# (Java) #IP1 Fails But Output Looks Ok

**URL:** <https://forum.codecrafters.io/t/java-ip1-fails-but-output-looks-ok/9992>\
**Category:** Challenges\
**Tags:** challenge:shell\
**Created:** [May 4, 2025, 10:12pm UTC](https://forum.codecrafters.io/t/java-ip1-fails-but-output-looks-ok/9992 "2025-05-04T22:12:12Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![BHSDuncan](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/bhsduncan/32/10135_2.png) [@BHSDuncan](https://forum.codecrafters.io/u/BHSDuncan)\
**Post date:** [May 4, 2025, 10:12pm UTC](https://forum.codecrafters.io/t/java-ip1-fails-but-output-looks-ok/9992/1 "2025-05-04T22:12:12Z")

</div>

I’m stuck on Stage #IP1.

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

```java
    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:

```auto
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!

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<div class="post-metadata">

**Author:** ![andy1li](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/andy1li/32/10_2.png) [@andy1li](https://forum.codecrafters.io/u/andy1li)\
**Post date:** [May 4, 2025, 10:53pm UTC](https://forum.codecrafters.io/t/java-ip1-fails-but-output-looks-ok/9992/3 "2025-05-04T22:53:58Z")

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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.

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<div class="post-metadata">

**Author:** ![BHSDuncan](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/bhsduncan/32/10135_2.png) [@BHSDuncan](https://forum.codecrafters.io/u/BHSDuncan)\
**Post date:** [May 4, 2025, 11:51pm UTC](https://forum.codecrafters.io/t/java-ip1-fails-but-output-looks-ok/9992/4 "2025-05-04T23:51:32Z")

</div>

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!

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<div class="post-metadata">

**Author:** ![andy1li](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/andy1li/32/10_2.png) [@andy1li](https://forum.codecrafters.io/u/andy1li)\
**Post date:** [May 5, 2025, 12:26am UTC](https://forum.codecrafters.io/t/java-ip1-fails-but-output-looks-ok/9992/5 "2025-05-05T00:26:26Z")

</div>

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

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<div class="post-metadata">

**Author:** ![system](https://canada1.discourse-cdn.com/flex003/uploads/codecrafters/original/3X/7/0/700657133935c15703e22c7c8870394f6e6dc27d.svg) [@system](https://forum.codecrafters.io/u/system)\
**Post date:** [May 10, 2025, 12:27am UTC](https://forum.codecrafters.io/t/java-ip1-fails-but-output-looks-ok/9992/6 "2025-05-10T00:27:19Z")

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