APEX: Use a dynamic string to create an instance of a class

In Salesforce Apex, creating an instance of a class dynamically using a string involves leveraging the Type class. This approach is useful when the class name is determined at runtime. Here’s how you can achieve this:

Steps to Dynamically Create an Instance of a Class in Apex

Class Names in String Form:

You start with the class name in string form.

  String className = 'MyClass';

Using the Type Class:

Use the Type.forName method to get the Type reference for the class.

Type t = Type.forName(className);

Instantiate the Class:

Create an instance of the class using the newInstance method of the Type class.

Object obj = t.newInstance();

Casting to the Appropriate Type:

Cast the object to the specific class type if you need to call methods on it.

MyClass instance = (MyClass) obj;
instance.myMethod();

Complete Example

Here’s a complete example demonstrating these steps:

public class DynamicInstanceCreator {
    public void createInstance() {
        // The class name is provided as a string
        String className = 'MyClass';
        // Get the Type reference
        Type t = Type.forName(className);
        // Create an instance of the class
        Object obj = t.newInstance();
        // Cast the object to the appropriate class
        MyClass instance = (MyClass) obj;
        // Call a method on the instance
        instance.myMethod();
    }
}
public class MyClass {
    public void myMethod() {
        System.debug('Method executed!');
    }
}

Handling Exceptions

Check Existence of the Class:

Handle cases where the class might not exist.

try {
    Type t = Type.forName(className);
    Object obj = t.newInstance();
} catch (TypeException e) {
    System.debug('Class not found: ' + e.getMessage());
}