Facing ambiguity in spring constructors, second constructor is getting called

I’m facing an issue which is producing an output which is not exactly per the norm. I have read that in case of constructor ambiguity the first constructor gets called. But I’m facing a completely different issue.

My class –

public class Addition {
    private int a;
    private int b;
    public Addition() {
        super();
        // TODO Auto-generated constructor stub
    }
    
    public Addition(int a, int b) {
        super();
        this.a = a;
        this.b = b;
        System.out.println("Constructor : int, int");
    }
    
    public Addition(double a, double b) {
        super();
        this.a = (int)a;
        this.b = (int)b;
        System.out.println("Constructor : double, double");
    }
    
    public void doSum() {
        System.out.println("Sum is -> "+(this.a+this.b));
    }

    @Override
    public String toString() {
        return "Addition [a=" + a + ", b=" + b + "]";
    }
    
}

XML file –

<bean class="com.spring.Addition" name="addition1">
    <constructor-arg>
    <value>12</value>
    </constructor-arg>
    <constructor-arg>
    <value>34</value>
    </constructor-arg>
    </bean>

Main code –

Addition addition = (Addition)applicationContext.getBean("addition1");
System.out.println(addition);

Output-

Constructor : double, double
Addition [a=12, b=34]

My only concern here is why is the second constructor getting called here, when (int,int) constructor is defined before the (double,double) constructor?

Answer

You can avoid such ambiguity by specifying the exact data type for constructor, via type attribute as follows:

<bean class="com.spring.Addition" name="addition1">
    <constructor-arg type="int">
        <value>12</value>
    </constructor-arg>
    <constructor-arg type="int">
        <value>34</value>
    </constructor-arg>
</bean>

Advertisement

Answer