Java Primitive Data Types and Variables
Byte
1 byte data type Value range: −128 to 127
Short
2 byte data type Value range: −32768 to 32767
Float
4 byte data type Value range: 3.4e−038 to 3.4e+038
Integer
4 byte data type Value range: −2,147,483,648 to 2,147,483,647
Double
8 byte data type Value range: 1.7e−308 to 1.7e+038
Long
8 byte data type Value range: 9,223,372,036,854,775,808 to 9,223,372,036,854,755,807
Integer
A data type that can hold whole numbers such as 123 and −96
Immutable
A term to explain that once created, the values cannot be changed.
Character
Data type that stores character constants in the memory, which can hold only a single unicode character. Value range: 'u0000' (or 0) to 'uffff' (or 65,535, inclusive).
Floating Point
Data type used to represent numbers with a fractional part (two words). There are two subtypes.
Boolean
Data type used to store values with two states: true or false.
Parameters
These are the variables that are passed to the methods of a class.
Data Types
These include: Integers: Byte, Short, Int, Long Floating Points: Float, Double Characters Booleans
Constants
Variables whose values remain the same throughout the program. They are also called Literals. Include String, Character, Boolean, and Numeric types.
Local
___ variable. A method stores its temporary state in this variable type. These variables are only visible to the methods in which they are declared; they are not accessible from the rest of the class.
Instance
___ variable. Has values that are unique to each instance of a class. For example, the currentSpeed of one bicycle is independent from the currentSpeed of another.
Static
___ variable. There is exactly one copy of this variable in existence, regardless of how many times the class has been instantiated. For example, the number of gears for a bicycle might be the same number of gears, which will apply to all instances.