Page 69 - CA_Blue( J )_Class9
P. 69
Type Size Default value Example
char 2 bytes \u0000 char c='a';
char d= '\u0041';
Java uses Unicode system not ASCII code system and to represent Unicode system 8 bits is not enough to represent
all characters so java uses 16 bits or 2 bytes for characters.
Boolean Type
The boolean data type is used to store only two possible values: true and false. This data type is used for simple
flags that track true/false conditions. The boolean data type specifies one bit of information.
Type Size Default value Range of values that Example
can be stored
boolean 1 bit false true or false boolean a=true;
Note: 1. Integer type and Float type are Numeric data types.
2. Character type and Boolean type are Non-numeric Data types.
4.5.2 Non-Primitive Data Type
They are also called Reference Data Types or Composite Data types. They contain a memory address of variable
value because the reference types won’t store the variable value directly in memory. They are defined by the
programmer according to the requirement of the program. Different types of Non-Primitive data types are strings,
objects, arrays and interfaces.
4.5.3 Difference between Primitive Data Type and Non-Primitive Data Type
Primitive Data Type Non-Primitive Data Type
1. They are built-in data types. They are used defined data types.
2. There are 8 Primitive data types. There are mainly 4 types of non-Primitive data types.
3. To use them “new” operator is not required. Use of “new” operator is mandatory for creating
instances.
4. The size of a primitive type depends on the data type. Size of non-primitive types may vary.
5. Primitive data types hold only single values. The non-primitive data types are used to store the
group of values.
4.6 VARIABLE
A variable is a name given to a space in computer memory to store a value. In other words, it is a reference to a
memory location where data is held. The term "variable" comes from the combination of "vary" and "able," meaning
its value can change during the program's execution. Variables can take different values at various points, depending
on the logic of the program. You might be wondering, what is the difference between an identifier and a variable? An
identifier is a name used to uniquely identify an entity (such as a function, class, or variable) in the program. It is a
general term that encompasses variables, functions, constants, and more. On the other hand, a variable is a specific
type of identifier that refers to a memory location used to store data that can change as the program runs.
4.6.1 Declaring a Variable
Before using a variable in Java, it must first be declared. If a variable is not declared, it cannot be used, and
attempting to do so will result in a compile-time error.
Values and Types 67

