Optional .cursorrules Cursor AI Prompt File Examples

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Java Programming Guide .cursorrules prompt file

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Universal Java Cursor Rules Document

1. Introduction

This document provides guidelines and best practices for Java programming, focusing on core principles and modern practices relevant to Java source code manipulation and understanding. It is designed to assist students and developers in creating clean, efficient, and maintainable Java applications.

2. Java Naming Conventions

Class and Interface Names: Use CamelCase and start with uppercase letters. Examples: DataProcessor, Runnable.
Method Names: Use mixed case starting with a lowercase letter, reflecting the action performed. Example: calculateTotal.
Variable Names: Use descriptive names in mixed case starting with a lowercase letter. Avoid single-character names except for temporary looping variables.
Constants: Use all uppercase with underscores between words. Example: MAX_HEIGHT.
Enums: Treat enum names like class names (CamelCase) and constants in enums as uppercase. Example: enum Color { RED, GREEN, BLUE }.
Type Parameters: Use single uppercase letters. Common conventions include E for element and T for type.

3. Java Documentation Practices

JavaDoc: Properly document all public classes and methods using JavaDoc, focusing on the "why" and "how" of the code.
Inline Comments: Use inline comments sparingly to explain "why" something is done, not "how" it is done.

4. Code Structure and Organization

Modularity: Organize code into packages that reflect functionality and can be reused across different parts of the application.
Error Handling: Use exceptions to handle errors. Create custom exception classes when necessary to clarify the type of error.
Use of Generics: Utilize generics to create flexible and type-safe code, reducing runtime errors.

5. Java Core Libraries Utilization

Collections: Use Java Collections Framework effectively. Prefer ArrayList over arrays for resizable arrays, and use HashMap for key-value pairs.
Streams: Utilize the Stream API for processing collections of data in a declarative way.
Concurrency: Use Java Concurrency utilities like ExecutorService and ConcurrentHashMap to manage threads safely and efficiently.

6. Modern Java Features

Lambda Expressions and Functional Interfaces: Use lambda expressions to create concise and flexible code, particularly with collections and threading.
Optional Class: Use Optional to represent nullable value without using null, which can help prevent NullPointerException.
Java Modules: Use the Java Platform Module System (JPMS) for better encapsulation and dependencies management.

7. Performance Optimization

Avoid Premature Optimization: Focus on writing clear and simple code before optimizing. Use profiling tools to identify bottlenecks.
Memory Management: Understand object creation costs and manage resources using try-with-resources to automatically close resources.

8. Testing and Debugging

Unit Testing: Write unit tests using frameworks like JUnit to ensure each part of the application works as expected independently.
Debugging: Use debugging tools within IDEs to step through code and understand the flow and state of the application.

9. Adherence to Java Language and JVM Specifications

Compliance: Ensure code complies with the Java Language Specification and JVM specifications to avoid platform-specific issues and ensure portability.

10. Ethical and Professional Practices

Code of Conduct: Adhere to ethical coding practices, respecting copyright and licensing of third-party libraries.
Continuous Learning: Stay updated with the latest Java developments and participate in forums and communities to enhance skills.

Universal Java Cursor Rules Document - Updated Section

11. File Naming Conventions

When creating new files within a Java project, it is important to adhere to consistent naming conventions to ensure that files are easily identifiable and accessible. This section outlines the recommended practices for naming files in Java projects.

CamelCase Naming: Use CamelCase for naming Java class files. This is consistent with the naming of the classes themselves and helps maintain readability. Example: UserProfile.java, FileProcessor.java.
Dashes for Non-Class Files: For non-class files, such as scripts, configurations, or logs, use dashes to separate words. This improves readability in systems where CamelCase is not typically used. Example: config-file.properties, error-log.txt.
Consistency Across the Project: Ensure that all team members follow the same naming conventions to avoid confusion and maintain consistency across the project's codebase.
Avoid Special Characters: Except for the dash (-) in non-class files and the underscore (_) in specific cases like test files, avoid using special characters in file names. This prevents issues related to different operating systems' file handling.
Descriptive Names: File names should be descriptive and give a clear indication of their purpose or contents without needing to open them. Avoid vague names like util.java or helper.txt, which do not provide insight into the file's functionality.

By following these file naming conventions, developers can ensure that their Java projects are organized and that their files are easily manageable and accessible. This practice is crucial for collaborative environments and contributes to the overall maintainability of the codebase.

This document aims to guide students in mastering Java programming by adhering to established conventions and modern practices, ensuring they develop robust, maintainable, and efficient Java applications.

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Java Programming Guide .cursorrules prompt file

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Java Lambda Streams Security .cursorrules prompt file

Java-Specific Rules for AI
General Coding Practices & Style
Naming Conventions:
"Use camelCase for variable and method names."
"Use PascalCase for class and interface names."
"Use all uppercase letters and underscores for constants (e.g., MAX_VALUE)."
Code Organization:
"Keep classes and methods small and focused on a single responsibility."
"Use meaningful package names to organize your code."
"Place imports at the top of the file, grouped and sorted."
Error Handling & Logging:
"Use exceptions to handle exceptional situations, not for flow control."
"Provide informative exception messages."
"Use logging frameworks (e.g., Log4j, SLF4J) for debugging and auditing."
Java 8+ Features:
"Leverage lambda expressions and streams to write concise and expressive code."
"Prefer using the Optional class over null checks."
"Use the @FunctionalInterface annotation for functional interfaces.
Code Review Specific
"Pay attention to potential performance bottlenecks (e.g., unnecessary object creation, inefficient algorithms)."
"Check for proper use of Java collections and data structures."
"Review for thread safety issues in multithreaded code."
"Look for opportunities to apply design patterns to improve code structure."
AI Assistant's Behavior
"When providing code examples, include java doc comments as well as inline comments explaining the logic. When explaining loops, console log the step of each element of the loop to demonstrate the loops use and iterative construction of the desired outcome"
"If the request is unclear or ambiguous, seek clarification before generating code."
"Adhere to the latest Java language features and best practices."
"Favor composition over inheritance when designing class hierarchies."
"Avoid excessive use of static methods and variables."
"Use the final keyword for variables that should not be reassigned."
"Always override the hashCode and equals methods when necessary."
"Use Java annotations effectively to provide metadata and improve code readability."
"Use Java generics judiciously to write reusable and type-safe code."
"Save Java generics are new files with descriptive names and java doc comments describing thier application."
"Utilize Java concurrency utilities (e.g., ExecutorService, CountDownLatch) for efficient multithreaded programming."
"Employ Java reflection judiciously for dynamic code execution."
General Coding Practices & Style
Clarity & Maintainability
"Prioritize code readability over clever tricks."
"Decompose complex methods into smaller, more manageable ones."
"Use descriptive variable names that convey their purpose."
"Maintain consistent indentation and spacing."
Performance & Efficiency
"Avoid premature optimization, but be mindful of potential performance bottlenecks."
"Use lazy initialization for expensive resources."
"Prefer primitive types over wrapper classes when possible."
"Minimize object creation within loops."
Testing & Documentation
"Write unit tests to verify correctness and prevent regressions."
"Document public APIs using Javadoc comments."
"Include comments to explain non-obvious code sections or algorithms."
Security & Robustness
"Validate input to prevent vulnerabilities like SQL injection and cross-site scripting."
"Handle potential exceptions gracefully."
"Avoid hardcoding sensitive information."
"Use secure coding practices to prevent common vulnerabilities."
Code Review Specific
"Provide clear and actionable feedback with specific examples."
"Suggest alternative approaches when applicable."
"Balance technical correctness with practical considerations."
"Foster a collaborative and respectful code review culture."
AI Assistant's Behavior
"When suggesting code improvements, consider the project's context and constraints."
"Provide explanations and justifications for proposed changes."
"Offer alternative solutions when multiple approaches exist."
"Be open to feedback and willing to revise suggestions."
Example
"Favor immutability to reduce side effects and improve thread safety."
"Use the diamond operator (<>) for generic type inference."
"Avoid excessive nesting of if statements and loops."
"Leverage Java's built-in libraries and tools whenever possible."
"Keep up-to-date with the latest Java language features and best practices."
Advanced
"Consider using a dependency injection framework for improved modularity and testability."
"Explore reactive programming paradigms using libraries like RxJava or Project Reactor."
"Utilize Java profiling tools to identify performance hotspots."
"Apply domain-driven design principles to structure complex applications."
"Always uses this type of optional check when dealing with potentially null arrays"
Request for AI:

When writing Java code that involves potentially null arrays, always use the following pattern to check for null and empty arrays using [Optional]

public Optional`<String>` longestCommonPrefix(String[] strs) {    Optional`<String[]>` optStrs = Optional.ofNullable(strs);    if (!optStrs.isPresent() || optStrs.get().length == 0) {        return Optional.empty();    }    // Continue with the logic}

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