Explain the mechanism of how the method for setting an object's property value works.

In Java, a method that sets the value of an object's property is usually called a setter. It is a method that allows setting the value of a private class field from outside, ensuring encapsulation.

The mechanism of a setter works as follows:

1. A private field is declared in the class, for example private String name;.
2. A public method named setName is created, which takes a parameter of the required type.
3. Inside the method, the value of the parameter is assigned to the private field.

Example:

public class Person {
    private String name;

    public void setName(String name) {
        this.name = name;
    }
}

Thus, the setter controls the modification of the object's state, allowing for checks or logic to be added when setting the value, such as null checks or validation.