(Java) #IP1 Fails But Output Looks Ok

Challenges
1

I’m stuck on Stage #IP1.

I’ve tried the following method to execute an external command:

    List<String> argsWithCommandName = new ArrayList<>(arguments);
    argsWithCommandName.addFirst(commandName);
    
    ProcessBuilder processBuilder = new ProcessBuilder(argsWithCommandName);
    
    try {
      Process process = processBuilder.start();
      process.waitFor();
      
      String output = inputStreamToString(process.getInputStream());
      
      System.out.println(output);
    } catch (Exception e) {
    }

Here are my logs:

remote: [compile] Compilation successful.
remote:
remote: Debug = true
remote:
remote: [tester::#IP1] Running tests for Stage #IP1 (Run a program)
remote: [tester::#IP1] [setup] export PATH=/tmp/baz:$PATH
remote: [tester::#IP1] [setup] Available executables:
remote: [tester::#IP1] [setup] - custom_exe_9420
remote: [tester::#IP1] Running ./your_program.sh
remote: [your-program] $ custom_exe_9420 David
remote: [your-program] Program was passed 2 args (including program name).
remote: [your-program] Arg #0 (program name): custom_exe_9420
remote: [your-program] Arg #1: David
remote: [your-program] Program Signature: 3357538634
remote: [tester::#IP1] Expected prompt ("$ ") but received ""
remote: [your-program] $
remote: [tester::#IP1] Assertion failed.
remote: [tester::#IP1] Test failed

I don’t understand why my output would show the proper prompt but the tester says it isn’t there. Maybe it’s something with how Process handles streams?

Thank you!

3

Hey @BHSDuncan, it’s common for an extra newline to trigger the error Expected prompt ("$ ") but received "".

Keep in mind that System.out.println() automatically appends a newline, which can cause this error.

4

I feel like a bit of a tool for missing that. It was a poor assumption on my part to dump the output with println. Thank you for the sanity check! That’s what I get for looking at code for too long.

Enjoying your challenges. Thanks again for the help!

1 Like
5

No worries at all! It happens to the best of us. Feel free to reach out anytime you get stuck again.

1 Like