Default type for number in java

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Why is default type for number in Java int? As in this example:

class TestClass {
    public static void main(String args[] ) throws Exception {
        A a = new A();
        a.test(5);
    }
}
class A{
    void test(short a){
        System.out.println("Short");
    }
    void test(int a){
        System.out.println("Integer");
    }
    void test(byte a){
        System.out.println("Byte");
    }
}

It prints Integer.. My question is "Why is default type for a number int in Java"?

What I have tried:

Default type for numerical value

Posted 20-Mar-18 23:36pm

Akshit Gupta

Updated 20-Mar-18 23:52pm

v2

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3 solutions

Solution 2

Um.
Here is a clue:

Java

int i = sc.nextInt();
...
a.test(i);

You specifically declare i as an integer, so pretty understandably, it treats it as an integer!

Posted 20-Mar-18 23:45pm

OriginalGriff

Comments

Akshit Gupta 21-Mar-18 5:52am

Sir I modified the code to pass 5 instead of int i.. I am getting Integer

OriginalGriff 21-Mar-18 6:13am

"int i = ..."
Declares "i" as an integer. Anything you put into an integer variable will be ... an integer!

Solution 3

Your code doesn't prove that.
You are passing an int to test overloads.
As matter of fact, Java is strongly typed: variables have not a default type, they do have their assigned type.

Posted 20-Mar-18 23:46pm

CPallini

Comments

Akshit Gupta 21-Mar-18 5:52am

Sir I modified the code to pass 5 instead of int i.. I am getting Integer

CPallini 21-Mar-18 8:38am

5 is a literal.
See
https://en.wikibooks.org/wiki/Java_Programming/Literals

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Jochen Arndt · Accepted Answer · 2018-03-20T23:44:00

Solution 1

You are calling A.test() passing the integer i. That is not a default type but defined by your code:

Java

int i = sc.nextInt();

[EDIT]

Quote:
Sir I modified the code to pass 5 instead of int i.. I am getting Integer

5 is a numerical integer literal.
Yes, when there is no type hint in the literal, it is an int.
If it has an 'L' postfix, it is a long:

a.test(5L);

If the literal contains a period or an exponent, it is a double.
If it has an 'F' postfix, it is a float.

If you want to treat it as different type you can also use casting:

a.test((short)5);

[/EDIT]

Posted 20-Mar-18 23:44pm

Jochen Arndt

Updated 21-Mar-18 0:04am

v2

Comments

Akshit Gupta 21-Mar-18 5:52am

Sir I modified the code to pass 5 instead of int i.. I am getting Integer

Jochen Arndt 21-Mar-18 6:04am

See my updates answer.
However, editing a question by removing portions that are referenced by solutions is not good style. Others reading the question and answers later might not get that. It is better to let the initial code stay (e.g. by commenting) it and indicate newly added lines like I have done in my updated answer.