Java Byte Primitive Data Type With Program Example

byte keyword is an 8-bit and smallest integer primitive type in Java. It ranges from -128 to 127 value.

It can be used especially in large-sized arrays to save memory. It is also one of the useful types for dealing with a stream of data from a file. Its default value is 0.

Syntax: 

byte variableName = 2;

Since, byte type supports lowest range of value (-128 to 127). If one tries to assign a larger value to it, then the Java compiler would throw InputMismatchException with the message “Value out of range. Value:”3466″ Radix:10” at runtime.  On other hand, at compile time, assigning a larger value would give an “incompatible type” exception.

Printing Java Byte Type

Byte is a signed type, meaning, it can hold positive and negative numbers. Below is the program to demonstrate the same:

public class ByteExamples {
    public static void main(String[] args) {
        byte bytNum =  67;
        byte negNum = -67;
        System.out.println("Byte positive value :: "+ bytNum);
        System.out.println("Byte negative value :: "+ negNum);

    }
}

Output:

Byte positive value :: 67
Byte negative value :: -67

Java Byte to int

Byte can store lower range of values than int type. It is of 8-bit, on other hand, int type is of 32-bit. Therefore, a java compiler automatically converts byte type to int type, this is termed as implicit typecasting. There are other ways to, such as built-in methods.

1. Using implicit typecasting

We can directly assign a byte value to integer type. It gets automatically converted to byte.

Java program for converting byte to int using implicit typecasting

public class ByteExamples {
    public static void main(String[] args) {
        byte bytNum =  67;
        int num = bytNum;
        System.out.println("By Implicit typecasting :: "+ num);

    }
}

Output:

By Implicit typecasting :: 67

2. Using intValue() method

Byte wrapper class also provides a method named intValue() that returns int value of that byte object. Below is the program.

Java program to convert byte to int using intValue() method

public class ByteExamples {
    public static void main(String[] args) {
        byte bytNum =  67;
        int num = new Byte(bytNum).intValue();
        System.out.println("By intValue :: "+ num);

    }
}

Output:

By intValue :: 67

3. Using toUnsignedInt() method

toUnsignedInt method returns int type by unsigned conversion. It means, the argument for that method can allow byte value as an input ranging from 0 to 255.

Java program to convert byte to int using toUnsignedInt() method

public class ByteExamples {
    public static void main(String[] args) {
        byte bytNum =  67;
        int num = Byte.toUnsignedInt(bytNum);
        System.out.println("By toUnsignedInt :: "+ num);

    }
}

Output:

By toUnsignedInt :: 67

Java int to byte

As we know, a byte can have values ranging from -128 to 127 which is quite lower than int type. If one tries to store a int value to byte type, then a program outputs a lossy conversion. In other words, an int value within the range  between -128 to 127 gets successfully converted to byte type. If the value is not having in the range, then Java cuts-off leftmost 24-bits for byte conversion, in such case, one gets different output then the provided integer type value.

Below program to demonstrate lossy conversion from int to byte

public class ByteExamples {
    public static void main(String[] args) {
        int num =  140;
        byte bytNum = (byte) num;
        System.out.println("data loss while converting int :: "+num+" to byte :: "+ bytNum);

    }
}

Output: 

data loss while converting int :: 140 to byte :: -116

How Java converts larger int value to byte ?

Lets convert the above input value, 140,  to binary form

0000_0000_0000_0000_0000_0000_1000_11000

cut off 24 left most bit

1000_11000

The most significant bit (MSB) is 1 [left most value], meaning the value is negative

remove MSB, we would get = 0001100,
Now calculate 2’s complement, in which first perform invert operation and then add 1 to the value.

now, invert it = 1110011
add 1 to it =                   +1

Output : 1110100

which is equivalent to = 116, since, leftmost bit was 1, so, the final result would be -116

Ways to convert int to byte

1. Explicit typecasting
2. byteValue() method

Java program to convert int to byte using explicit typecasting

public class ByteExamples {
    public static void main(String[] args) {
        int num =  23;
        byte bytNum = (byte) num;
        System.out.println("using typecasting "+ bytNum);

    }
}

Output:

using typecasting 23

Java program to convert int to byte using explicit byteValue method

public class ByteExamples {
    public static void main(String[] args) {
        int num =  23;
        byte bytNum = new Integer(num).byteValue();
        System.out.println("using byteValue "+ bytNum);

    }
}

Output: 

using byteValue 23