What is a Future Method in Salesforce?

A Future Method is a way to run processes in the background in Salesforce. This helps to avoid delays for users by running long tasks asynchronously.

Why do we use Future Methods in Salesforce?

We use Future Methods to run operations that take a long time in the background, like callouts to external services or processing large amounts of data. This keeps the app fast and responsive for users.

How do you declare a Future Method in Apex?

You declare a Future Method using the @future annotation. Here's an example:

Can Future Methods return a value? Explain.

No, Future Methods cannot return a value. They must always have a void return type because they run asynchronously.

What is the syntax to call a Future Method?

To call a Future Method, you simply call it like a regular static method. Example:

Give an example of a situation where you would use a Future Method.

One example is making a callout to an external web service. Since callouts can take time, using a Future Method ensures the user doesn’t have to wait.

How do Future Methods help with governor limits?

Future Methods run asynchronously, which means they help avoid hitting limits by processing data in smaller chunks and by running operations that can exceed synchronous limits.

Can you make a callout to an external service from a Future Method? Why or why not?

Yes, you can make callouts from a Future Method because it runs asynchronously, which is allowed for callouts.

What are the limitations of using Future Methods in Salesforce?

Limitations include: 1. Cannot return values. 2. Cannot be called from a trigger before insert or before update. 3. Limited to 250,000 asynchronous requests per 24-hour period.

Can you use a Future Method inside a trigger? Explain.

You can use a Future Method in a trigger, but not in a before trigger. It should be used in after triggers because the records need to be committed to the database.

What are the differences between Future Methods and Queueable Apex?

Future Methods are simpler but less powerful. Queueable Apex allows for job chaining, complex data structures, and better error handling.

How do you test a Future Method in Salesforce?

To test a Future Method, use Test.startTest() and Test.stopTest() to ensure the Future Method runs within the test context.

What happens if a Future Method fails?

If a Future Method fails, the error is logged, and the method does not retry automatically. You should add error handling to manage failures.

Can you chain multiple Future Methods together? Why or why not?

No, you cannot chain Future Methods because they do not guarantee the order of execution and can lead to complex, hard-to-maintain code.

Explain the @future annotation. What does it do?

The @future annotation tells Salesforce to run the method asynchronously in the background.

How do you pass parameters to a Future Method?

You pass parameters to a Future Method just like any other method. However, parameters must be primitive types, collections of primitive types, or collections of sObjects.

What are the best practices for writing Future Methods?

Best practices include: 1. Keeping the method simple. 2. Using try-catch blocks for error handling. 3. Avoiding DML operations if possible. 4. Not using in before triggers.

Can you use Future Methods with Visualforce controllers? Explain.

No, you cannot call a Future Method directly from a Visualforce controller constructor, getter, or setter. It should be called from an action method.

How would you debug issues with Future Methods?

To debug issues, use system logs, debug logs, and error handling within the Future Method to capture and log exceptions.

What are the governor's limits specifically for Future Methods?

Governor limits for Future Methods include: 1. Up to 50 Future Method invocations per transaction. 2. Each Future Method counts towards the 250,000 asynchronous requests per 24-hour period.

Explain a scenario where using a Future Method improved performance.

When making bulk API callouts to update external systems, using Future Methods allowed the callouts to run asynchronously, improving the app's performance by not blocking the user interface.

Can a Future Method be called from a batch class? Why or why not?

Yes, a Future Method can be called from a batch class. This is useful for performing tasks that require asynchronous processing, such as callouts.

How do Future Methods handle large data volumes?

Future Methods handle large data volumes by running asynchronously, allowing for smaller chunks of data to be processed in each call, thus helping to avoid hitting governor limits.

Why can't Future Methods be used before triggers?

Future Methods cannot be used in before triggers because the records have not been committed to the database yet, and asynchronous processing requires committed data.

What should you consider when using Future Methods with complex calculations?

When using Future Methods with complex calculations, consider breaking down the calculations into smaller tasks, handle exceptions properly, and ensure that the tasks do not exceed governor limits. These answers, along with code snippets and explanations, should help in understanding the practical aspects of Future Methods in Salesforce.

What is the impact of using a Future Method on transaction control and visibility?

Future Methods run in a separate transaction from the calling code. This means they do not have access to the original transaction's state and do not share locks or commit points with the original transaction.

How do you handle exceptions in a Future Method to ensure robust error handling?

Use try-catch blocks within the Future Method to handle exceptions. You can also use custom logging mechanisms or platform events to capture and report errors.

Can you use @future methods to process data from a CSV file uploaded by a user? Explain how.

Yes, you can use @future methods to process data from a CSV file. First, store the uploaded file as an attachment or document, then parse the file data within the Future Method.

What are the security implications of using Future Methods, and how can you mitigate them?

Future Methods run with the permissions of the user who invoked them. Ensure that the method adheres to the principle of least privilege, and validate input data to prevent injection attacks.

How would you implement a retry mechanism for a Future Method that occasionally fails due to external system issues?

Implement a retry mechanism by checking the error type and counting retry attempts. You can re-invoke the Future Method or use a combination of Future Methods and Queueable Apex for more control over retries.

How do Future Methods interact with the Salesforce governor limit for callouts?

Future Methods are subject to governor limits for callouts, which include a limit of 100 callouts per transaction. Ensure your Future Methods handle callout limits by managing batch sizes appropriately.

Can you call a Future Method from another Future Method? What are the implications?

No, you cannot call a Future Method from another Future Method. This limitation prevents the creation of complex, interdependent asynchronous operations that could be difficult to manage.

How would you handle large-scale data migration using Future Methods in Salesforce?

For large-scale data migration, break the data into smaller chunks and process each chunk asynchronously using Future Methods. Monitor progress and handle errors to ensure data integrity.

Explain how you can schedule a Future Method to run at a specific time.

Future Methods cannot be directly scheduled. Instead, use a combination of scheduled Apex and Future Methods. Schedule an Apex class to run at the desired time, and within that class, invoke the Future Method.

How would you optimize a Future Method to ensure it runs efficiently and within governor limits?

Optimize a Future Method by minimizing DML operations and SOQL queries within the method. Use collections to handle bulk operations and avoid nested loops. Ensure that the method processes only the necessary data.

Future Method Interview Questions: Real-World Scenarios

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