How to capture the exit status of shell commands in Java?

I am creating a JUnit test file for my csvreader I am reading the contents of the CSV file and writing the contents to another file I want to use the diff utility to compare them. I want to use the exit state of diff to know whether the contents are the same Usually $? Gives the exit status, but I don't know how to capture it and use it in my code Who can help me in this regard?

That's what my code looks like

boolean hasSameContents = false;

    command="diff "+mp.get("directory")+"/"+fileName+" "+mp.get("outdir")+"/"+fileName;
    p= Runtime.getRuntime().exec(command);
    p.waitFor();

After that, I want to get the exit status and use it under the condition of if

if(exit_status==0)
     hasSameContents = true;
  else
     hasSameContents = false;

Even other suggestions are popular:)

Solution

Are you looking for process #exitvalue

String command = "diff "+mp.get("directory")+"/"+fileName+" "+mp.get("outdir")+"/"+fileName;
Process p = Runtime.getRuntime().exec(command);
p.waitFor();
int exitStatus = p.exitValue();

Don't forget that you should read the contents of InputStream. Even if you don't care, some processes will block (not complete) before reading the output buffer