BugBench

Static analysis, auto-fix refactoring, and JUnit test scaffolding for Java and Kotlin, designed for VS Code and Kiro. Powered by a JVM language server, with an MCP server bundled alongside so Kiro's agent can call BugBench's tools directly during reasoning.

Features

In-editor analysis

• 90+ custom rules on top of PMD 7.5 and SpotBugs.
• Diagnostics in the gutter as you open or save Java/Kotlin files.
• Severity-aware mapping (Blocker / Critical / Major / Minor / Info) surfaced through VS Code's standard Problems panel.

Auto-fix refactoring

• Lightbulb code actions on every auto-fixable issue. ~22 fixers cover try-with-resources, empty catch blocks, unused imports, cognitive complexity, magic numbers, optional misuse, Spring lifecycle, REST controller hardening, Camel route bugs, and more.
• One-shot CodeRef-style workspace refactor: BugBench: Apply auto-fixes to current file.

Test scaffolding

• Code-lens above every Java class: ▸ Generate tests with BugBench.
• Produces JUnit 5 + Mockito scaffolds with Spring/Camel/REST awareness — recognises @Service, @RestController, RouteBuilder, Processor, etc., and tailors the generated test to each class type.
• Save-to-convention flow: writes the new test under the src/test/java mirror of the source's package or, if the file already exists, opens a side-by-side diff.

Workspace report

• BugBench: Scan workspace and open report walks the entire project, runs analysis on every source, and renders an interactive HTML report inside a VS Code/Kiro webview. Severity pills, per-file expandable issue tables, theme-aware colours.

Agent integration via MCP

• Bundles a Model Context Protocol server. On Kiro, BugBench auto-registers itself at user level and prompts once per workspace to register at workspace level (Kiro requires the workspace-level entry for the agent to see the tools).
• Tools the agent can invoke: getJavaContext, findSymbol, listIssues, listAvailableRefactors, applyRefactor, previewRefactor, generateTests. Mutating tools are dry-run by default — the agent must pass confirm=true for any file to change. Path arguments are validated against the workspace root.
• The same MCP server jar can be plugged into Cursor, Claude Desktop, or Claude Code via the BugBench: Install MCP server for current host (copy JSON snippet) command.

Requirements

• JDK 17 or newer on PATH or in JAVA_HOME (or set bugbench.javaHome in settings). The extension refuses to run on older JDKs and surfaces a notification with a one-click "Download JDK 21" action.
• VS Code 1.85+ or any Kiro version that ships at or above that engine.
• Real filesystem (refactor and test-gen require it). Virtual / remote workspaces have limited support.

Quick start

1. Install the extension from the Marketplace (or from a .vsix via Extensions: Install from VSIX...).
2. Open a Java/Kotlin project.
3. Wait ~3 s for diagnostics to appear in the gutter and the Problems panel.
4. (Kiro only) When prompted, click Register here on the workspace-level MCP registration banner, then fully restart Kiro. Verify by asking the agent: "Use getJavaContext on this workspace."