Add Java as a supported output language

[jarsh921]

Follows the exact same pattern as python/javascript/typescript(/go):

• New prompt partial (prompts/partials/_language_java.md): uses java.net.http.HttpClient (built into the JDK since 11, no HTTP library dependency) and Gson for JSON (the JDK has no built-in JSON support), packaged as a minimal Maven project with exec-maven-plugin so it runs with a single command. Same auth-hardcoding/refresh guidance as the other languages. Also calls out a Java-specific naming detail: the generated file is named api_client.java (this generator's lowercase convention), so the top-level class is named ApiClient but declared package-private (no public modifier) - a public class's filename must exactly match its class name, and a package-private one doesn't have that restriction while compiling and running identically.
• base_engineer.py: added "java" to _OUTPUT_LANGUAGE_EXTENSIONS (.java), _get_language_name() ("Java"), _get_run_command() ("mvn -q compile exec:java"), and _get_auto_output_files() (pom.xml, always included for Java - unlike Go/JS's conditional dependency files, Gson is a hard requirement here since there's no stdlib JSON alternative, matching typescript's "always" precedent instead).
• cli.py: added Java to the interactive output_language config picker.
• Updated the three docstrings/comments that listed the language set (config.py, engineer.py, prompts/init.py) and README.md's output language line.
• Tests: mirrored the existing per-language test pattern in test_base_engineer.py (extension, run command, prompt content) and test_prompts.py (partial loading) for Java.

Caught and fixed one real bug before this counts as done: my first draft of the partial included a literal { ... } in prose describing the class declaration, which crashed load()'s str.format_map() with a KeyError (it treats any {...} in the template as a placeholder to substitute, not just the documented {run_command}-style ones) - confirmed against the other partials that none of them contain a literal brace anywhere, for the same reason. Rephrased to avoid it.

Full test suite passes (49/49 in the touched files, run 3x to confirm) except one pre-existing flaky test unrelated to this change (test_existing_client_language_falls_back_to_newest_file - a mtime-resolution race condition; confirmed it fails intermittently on a clean main checkout with none of these changes too, ~40% of runs in this environment). ruff check is clean on every file this touches (8 pre-existing lint errors elsewhere on main, none in the touched lines).

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Summary by cubic

Adds Java as a supported output language. Generates a minimal Maven project using java.net.http.HttpClient and Gson, runnable with mvn -q -f path/to/pom.xml compile exec:exec.

• New Features

  • Add output_language: "java" to settings and CLI.
  • New Java partial; generates api_client.java, README.md, and pom.xml with Gson and exec-maven-plugin configured to run via exec:exec.
  • Language mapping for .java and name "Java". Docs and tests updated.

• Bug Fixes

  • Make Maven runs work from any cwd by passing -f the run’s pom.xml (absolute and shlex.quote-escaped; resolves relative scripts_dir).
  • Compile root-level source by setting <sourceDirectory> to . in the POM.
  • Use exec:exec instead of exec:java to run the package-private ApiClient reliably across platforms.
  • Remove a {...} literal from the Java partial to avoid str.format_map KeyError.

^{Written for commit 1a641bb. Summary will update on new commits.}

Greptile Summary

This PR adds Java as a supported output language. The main changes are:

• Java client generation using JDK HttpClient and Gson.
• A minimal Maven project with root-level source compilation.
• Java language selection, file naming, and run-command support.
• Updated documentation and Java-specific tests.

Confidence Score: 5/5

This looks safe to merge.

• The Maven command now targets the generated POM from any working directory.
• Relative paths and shell-sensitive output paths are handled safely.
• The generated Maven project is instructed to compile the root-level Java source.
• No blocking issues were found in the updated code.

Important Files Changed

Filename	Overview
src/reverse_api/base_engineer.py	Adds Java metadata, Maven output files, and an absolute shell-quoted Maven command.
src/reverse_api/prompts/partials/_language_java.md	Adds Java generation instructions with Gson, HttpClient, and root-level Maven source compilation.
src/reverse_api/cli.py	Adds Java to the interactive output-language setting.
tests/test_base_engineer.py	Adds coverage for Java extensions, prompts, and Maven command path handling.
tests/test_prompts.py	Adds coverage for loading and formatting the Java prompt partial.

_{Reviews (2): Last reviewed commit: "Resolve scripts_dir to an absolute path ..." | Re-trigger Greptile}

[greptile-apps]

Java Runs Remain Python-Only

Selecting Java creates api_client.java, but the existing run workflow discovers only .py files and launches selected files with the virtualenv Python interpreter. A Java run is therefore omitted from run --ls, reports that no Python scripts exist, or produces a Python syntax error when passed explicitly.

Prompt To Fix With AI

This is a comment left during a code review.
Path: src/reverse_api/cli.py
Line: 1086

Comment:
**Java Runs Remain Python-Only**

Selecting Java creates `api_client.java`, but the existing `run` workflow discovers only `.py` files and launches selected files with the virtualenv Python interpreter. A Java run is therefore omitted from `run --ls`, reports that no Python scripts exist, or produces a Python syntax error when passed explicitly.

How can I resolve this? If you propose a fix, please make it concise.

[kind-agent]

⚠️ Error — The test run failed unexpectedly.

Snapshot kind-sandbox is inactive

This is likely a transient issue. You can re-trigger a run from the dashboard.

[cubic-dev-ai]

All reported issues were addressed across 10 files

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[kalil0321]

@greptile review