Primitive Data Types are simple non-object data types. : Primitive Data Types « Java Source And Data Type « SCJP

1. SCJP
2. Java Source And Data Type
3. Primitive Data Types

Java's primitive data types are

 boolean
 char
 byte
 short
 int
 long
 float
 double


Number types (both integer and floating point types) are all signed.

For integer types the sequence from small to big is byte, short, int, long.
doubles are bigger than floats.
boolean can be only true or false. 
The char type contains a single, 16-bit Unicode character. 

 
 
public class MainClass{
    public static void main(String[] argv){
        byte b;
        short s;
        int i;
        long l;
        float f;
        double d;
        char c;
        boolean bool;
    }
}