2 GP Salesforce

 Unlocked packages are best to build your application in modular way

With 2nd GP, Salesforce defines the modular application development.

Note :

Our end goal here is to create a version able, maintainable, installable and upgradable package.

Before we start creating unlocked package, we need to do following -

1.      Enable Dev hub in org.

2.      Enable 2nd generation managed packaging.

3.      Install CLI

Five Key Features of 2GP

1.100% source - driven Package Development.

2.Declarative package Configuration.

3.Flexible version management.

4.Multiple Packages in a single namespace.

5.Package Bundles.

Enhanced Support for @namespaceAccessible Annotation :

The @namespaceAccessible annotation provides enhanced support for accessing interfaces, properties, and abstract classes in second-generation packages.

Features: The @namespaceAccessible annotation improvements include:

The @namespaceAccessible annotation now supports interfaces, properties, and abstract classes

A public or protected variable or method with the @namespaceAccessible annotation must be in a class that is declared as public 

and annotated with @namespaceAccessible

A public or protected inner class with @namespaceAccessible annotation must be enclosed in an outer class that is declared as 

public and annotated with @namespaceAccessible

Note :

The @namespaceAccessible makes public Apex in a package available to other packages that use the same namespace. 

Without this annotation, Apex classes, methods, interfaces, and properties defined in a 2GP package aren’t accessible to the other packages 

with which they share a namespace. Apex that is declared global is always available across all namespaces, and needs no annotation.

You need to explicitly grant access per member.

ex: 

@namespaceAccessible

public with sharing class AuraResult {

    

    @namespaceAccessible    

    public Boolean success = false;

    @namespaceAccessible

    public String message = ''; 

    @namespaceAccessible

    public AuraResult() {

    }

    @namespaceAccessible

    public Boolean getSuccess() {

        return success;

    }

    @namespaceAccessible

    public void setSuccess(Boolean success) {

        this.success = success;

    }

    @namespaceAccessible

    public String getMessage() {

        return message;

    }

    @namespaceAccessible

    public void setMessage(String message) {

        this.message = message;

    }

}

Package Bundles :

1.Allow single-click installation of bundled packages that share a namespace.

2.Be clearly identifiable as a bundle in Setup UI in the subscriber Org.

3.Be flexible enough to allow for entire or partial-bundle push upgrades.