Which statement about number literals in Java is false?

The statement that integers must be positive is false. In Java, an integer can be both positive and negative. Integer types, such as int, can represent a wide range of values, including negative numbers, zero, and positive numbers. For example, a variable of type int can hold values like -1, 0, and 25.

In contrast, the other statements regarding number literals hold true. For instance, numbers in exponential notation default to type double, indicating that these numbers can include fractions and very large or very small values. Zero is classified as an integer in Java, which can be used in arithmetic operations and comparisons. Additionally, when an integer is specified with a fractional part of .0, it is interpreted as a double due to the presence of the decimal point, which indicates a floating-point representation.

Overall, the assertion that integers can only be positive does not align with the fundamental properties of the integer data types in Java, making it the correct choice for the false statement.