Which of the following is NOT a primitive data type in Java?

Concept

Java separates its built-in primitive value types from reference types. Primitive variables directly hold values in one of eight language-defined categories: byte, short, int, long, float, double, char, and boolean.

Class types such as String are reference types: their variables refer to objects rather than belonging to the primitive set.

Application

Classify each offered value by that definition:

• boolean belongs to the primitive set and represents the truth values true and false.

• byte belongs to the primitive set and represents an 8-bit signed integral value.

• double belongs to the primitive set and represents a 64-bit floating-point value.

• String is a class in java.lang, so a String variable is a reference to an object.

Cross-check

The Java Language Specification lists boolean and the numeric types, including byte and double, as primitive types; String is declared as a class rather than included in that list.

Result

Therefore, String is the value that is not a primitive data type in Java.