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”.)