Apex Interview Questions

 The abstract classes in Salesforce Apex are the classes that involve at least one dynamic strategy. A conjectural method is an approach that is checked however it contains no use at all.

 Here are a couple of considerations required for the Static keyword in Apex.

•   You cannot make an Apex class static.
•   Static is just allowed in the outer class.
•   The Static variables are not mainly exchanged like a View State part.
•   Static block and static variables keep running inside and out in which they are made in a class.
•   Static variables are static just to the demand’s extent.

1. fabricates proficient looking web applications that are both quick and secure.
2. Keeps running on and lives in the Oracle database. The Apex framework and metadata are put away in Oracle tables.
3. It is FREE. No authorizing required.
4. Quick expectation to learn and adapt for designers to build the application.
5. The application deployment is as basic as ‘Export and Import’ if hardcoded references of values that change between situations are kept away from.
6. Parcel of extension for customization of use look and feel.
7. Adaptable for high client volume. ASKTOM, previous ORACLE METALINK (before moved to Flash adaptation) and MANY APPLICATIONS are mainly built utilizing APEX.
8. Can usually be configured to utilize Oracle SSO and EBS fnd client repository.

1. Upsert triggers fire both before and after the insert or when update triggers as proper.
2. Merge triggers fires both
3. Field history isn’t recorded until the trigger end. If you question field history in a trigger, you won’t perceive any history for the present transaction.
4. You can just utilize the webService keyword in the trigger when it is in a technique characterized as offbeat; that is, the point at which the strategy is described with the @future keyword.
5. A trigger conjured by an insert, update or delete of the recurring event or repeating task brings about a runtime error when the trigger is brought in bulk from the Force.com API.
6. Merge trigger doesn’t fire their own trigger rather they fire update or delete of losing and winning records individually.

 Since APEX is so firmly incorporated into the database, you would prototype screens while sitting with the client. The Object Browser enables you to make database questions, for example, tables notwithstanding seeing those same articles. This allows you to make protests on the fly and after that construct tables around those articles.

The IDE, including the above Table developer, and all applications are kept running inside a browser. Turn around time is quick. Since APEX is revelatory, you can without much of a stretch roll out improvements progressively by means of the implicit wizards.

Since APEX controls session data for you, and because you utilize the security structure incorporated with the Oracle Database, you would concentration be able to deliver applications, not on association setup and another typical advancement time wasters.

 ActionPoller is a clock in Apex that empowers an AJAX refresh demand to be sent to the server as is told by a period between the time that the software developer decides.

•   Each savepoint you set against governor limit for DML proclamations.
•   Static variables are not returned amid a rollback. If you attempt to run the trigger once more, the static variables hold the qualities from the main run.
•   Each rollback represents a mark against governor limit for DML articulations. You will get a Runtime mistake if you attempt to rollback the extraordinary database circumstances.
•   The ID on a sObject embedded subsequent to setting a savepoint isn’t cleared after a rollback.

 The Beta version APEX 4.2 is available in the market a few weeks back. This new form offers numerous upgrades. Among the most helpful are:

• Print to PDF Users can send out their reports and screens to PDF yield.
• Migrate from MS-AccessUsing the export tool and the Access Migration Workbench, you can relocate client applications to APEX.
• Calendar Widget Older forms incorporated a date-book gadget yet now clients can pick between day, week, or month date-books.
• Improved Page and Region Caches Caching enhances execution.
• Application Builder Defaults The engineer can set defaults for wizards to diminish improvement time (fundamental themes for development). The advantages of updating incorporate execution upgrades and extra usability features for both the designer and the end client.

Oracle Database 10g Express Edition just backings Oracle APEX version 2.2.

 ALL ROWS keywords can be utilized to get every one of the records incorporating records in recycle bin.

 If you wish to recover or refer a required ID in the Visualforce page at that point, you can simply refer to it using a standard controller.

Trigger.new:

•  This command is used to return the list of new forms of object records
•  It is important to keep in mind that the sObject list is only accessible in the update and delete triggers
•  i.e., Trigger.new is accessible before and after inserts, before and after the update.
•  In Trigger.new the records must be changed in before triggers.

Trigger.old:

•  This command is used to return the list of old variants of the sObject records.
•  It is important to keep in mind that the sObject list is only available in delete and update triggers.
•  Trigger.old is accessible in after inserting, after the update, before deleting and after updating.

 The Public access modifier is not quite the same as people in general modifier in Java. The public class can be accessed inside an application or namespace. While the Global class is mainly noticeable wherever: in any of the application or the namespace. The Webservice must be proclaimed as Global so it can be accessed outside of the application. The global variable is like open modifier in Java.

It is the essential feature which is utilized just to invoke the Apex classes to enable them to keep running at unequivocal circumstances, to start with, execute the Schedulable assemblage for the class, at that point express the calendar by using either the Schedule Apex page or the System.

 In a domain where you are leading protest situated sort of programming, a virtual class is a term alluded to a settled kind of internal class whose limit alongside the part factors can be effortlessly abrogated and furthermore renamed by alternate subclasses of some other outer class. Virtual classes are something that intently looks like the virtual limits of the program.

 It is mainly a connection with URL. This part is rendered in HTML as anchor tag with a href property. The body of the OutputLink is content or picture that shows the connection. 

 An interface takes after a class in which none of the strategies have been executed—the system marks are there, yet the body of each methodology is void. To use an interface, another class must realize it by giving a body to most of the procedures contained in the interface.

Interfaces can give a layer of reflection to your code. They isolate specific execution of a system from the declaration for that procedure. In this manner, you can have unmistakable use of a methodology in perspective of your particular application.

 An interface is a group of unimplemented strategies. This will indicate the signature of the strategy, kinds of inputs that we pass the technique determine what compose is given as a yield.

NOTE: Generally the interface techniques we give it as a global.

 Apex is mainly in-house technology that is just like Java programming with object-oriented ideas and to compose our own particular custom logic.

1. Apex is the procedural scripting language in the discrete and executed by the Force.com stage.
2. It runs locally on the Salesforce servers, making it more ground-breaking and quicker than non-server code, for example, JavaScript/AJAX.
3. It utilizes the syntax that resembles Java
4. Apex can be written in triggers that demonstration like database put away techniques.
5. Apex enables designers to join business logic to the record spare process.
6. It has worked in help for unit test creation and execution.

 It is a class which is usually modified for running the pre-defined interim.The class must actualize schedulable interface and it contains technique named execute().Yes, we can call apex techniques utilizing javascript. We can accomplish this by using the ActionFunction.

apex:PageMessages: This part shows all messages that were produced for all the components on the present page, introduced utilizing the salesforce styling. This will display both salesforce produced messages and also custom messages added to the ApexPages class.

apex:PageMessage: Apex: PageMessage is a segment that includes single message the page. This is utilized to show custom message utilizing the salesforce formatting.

apex:Message: apex: Message is utilized to show a mistake on just a particular field. It is utilized to enable developers to put handle particular mistakes in the particular area.

apex:Messages: apex: Messages is like apex: Message yet it shows all the errors.