getting confused on rule for arithmetic operators

[J Zak]

Hello,

I am currently going through the OCA 8 certification book "Oracle Certified Associate Java SE 8 Programmer I Study Guide: Exam 1Z0-808 (p. 54). Wiley. Boyarsky, Jeanne"

In the "Arithmetic Operators" section of chapter 2, the book states:

All of the arithmetic operators may be applied to any Java primitives, except boolean and String

I am getting a bit confused by this statement because String is not a Java primitive type. Further, the book itself states later than "+" can be used with String to achieve concatenation.

What am I missing here? I would greatly appreciate your guidance in understanding the rule that book stated.

Thanks

[J Zak]

i just reviewed the errata at this link https://www.selikoff.net/java-oca-8-programmer-i-study-guide/  and it states:

In the third to last paragraph, “except boolean and String” should be “except boolean” since String is not a primitive

[Sanjeev Ba]

String is categorized under "Reference types and values" in the spec.
https://docs.oracle.com/javase/specs/jls/se8/html/jls-4.html#jls-4.3.3

It is definitely not a primitive.