Slide 4.10: Primitive data types

Data Types (Cont.)

Primitive Data Types (Cont.)
Other comments related to primitive data types include:

Java uses two bytes (16 bits) for a character because it uses Unicode system, instead of ASCII code system (8 bits).

Java is a statically-typed programming language. It means that all variables must be declared before they are used. That is why we need to declare variable’s type and name.

The String data type is used to store a sequence of characters (text). String values must be surrounded by double quotes. It is so much used and integrated in Java, and it is actually a non-primitive data type, because it refers to an object that has methods that are used to perform certain operations on strings.

Concatenate.java (string concatenation)

 public class Concatenate {
   public static void main( String[ ] args ) {
     String[ ] a = { "", "" };     // Spaces allowed
     String b[ ] = { "", "" };     // Spaces allowed
     Integer   c = 20;
     int       d = 20; 
     String    e = a[0] + a[1] + b[0] + b[1] + c + d;
     System.out.println( e );
   }
 }

Output: Result:

Using the ‘+’ operator is the most common way to concatenate two strings in Java. The operator ‘+’ normally acts as an arithmetic operator unless one of its operands is a String. If so, it converts the other operand to a String before joining the second operand to the end of the first operand.