Salesforce Apex: Best Practices

Here are some best practices to write an Apex code:

1. Use bulkification: Bulkification is the process of designing code to efficiently process multiple records at once. This helps to reduce the number of database operations required and improves performance.
2. Avoid hardcoding IDs: Hardcoding IDs in Apex code can make it difficult to maintain and modify. Instead, use custom settings, custom metadata, or queries to retrieve the IDs.
3. Use proper naming conventions: Use clear and descriptive names for classes, methods, and variables. This makes your code easier to read and understand.
4. Use try-catch blocks for error handling: Use try-catch blocks to handle exceptions and errors in your code. This helps to prevent crashes and provides a more user-friendly experience.
5. Use meaningful comments: Use comments to explain the purpose and functionality of your code. This makes it easier for other developers to understand and modify your code.
6. Use SOQL for database operations: Use SOQL (Salesforce Object Query Language) instead of SQL for database operations. This ensures that your code is optimized for Salesforce's architecture.
7. Limit the use of triggers: Avoid using triggers for complex logic and instead use Apex classes. Triggers should be used only for simple operations like record validation.
8. Follow the principle of separation of concerns: Separate your code into different classes and methods to make it more modular and maintainable.
9. Use test classes: Write test classes to ensure that your code is functioning correctly and to prevent regressions.
10. Use design patterns: Use design patterns to solve common problems and to make your code more maintainable and scalable.
11. Minimize the use of DML statements: DML (Data Manipulation Language) statements are resource-intensive and can slow down your code. Try to minimize the use of DML statements and batch them where possible.
12. Avoid using nested queries: Avoid using nested queries in SOQL as they can result in performance issues. Instead, use joins or relationship fields to retrieve related records.
13. Use static methods where appropriate: Use static methods for methods that don't depend on instance variables. Static methods are faster and more efficient than instance methods.
14. Avoid using global access modifiers: Avoid using the global access modifier unless it's absolutely necessary. Global classes and methods are more difficult to maintain and can lead to security issues.
15. Use interfaces for abstraction: Use interfaces to define common behavior and abstract away implementation details. This helps to make your code more modular and maintainable.
16. Limit the use of nested loops: Avoid using nested loops as they can lead to performance issues. Instead, use maps or sets to optimize your code.
17. Use collections instead of arrays: Use collections like lists and sets instead of arrays. Collections are more flexible and easier to work with than arrays.
18. Use the @TestSetup annotation: Use the @TestSetup annotation to set up test data for your test methods. This helps to improve the performance of your test methods.
19. Use guard clauses for parameter validation: Use guard clauses to validate method parameters at the beginning of your methods. This helps to prevent errors and improve the readability of your code.
20. Write code for readability: Write your code in a way that is easy to read and understand. Use whitespace, indentation, and clear naming conventions to make your code more readable.

These are just a few best practices for writing a smart Apex code. Following these practices can help you to write cleaner, more efficient, and more maintainable code.