Salesforce Interview Question and Answers on Apex Class

1. Difference between with sharing and without sharing in salesforce

Ans. By default, all Apex executes under the System user, ignoring all CRUD, field-level, and row-level security (that is always executes using the full permissions of the current user).

with sharing:

Enforcing the User’s Permissions, Sharing rules and field-level security should apply to the current user.

For example:

public with sharing class sharingClass {

         // Code here

}

without sharing:

Not enforced the User’s Permissions, Sharing rules and field-level security.

For example:

public without sharing class noSharing {

        // Code here

}

2. Access Modifiers  in salesforce 

Ans.

– private: This method/variable is accessible within the class it is defined.

– protected: This method/variable is also available to any inner classes or sub-classes. It can only be used by instance methods and member variables.

– public: This method/variable can be used by any Apex in this application namespace.

– global: this method/variable is accessible by all Apex everywhere.

• All methods/variable with the web-service keyword must be global.

– The default access modifier for methods and variables is private.

3. Exceptions Statements  in salesforce 

Ans.

Throw: signals that an error has occurred and provides an exception object.

• Try: identifies the block of code where the exception can occur.

• Catch: identifies the block of code that can handle a particular exception. There may be multiple catch blocks for each try block.

• Finally: optionally identifies a block of code that is guaranteed to execute after a try block.

Exception Example:

public class OtherException extends BaseException {}

Try{

     //Add code here

     throw new OtherException(‘Something went wrong here…’);

} Catch (OtherException oex) {

     //Caught a custom exception type here

} Catch (Exception ex){

     //Caught all other exceptions here

}

4. What is the difference between a standard controller and custom controller ?

     Ans: standard controller inherits all the standard object properties, standard button functionalities can be directly used. Custom controller defines custom functionalities, a standard controller can be extended to develop custom functionalities using keyword "extensions"

5. How to get current logged in users id in apex ?

Ans. Userinfo.getuserid()

6. How to fire dynamic query in SOQL?

Ans. Database.query('select name from account'); 

7. How can you lock records in apex?

Ans. Use For update in query to lock the record. For example: [select id,name from contact limit 10 For update];

8. How can you access custom label in apex ?

Ans. System.Label.LabelNamehere

9. What is search layout? 

Ans . When we click on lookup field the results which is shown is called search layout.

10. What is mini page layout ? 

Ans. For lookup fields on record detail page we see a link, whenever we put cursor on that link we see a popup window which displays few fields.