Types of Literals

Basically, a literal is the source code representation of a fixed value. In order to be able to choose the right answer for some exam questions, you must be able to infer the data type of literals that appear in the sample code of those questions:

Literal type	Description	Data type of the literal
Integer	Decimal values with no decimal point Decimal values ended in: l, L Hexadecimal values (0x prefix) Binary values (0b prefix)	long if it ends with L or l: 123L int otherwise: 123, 0x1A, 0b110
Floating-point	Decimal values with a decimal point or using scientific notation Decimal values ended in: f, F, d, D	float if it ends with F or f: 1.3f, 2e3f double if it ends with D or d: 1.3d, 2e3d double otherwise: 1.3, 2e3
Character	Values between single quotes (may contain Unicode characters)	char: 'A', '\u0041'
String	Values between double quotes (may contain Unicode characters)	String: "ABC", "\u0041BC"
Class	Any type name + .class It refers to the object that represents the type itself	The object’s class, e.g.: String.class

Undescores in Numeric Literals

From Java version 7 on, it’s possible to use underscores in numeric literals to improve legibility. They can appear anywhere between the digits of the literal: