Java supports eight different primitive data types.

Whole Numbers: The int, short, long, and byte data types

Java provides four ways to deal with numbers for different applications.

Real Numbers with decimals: The `float` and the `double` data types.

Real whole numbers: The int data type

Characters: The char data type

Any ASCII value that can be represented in the machine is called a character (i.e., a char) . The char data type holds a single character and it must be enclosed inside the single quotes ' ' and represents a numeric value. For example:

> char c = 'a'

> c

'a'

> (int)c

97

The value 97 is obtained by typecasting to an integer the character c. Type casting means to force Java to transform a data type into another data type by specifying the data type inside the parenthesis, as shown (int).  You can find the decimal value for the character 'a' and all the characters on your keyboard in the following table.

The boolean data type

The String 

Java supports an additional data type called `String`. The String is a collection of characters that represent words or phrases.

You can "glue" strings together

This is called concatenation. Concatenation is the process of gluing Strings with any other data type, including objects, such as Strings. The process to concatenate must be done through the '+' operand.

> String x = "hello"      // defining a String x

> String y = "world"      // defining a String y

Let us create another variable, z that will concatenate the value of x and y by using the `+` operator.

> String z = x + y

> z

"helloworld"

But also, you can incorporate more Strings or variables in between,

> z = x+" "+y

"hello world"