With Sharing & Without Sharing keywords in APEX

 

With Sharing Keyword:  When you want to enforce sharing rules that apply to the 

current user while executing an Apex class, you must use With Sharing keyword for the 

class. Without With Sharing keyword, the class would execute in system context, i.e. the 

sharing rules will not be applied for the current user. So the records that are not suppose to be 

accessed by the current user will be exposed.

The only exceptions to this rule are Apex code that is executed with the 

executeAnonymous call and Connect in Apex. executeAnonymous always executes 

using the full permissions of the current user.

Example:

    public with sharing class sharingClass {

// Code here

}

Without Sharing Keyword:  It ensures that the sharing rules of the current user are 

not enforced.  So why do we have to explicitly define Without Sharing as if you don't 

mention any keyword, it will enforce sharing rules as it will execute in system context? The 

answer is when the class(no sharing is mentioned ) is called from another class that is 

declared using With Sharing then sharing is enforced for the called class. To avoid such 

situation, we can explicitly define Without Sharing so that the class (no sharing is 

mentioned ) will run in system context.

Example:

    public without sharing class nosharing {

// Code here

}

Important things to Remember about Sharing Keywords:

•   The Sharing settings are applied on the class where the method is defined, not of the

  class where the method is called. For example, if a method is defined in a class with With

 Sharing and the method is called from a class declared with Without Sharing, the method

  executes with sharing rules enforced.

•   A class isn’t declared as either with or without sharing, the class doesn’t enforce sharing

rules for the current user except when it acquires sharing rules from another class. For 

example, if the class is called by another class that has with sharing keyword, then sharing is

 enforced for the called class. 

•    Both inner classes and outer classes can be declared as With Sharing. The sharing 

  setting applies to all code contained in the class, including initialization code, constructors,

  and methods but Inner classes do not inherit the sharing setting from their container class.

•  A class can inherit sharing setting from a parent class when one class extends or 

implements another.