Apex is a proprietary programming language developed by Salesforce, which is specifically designed for developing applications on the Salesforce platform. It is a strongly-typed, object-oriented language with syntax that is similar to Java. In this beginner's guide, we will take a closer look at the history of Apex, learn its syntax and how to write it with an example, and explore its best applications.

History:

Apex was first introduced in 2007 as a part of the Salesforce platform. It was designed to provide a way for developers to extend the functionality of Salesforce applications beyond the limits of the built-in capabilities. Apex is based on the Java programming language, but it is designed to be more specialized and to work more closely with the Salesforce platform.

Syntax:

Apex syntax is similar to that of Java, with some key differences. Here are a few basic syntax elements:

1. Comments: Apex supports both single-line and multi-line comments. Single-line comments start with double forward slashes (//), and multi-line comments start with /* and end with */.

2. Variables: Variables in Apex must be declared with a specific data type, such as Integer, String, or Boolean. Variables can be assigned values using the equals sign (=).

3. Classes: Apex is an object-oriented language, so it uses classes to define objects. Classes in Apex are defined using the "class" keyword, followed by the name of the class.

4. Methods: Methods in Apex are similar to functions in other programming languages. They are defined within classes and can take arguments and return values.

Example:

Here is a simple example of Apex code that calculates the area of a rectangle:

```java
public class Rectangle {
  Integer length;
  Integer width;

  public Integer calculateArea() {
    return length * width;
  }
}

Rectangle r = new Rectangle();
r.length = 5;
r.width = 10;

Integer area = r.calculateArea();
```

In this example, we define a Rectangle class with two integer variables, length and width. We then define a method called "calculateArea" that calculates the area of the rectangle by multiplying the length and width. Finally, we create a new instance of the Rectangle class, set its length and width values, and call the "calculateArea" method to get the area of the rectangle.

Applications:

Apex is specifically designed for developing applications on the Salesforce platform, so its applications are quite focused. Some common use cases for Apex include:

1. Customizing Salesforce applications: Apex allows developers to create custom business logic, automate processes, and extend the functionality of Salesforce applications.

2. Integrating with external systems: Apex can be used to integrate Salesforce applications with other systems, such as databases, web services, and other applications.

3. Building custom applications: Apex can be used to build custom applications that run on the Salesforce platform, such as customer portals, partner portals, and custom mobile applications.

Conclusion:

Apex is a powerful programming language that is designed for developing applications on the Salesforce platform. With its strong object-oriented syntax, developers can create custom business logic, automate processes, and extend the functionality of Salesforce applications. As a beginner's guide, this document has provided a brief overview of the history of Apex, its syntax, an example of how to write Apex code, and its best applications. With further study and practice, developers can gain expertise in Apex and become proficient in developing Salesforce applications.