Sybex OCP 11 Programmer I. Chapter 2 review question 8. Defaults for long and float

[Oksana Cherniavskaia]

Hello Jeanne and Scott.
I see that in your book in table “Table 2.3 Default initialization values by type” it is stated that default for long is 0, NOT 0L and default for float is 0.0, not 0.0f.
Nevertheless in Chapter 2 quiz question 8 option class variable of type long defaults to 0 considered to be incorrect and option  class variable of type long defaults to 0L . considered to be correct. It is confusing a bit.

Which of the following are true? (Choose all that apply.)
A class variable of type boolean defaults to 0 .
A class variable of type boolean defaults to false .
A class variable of type boolean defaults to null .
A class variable of type long defaults to null .
A class variable of type long defaults to 0L .
A class variable of type long defaults to 0 .
None of the above
Excerpt From: Boyarsky, Jeanne. “OCP Oracle Certified Professional Java SE 11 Programmer I Study Guide”.

[Mikalai Zaikin]

I agree, 0L; is not the same as 0;

public class C {	
	long longVar; // default 0L
	int intVar  = longVar;   // fails
	int intVar1 = 0L;   // fails
...

[Campbell Ritchie]

The official version, which comes from the Java® Language Specification (=JLS) is,

Each class variable, instance variable, or array component is initialized with a default value when it is created . . .

   For type long, the default value is zero, that is, 0L

   For type float, the default value is positive zero, that is, 0.0f.

Remember that the JLS is the definition of the language, so it will be used for any answers in the test; if the JLS doesn't supply the answer, the API documentation will be regarded as correct. Again, that is the official definition of the classes. 
As MZ says, there is a difference between 0L and 0; 0 occupies 32 bits all zero and 0L occupies 64 bits all zero. Similarly for floating‑point primitives, 0.0f occupies 32 bits all zero and 0.0 occupies 64 bits all zero. (Not “negative zero”.)

[Oksana Cherniavskaia]

I would also agree that defaults are 0L and 0f. I guess the table in Jeanne's and Scott's book may be modified to reflect that. ))

[Campbell Ritchie]

Please search because I seem to remember a very similar question some time ago.

[Jeanne Boyarsky]

Right. i don't consider this an error because we are showing the conceptual value here.