Java Data Types (Primitive)

 Java data types

As the name suggests, data types in Java specify the type of data that can be stored in Java variables.

Java is a static type language. This means that all variables must be declared before they can be used.

int speed; 

Here the speed is a variable and the data type of the variable is int.

The int data type determines that the speed variable can only contain integers.

There are 8 predefined data types in the Java programming language, called primitive data types.

Note: Besides the primitive data types, there are also referenced types (object type).

8 primitive data types

1.boolean type

  • The Boolean data type has two possible values, true or false.
  • Default: false.
  • They are generally used for true / false conditions.

Example 1: Java Boolean Data Type

class Main {
  public static void main(String[] args) {
    	
    boolean flag = true;
    System.out.println(flag);    // prints true
  }
}

2.byte type

  • The byte data type can have values ​​between -128 and 127 (8-bit signed two's complement integer).
  • If it is certain that a variable's value will be between -128 and 127, then it is used in place of int to save memory.
  • Default: 0

Example 2: Java Byte Data Type

class Main {
  public static void main(String[] args) {

    byte range;
    range = 124;
    System.out.println(range);    // prints 124
  }
}

3.short type

  • The short data type in Java can have values ​​between -32768 and 32767 (16-bit signed two's complement integer).
  • If it is certain that a variable's value will be between -32768 and 32767, then it is used instead of other integer data types (int, long).
  • Default: 0

Example 3: Java short data type

class Main {
  public static void main(String[] args) {
    	
    short temperature;
    temperature = -200;
    System.out.println(temperature);  // prints -200
  } 
}

4.type int

  • The int data type can have values ​​between -231 and 231-1 (32-bit signed two's complement integer).
  • If you are using Java 8 or later, you can use an unsigned 32-bit integer. This will have a minimum value of 0 and a maximum value of 232-1. To learn more, see How to use unsigned integer in java 8?
  • Default: 0

Example 4: Java int data type

class Main {
  public static void main(String[] args) {
    	
    int range = -4250000;
    System.out.println(range);  // print -4250000
  }
}

5.long type

  • The long data type can have values ​​between -263 and 263-1 (64-bit signed two's complement integer).
  • If you are using Java 8 or later, you can use an unsigned 64-bit integer with a minimum value of 0 and a maximum value of 264-1.
  • Default: 0

Example 5: long java data type

class LongExample {
  public static void main(String[] args) {
    	
    long range = -42332200000L;
    System.out.println(range);    // prints -42332200000
  }
}

Notice the use of L at the end of -42332200000. This means that it is an integral literal of type long. You will learn more about full literals later in this article.

6.dual type

  • The double data type is a 64-bit double-precision floating point.
  • It should never be used for specific values ​​such as currency.
  • Default: 0.0 (0.0d)

Example 6: Double Java data type

class Main {
  public static void main(String[] args) {
    	
    double number = -42.3;
    System.out.println(number);  // prints -42.3
  }
}

7.float type

  • The float data type is a 32-bit single-precision floating point. Learn more about single precision and double precision floating point if you are interested.
  • It should never be used for specific values ​​such as currency.
  • Default value: 0.0 (0.0f)

Example 7: Java float data type

class Main {
  public static void main(String[] args) {
    	
    float number = -42.3f;
    System.out.println(number);  // prints -42.3
  }
}

Note that we used -42.3f instead of -42.3 in the above program. This is because -42.3 is a double literal.

To tell the compiler to treat -42.3 as a float rather than a double, you need to use f or F.

If you want to know more about single precision and double precision

8.character type

  • It is a 16-bit Unicode character.
  • The minimum value of the char data type is '\u0000' (0) and the maximum value of is'\uffff'.
  • Default:'\u0000'

Example 8: Java char data type

class Main {
  public static void main(String[] args) {
    	
    char letter = '\u0051';
    System.out.println(letter);  // prints Q
  }
}

Here the Unicode value of Q is  \u0051.  Therefore, we get Q as the output.

Here is another example:

class Main {
  public static void main(String[] args) {
    	
    char letter1 = '9';
    System.out.println(letter1);  // prints 9
    	
    char letter2 = 65;
    System.out.println(letter2);  // prints A

  }
}

Here, we have assigned 9 as a character (specified by single quotes) to the variable letter1. However, the variable letter2 is assigned to 65 as an integer (without single quotes).

Therefore, A is printed on the output. This is because Java treats characters as integral types and the ASCII value of A is 65. Learn more about ASCII

String type

Java also supports strings through the java.lang.String class. Strings in Java are not primitive types. Instead, they are objects. For example,

String myString = "Java Programming";

Here, myString is an object of the String class. To learn more

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