sudo login.

In general, I recommend the first approach as it uses a better defined API (command-line argument).