123-java-exception-handling

A set of guidelines for handling errors in Java programs. It covers choosing suitable error types, cleaning up resources, preserving useful context, validating inputs, and recording failures safely.

In plain words
What is it for?
Reviewing or writing Java code that detects invalid input, manages resources, logs failures, retries safe operations, translates errors at API boundaries, or handles interrupted and asynchronous work.
Why use it?
It helps prevent errors that are vague, leak sensitive information, hide the original cause, or leave files and other resources open. It also addresses retries, timeouts, interruption, and asynchronous failures.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/jabrena/cursor-rules-examples/123-java-exception-handling
Any agent
npx skills add jabrena/cursor-rules-examples --skill 123-java-exception-handling
Clone the repo
git clone --depth 1 https://github.com/jabrena/cursor-rules-examples

Made for: Claude Code, Codex.

Per session 105 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 592 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00105 $0.00592
Opus 5 $0.00053 $0.00296
Sonnet 5 $0.00021 $0.00118
Haiku 4.5 $0.00011 $0.00059

Measured 2d ago against content hash f892a8b67316, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

123-java-exception-handling scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agents/skills/123-java-exception-handling/SKILL.md · 52 lines

How it starts

The opening of the file, as written. The whole thing — 52 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Java Exception Handling Guidelines

Identify and apply robust Java exception handling practices to improve error clarity, security, debuggability, and system reliability.

What is covered in this Skill?

  • Specific exception types instead of generic Exception/RuntimeException
  • try-with-resources for automatic resource cleanup
  • Secure exception messages that avoid information leakage
  • Exception chaining to preserve full error context
  • Early input validation with IllegalArgumentException/NullPointerException
  • InterruptedException handling with interrupted-status restoration
  • @throws JavaDoc documentation, fail-fast principle
  • Structured logging with correlation IDs, avoiding log-and-throw duplication
  • API boundary translation via centralized exception mappers
  • Bounded retry with backoff for idempotent operations only
  • Timeout enforcement with deadline propagation
  • Throwable#addSuppressed for secondary cleanup failures
  • Never catching Throwable/Error
  • Observability via error metrics
  • Failure propagation in async CompletionStage code

Scope: The reference is organized by examples (good/bad code patterns) for each core area. Apply recommendations based on applicable examples.

Constraints

Before applying any exception handling changes, ensure the project compiles. If compilation fails, stop immediately — do not proceed until resolved. After applying improvements, run full verification.

  • MANDATORY: Run ./mvnw compile or mvn compile before applying any changes
  • SAFETY: If compilation fails, stop immediately — do not proceed until the project is in a valid state
  • VERIFY: Run ./mvnw clean verify or mvn clean verify after applying improvements
  • BEFORE APPLYING: Read the reference for detailed good/bad examples, constraints, and safeguards for each exception handling pattern

When to use this skill

  • Exception handling
  • Use try-with-resources in Java code
  • Create exception chaining in Java code
  • Apply fail-fast validation in Java code

Read the full file on GitHub · 52 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 52 lines · 105 tokens per session scan A f892a8b67316

Subscribe to this mod's changes

123-java-exception-handling is a skill published in the GitHub repository jabrena/cursor-rules-examples (2 stars, last pushed 6d ago), licensed Apache-2.0. It adds 105 tokens to every session and 592 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.