Cursor-rules-java 124-java-secure-coding

Use when you need to apply Java secure coding best practices — including validating untrusted inputs, defending against injection attacks with parameterized queries, minimizing attack surface via least privilege, applying strong cryptographic algorithms, handling exceptions securely without exposing sensitive data, managing secrets at runtime, avoiding unsafe deserialization, and encoding output to prevent XSS. Part of the skills-for-java project

install

source · Clone the upstream repo

git clone https://github.com/jabrena/cursor-rules-java

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/jabrena/cursor-rules-java "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/124-java-secure-coding" ~/.claude/skills/jabrena-cursor-rules-java-124-java-secure-coding && rm -rf "$T"

manifest: skills/124-java-secure-coding/SKILL.md

Java Secure coding guidelines

Identify and apply Java secure coding practices to reduce vulnerabilities, protect sensitive data, and harden application behaviour against common attack vectors.

What is covered in this Skill?

Input validation: type, length, format, and range checks
SQL/OS/LDAP injection defence via
```
PreparedStatement
```
and parameterized APIs
Attack surface minimisation: least-privilege permissions, removal of unused features
Strong cryptography: BCrypt/Argon2 for passwords, AES-GCM for encryption, digital signatures; avoid deprecated ciphers (MD5, SHA-1, DES)
Secure exception handling: log diagnostic details internally, expose only generic messages to clients
Secrets management: load credentials from environment variables or secret managers — never hardcoded
Safe deserialization: strict allow-lists, prefer explicit DTOs over native Java serialization
Output encoding to prevent XSS in rendered content

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 secure coding 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 secure coding pattern

When to use this skill

Review Java code for secure coding

Reference

For detailed guidance, examples, and constraints, see references/124-java-secure-coding.md.