Basic Datatypes supported in Java

The Java programming language is statically typed, which means that all variables must first be declared before they can be used. This involves stating the variable’s type and name, as you’ve already seen:

<div class="codeblock">
  <br><pre>int gear = 1;</pre><br>
</div>

• byte: The byte data type is an 8-bit signed two’s complement integer. It has a minimum value of -128 and a maximum value of 127 (inclusive). The byte data type can be useful for saving memory in large arrays, where the memory savings actually matters. They can also be used in place of int where their limits help to clarify your code; the fact that a variable’s range is limited can serve as a form of documentation.
• short: The short data type is a 16-bit signed two’s complement integer. It has a minimum value of -32,768 and a maximum value of 32,767 (inclusive). As with byte, the same guidelines apply: you can use a short to save memory in large arrays, in situations where the memory savings actually matters.
• int: By default, the int data type is a 32-bit signed two’s complement integer, which has a minimum value of -2³¹ and a maximum value of 2³¹-1. In Java SE 8 and later, you can use the int data type to represent an unsigned 32-bit integer, which has a minimum value of 0 and a maximum value of 2³²-1. Use the Integer class to use int data type as an unsigned integer. See the section The Number Classes for more information. Static methods like compareUnsigned, divideUnsigned etc have been added to the Integer class to support the arithmetic operations for unsigned integers.
• long: The long data type is a 64-bit two’s complement integer. The signed long has a minimum value of -2⁶³ and a maximum value of 2⁶³-1. In Java SE 8 and later, you can use the long data type to represent an unsigned 64-bit long, which has a minimum value of 0 and a maximum value of 2⁶⁴-1. Use this data type when you need a range of values wider than those provided by int. The Long class also contains methods like compareUnsigned, divideUnsigned etc to support arithmetic operations for unsigned long.
• float: The float data type is a single-precision 32-bit IEEE 754 floating point. Its range of values is beyond the scope of this discussion, but is specified in the Floating-Point Types, Formats, and Values section of the Java Language Specification. As with the recommendations for byte and short, use a float (instead of double) if you need to save memory in large arrays of floating point numbers. This data type should never be used for precise values, such as currency. For that, you will need to use the java.math.BigDecimal class instead. Numbers and Strings covers BigDecimal and other useful classes provided by the Java platform.
• double: The double data type is a double-precision 64-bit IEEE 754 floating point. Its range of values is beyond the scope of this discussion, but is specified in the Floating-Point Types, Formats, and Values section of the Java Language Specification. For decimal values, this data type is generally the default choice. As mentioned above, this data type should never be used for precise values, such as currency.
• boolean: The boolean data type has only two possible values: true and false. Use this data type for simple flags that track true/false conditions. This data type represents one bit of information, but its “size” isn’t something that’s precisely defined.
• char: The char data type is a single 16-bit Unicode character. It has a minimum value of '\u0000' (or 0) and a maximum value of '\uffff' (or 65,535 inclusive).

Simple Example

This example shows the basic use of different primitive data types.

public class BasicDataTypesExample {
    public static void main(String[] args) {
        // byte - 8-bit signed integer
        byte byteValue = 100;

        // short - 16-bit signed integer
        short shortValue = 10000;

        // int - 32-bit signed integer
        int intValue = 100000;

        // long - 64-bit signed integer
        long longValue = 10000000000L;

        // float - single-precision 32-bit floating point
        float floatValue = 10.5f;

        // double - double-precision 64-bit floating point
        double doubleValue = 100.5;

        // char - single 16-bit Unicode character
        char charValue = 'A';

        // boolean - true or false
        boolean booleanValue = true;

        // Printing values
        System.out.println("Byte Value: " + byteValue);
        System.out.println("Short Value: " + shortValue);
        System.out.println("Int Value: " + intValue);
        System.out.println("Long Value: " + longValue);
        System.out.println("Float Value: " + floatValue);
        System.out.println("Double Value: " + doubleValue);
        System.out.println("Char Value: " + charValue);
        System.out.println("Boolean Value: " + booleanValue);
    }
}

Output:

Byte Value: 100
Short Value: 10000
Int Value: 100000
Long Value: 10000000000
Float Value: 10.5
Double Value: 100.5
Char Value: A
Boolean Value: true

Complex Example

This example demonstrates the use of both primitive and non-primitive data types in a more complex scenario involving a basic simulation of a student’s record.

public class ComplexDataTypesExample {
    public static void main(String[] args) {
        // Primitive data types
        int studentId = 12345;
        char grade = 'A';
        double gpa = 3.85;
        boolean isGraduated = false;

        // Non-primitive data types
        String studentName = "John Doe";
        int[] scores = {85, 90, 88, 92, 87};
        Student student = new Student(studentId, studentName, grade, gpa, isGraduated, scores);

        // Displaying student information
        System.out.println("Student Information:");
        System.out.println("ID: " + student.getId());
        System.out.println("Name: " + student.getName());
        System.out.println("Grade: " + student.getGrade());
        System.out.println("GPA: " + student.getGpa());
        System.out.println("Graduated: " + student.isGraduated());
        System.out.println("Scores: " + java.util.Arrays.toString(student.getScores()));
    }
}

class Student {
    private int id;
    private String name;
    private char grade;
    private double gpa;
    private boolean graduated;
    private int[] scores;

    public Student(int id, String name, char grade, double gpa, boolean graduated, int[] scores) {
        this.id = id;
        this.name = name;
        this.grade = grade;
        this.gpa = gpa;
        this.graduated = graduated;
        this.scores = scores;
    }

    // Getter methods
    public int getId() { return id; }
    public String getName() { return name; }
    public char getGrade() { return grade; }
    public double getGpa() { return gpa; }
    public boolean isGraduated() { return graduated; }
    public int[] getScores() { return scores; }
}

Output:

Student Information:
ID: 12345
Name: John Doe
Grade: A
GPA: 3.85
Graduated: false
Scores: [85, 90, 88, 92, 87]

These outputs provide a clear demonstration of how the different data types are used and the kind of results you can expect when running the programs.