Data Types:


Primitive Data Type                Reference Type (Non -primitive)

boolean							   class	
byte							   Array[]
char							   interface
short							   enum
int 
long
float
double





Java Data Types

    
Java has two main categories of data types: Primitive Types and Reference Types. Understanding these is fundamental to programming in Java.

    
Primitive Data Types

    
Primitive data types are the most basic data types available in Java. They directly hold the value and are stored directly in memory.

    

        

            

                
Primitive Data Type
                
Size
                
Default Value
            
        
        

            

                
boolean
                
Undefined
                
false
            
            

                
byte
                
1 byte
                
0
            
            

                
char
                
2 bytes
                
'\u0000'
            
            

                
short
                
2 bytes
                
0
            
            

                
int
                
4 bytes
                
0
            
            

                
long
                
8 bytes
                
0L
            
            

                
float
                
4 bytes
                
0.0f
            
            

                
double
                
8 bytes
                
0.0d
            
        
    

    
Reference Data Types

    
Reference data types (also known as object types) don't directly store the value. Instead, they store references (addresses) to objects in memory.

    
For all reference types, the default value is null.

    

        

            

                
Reference Type
                
Default Value
            
        
        

            

                
String
                
null
            
            

                
Arrays
                
null
            
            

                
Classes
                
null
            
            

                
Interfaces
                
null