Question

After investigation of code I found:

 <bean id="TestBean" class="com.test.checkDate"
 factory-method="getPreviousDate">
 <constructor-arg value .............

 ...............................

How it can be possible?
Thanks.

Answer 1

From docs

the constructor arguments specified in the bean definition will be
used to pass in as arguments to the constructor of the ExampleBean.
Now consider a variant of this where instead of using a constructor,
Spring is told to call a static factory method to return an instance
of the object:

<bean id="exampleBean" class="examples.ExampleBean"
      factory-method="createInstance">
  <constructor-arg ref="anotherExampleBean"/>
  <constructor-arg ref="yetAnotherBean"/>
  <constructor-arg value="1"/> 
</bean>

<bean id="anotherExampleBean" class="examples.AnotherBean"/>
<bean id="yetAnotherBean" class="examples.YetAnotherBean"/>

---

public class ExampleBean {

    // a private constructor
    private ExampleBean(...) {
      ...
    }

    // a static factory method; the arguments to this method can be
    // considered the dependencies of the bean that is returned,
    // regardless of how those arguments are actually used.
    public static ExampleBean createInstance (
            AnotherBean anotherBean, YetAnotherBean yetAnotherBean, int i) {

        ExampleBean eb = new ExampleBean (...);
        // some other operations...
            return eb;
    }
}

Note that arguments to the static factory method are supplied via
constructor-arg elements, exactly the same as if a constructor had
actually been used. Also, it is important to realize that the type of
the class being returned by the factory method does not have to be of
the same type as the class which contains the static factory method,
although in this example it is. An instance (non-static) factory
method would be used in an essentially identical fashion (aside from
the use of the factory-bean attribute instead of the class attribute),
so details will not be discussed here.