How do you get the type of a primitive literal in Java?

Question

I just learned about using "L" after long values to signify that they're long types, just like when you use "f" after float types. I was wondering what happens when you write;

long value = 3;

instead of

long value = 3L;

So I was wondering;

Does the compiler consider 3 an integer and then just convert it implicitly to a long?

Then I tried to check the type of the value "3" by using instanceof (but I can't use it since it is a primitive type) or reflection (getClass(), but obviously I can't because it isn't a reference type). Is there anyway to check what type the value "3" is or is this impossible since Java is statically typed?

Thanks, Bernard

Why not? Please show your code using the answers from that question, and tell how it doesn't work. — DontKnowMuchBut Getting Better, Aug 16 '20 at 13:29
Because the OP is not talking about the type of a *field* but the type of an *expression*. — Jörg W Mittag, Aug 16 '20 at 13:29
We know that the `3` is an int literal; that's a given. And Java automatically casts it to long — DontKnowMuchBut Getting Better, Aug 16 '20 at 13:30
System.out.println(3 == Long.TYPE); Gives me "Incompatible operand types int and Class" — Bernard Borg, Aug 16 '20 at 13:30
@BernardBorg: that's not how the code in the answers work or are written — DontKnowMuchBut Getting Better, Aug 16 '20 at 13:31
@DontKnowMuchButGettingBetter: "We know that the `3` is an int literal; that's a given." – That is *literally* the answer. — Jörg W Mittag, Aug 16 '20 at 13:32
It's not useful to _check_ the type of `3`, because it's always `int`. — Sweeper, Aug 16 '20 at 13:32
@BernardBorg: You can easily check the type of `3` by looking it up in the JLS. — Jörg W Mittag, Aug 16 '20 at 13:36
@JörgWMittag So there isn't anyway to do check the type of primitive literals with code? — Bernard Borg, Aug 16 '20 at 13:38
A literal is literally the value it represents. The literal is composed of a sequence of 'marks' (my term) in source code. You can always determine the type by looking at the marks, and as a programmer you need to know how to do that -- you need to know 3 is an int, 3L is a long int, '3' is a char, and "3" is a string. — user13784117, Aug 16 '20 at 14:03
@BernardBorg: It's not necessarily the case that there is no way. There is just no need. `3` is always `3`. There is no need to check what `3` is because you know what it is. Its value and type is uniquely determined by the sequence of characters that appears in the source code. — Jörg W Mittag, Aug 16 '20 at 14:22

Jörg W Mittag · Answer 1 · 2020-08-16T13:32:51.060

1

According to section 3.10.1 Integer Literals of the Java 14 Language Specification:

An integer literal is of type long if it is suffixed with an ASCII letter L or l (ell); otherwise it is of type int (§4.2.1).

edited Aug 16 '20 at 13:32

answered Aug 16 '20 at 13:31

Jörg W Mittag

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This answers my initial question of whether "3" is int or long, but doesn't answer the question whether or not there is any way to check the type of a primitive value. – Bernard Borg Aug 16 '20 at 13:32
@BernardBorg: again, the answers in the duplicate question answers this "second part" completely. – DontKnowMuchBut Getting Better Aug 16 '20 at 13:33
@BernardBorg: The Java Language Specification tells you the type of `3`. You can check it by looking it up there. – Jörg W Mittag Aug 16 '20 at 13:36
A literal is literally the value it represents. The literal is composed of a sequence of 'marks' (my term) in source code. You can always determine the type by looking at the marks, and as a programmer you need to know how to do that -- you need to know 3 is an int, 3L is a long int, '3' is a char, and "3" is a string. So given you must know this when you write the code, there is no need for runtime facilities to check. – user13784117 Aug 16 '20 at 14:04

How do you get the type of a primitive literal in Java?

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