using RMAN commands in Java

I tried to launch thow Runtime processor RMAN commands, but after execution "RMAN" next commands cannot be executed, here is my code, what is the problem?
ArrayList<String> cmd=new ArrayList<String>();
cmd.add("rman");
cmd.add("connect target/");
cmd.add("exit");

for (int i=0;i<cmd.size();i++){
Process proc=rt.getRuntime().exec(cmd.get(i).toString());
BufferedReader br=new BufferedReader(new InputStreamReader(proc.getInputStream()));
String line=br.readLine();
while(line!=null)
{
line=br.readLine();
System.out.println(line);
}

Go through all the sections of this article and implement ALL the recommendations.
When Runtime.exec() won't - JavaWorld

db

unfortunately your link cannot be open, there is 403 Error, could you give me another one, thank you

Opens fine for me. Try again.

db

yes, now it's opens