Java Byte Class

Last modified: April 13, 2025

The java.lang.Byte class is a wrapper for the primitive byte type. It provides utility methods for handling byte values, including conversion, comparison, and parsing. As part of Java's wrapper class system, Byte allows byte primitives to be used in object-oriented contexts, such as collections and generic classes.

Since Byte is final and immutable, its value cannot be changed after creation. It extends the Number class, inheriting numeric capabilities, and implements the Comparable interface, enabling byte values to be compared within Java collections and sorting mechanisms.

Byte Class Methods

The Byte class provides several static and instance methods for byte manipulation. Some key methods include:

• parseByte(String s) - Converts a string into a byte, throwing a NumberFormatException if the input is invalid.
• valueOf(byte b) - Returns a Byte instance representing the specified byte value.
• byteValue() - Extracts the primitive byte value from a Byte object.
• compare(Byte b1, Byte b2) - Compares two Byte values, returning a negative, zero, or positive result based on their ordering.
• toString() - Converts the Byte object into its string representation.

By integrating these methods, Java ensures seamless conversions between byte primitives, string representations, and object-oriented structures. The Byte class is commonly used in scenarios requiring type safety, numerical comparisons, and storage within data structures.

Creating Byte Objects

Byte objects can be created using static factory methods. The valueOf may cache frequently used values for better performance.

void main() {

    Byte byte1 = Byte.valueOf((byte) 100);
    Byte byte2 = Byte.valueOf("100");

    // Using autoboxing
    Byte byte3 = 100;

    System.out.println("byte1: " + byte1);
    System.out.println("byte2: " + byte2);
    System.out.println("byte3: " + byte3);

    // Comparing objects
    System.out.println("byte1 equals byte2: " + (byte1.equals(byte2)));
    System.out.println("byte2 equals byte3: " + (byte2.equals(byte3)));
}

This example demonstrate show to create Byte objects. Note that due to caching, small byte values (between -128 and 127) may refer to the same object when using valueOf.

Parsing Byte Values

The Byte class provides methods to parse string representations of byte values. The parseByte method converts a string to a primitive byte, while valueOf returns a Byte object. Both methods can throw NumberFormatException for invalid input.

void main() {

    // Parsing decimal strings
    byte b1 = Byte.parseByte("100");
    Byte b2 = Byte.valueOf("100");
    
    // Parsing hexadecimal strings
    byte b3 = Byte.parseByte("A", 16);
    Byte b4 = Byte.valueOf("7F", 16);
    
    System.out.println("b1: " + b1);
    System.out.println("b2: " + b2);
    System.out.println("b3: " + b3); // 10 in decimal
    System.out.println("b4: " + b4); // 127 in decimal
    
    try {
        // This will throw NumberFormatException
        byte b5 = Byte.parseByte("200");
    } catch (NumberFormatException e) {
        System.out.println("Error: " + e.getMessage());
    }
}

This example shows how to parse byte values from strings. The radix parameter allows parsing hexadecimal (base 16) values. Note that "200" is invalid as it exceeds Byte.MAX_VALUE (127), causing NumberFormatException.

Comparing Byte Values

Byte values can be compared using instance methods or static utility methods. The compareTo method compares two Byte objects, while compare compares primitive bytes. Both return negative, zero, or positive values indicating ordering.

void main() {

    Byte byte1 = 50;
    Byte byte2 = 100;
    byte byte3 = 50;
    
    // Instance comparison
    System.out.println("byte1.compareTo(byte2): " + byte1.compareTo(byte2));
    System.out.println("byte1.compareTo(Byte.valueOf(byte3)): " + 
                        byte1.compareTo(Byte.valueOf(byte3)));
    
    // Static comparison
    System.out.println("Byte.compare(byte1, byte2): " + 
                        Byte.compare(byte1, byte2));
    System.out.println("Byte.compare(byte3, byte1.byteValue()): " + 
                        Byte.compare(byte3, byte1.byteValue()));
    
    // Equality comparison
    System.out.println("byte1.equals(byte2): " + byte1.equals(byte2));
    System.out.println("byte1.equals(Byte.valueOf(byte3)): " + 
                        byte1.equals(Byte.valueOf(byte3)));
}

This example demonstrates different ways to compare byte values. The compareTo and compare methods return -1, 0, or 1 for less than, equal to, or greater than comparisons. The equals method checks for exact value equality between objects.

Converting Byte Values

The Byte class extends Number, providing methods to convert byte values to other primitive numeric types. These include intValue, doubleValue, etc. The toString methods convert bytes to string representations.

void main() {

    Byte byteValue = 100;
    
    // Converting to other primitive types
    System.out.println("intValue: " + byteValue.intValue());
    System.out.println("doubleValue: " + byteValue.doubleValue());
    System.out.println("floatValue: " + byteValue.floatValue());
    System.out.println("longValue: " + byteValue.longValue());
    System.out.println("shortValue: " + byteValue.shortValue());
    
    // String conversions
    System.out.println("toString: " + byteValue.toString());
    System.out.println("static toString: " + Byte.toString((byte) 100));
    System.out.println("toHexString: " + 
                        Integer.toHexString(byteValue & 0xFF));
}

This example shows various conversion methods available in the Byte class. While Byte provides basic string conversion, for hexadecimal representation we use Integer.toHexString with proper byte masking to avoid sign extension issues.

Byte Constants and Size

The Byte class defines useful constants for the minimum and maximum values a byte can represent. It also provides the SIZE constant representing the number of bits used to store a byte value (always 8 bits in Java).

void main() {

    System.out.println("Byte.MIN_VALUE: " + Byte.MIN_VALUE);
    System.out.println("Byte.MAX_VALUE: " + Byte.MAX_VALUE);
    System.out.println("Byte.SIZE: " + Byte.SIZE + " bits");
    System.out.println("Byte.BYTES: " + Byte.BYTES + " bytes");
    
    // Demonstrating byte range
    byte minByte = Byte.MIN_VALUE;
    byte maxByte = Byte.MAX_VALUE;
    
    System.out.println("minByte - 1: " + (minByte - 1));
    System.out.println("maxByte + 1: " + (maxByte + 1));
    
    // Binary representation
    System.out.println("MIN_VALUE binary: " + 
                        Integer.toBinaryString(minByte & 0xFF));
    System.out.println("MAX_VALUE binary: " + 
                        Integer.toBinaryString(maxByte & 0xFF));
}

This example demonstrates Byte class constants and byte size information. Note that arithmetic operations on bytes promote them to int, so overflow doesn't occur in the same way as with pure byte operations. The binary representation shows the actual 8-bit pattern when properly masked.

Byte Hash Code and Equality

The Byte class overrides hashCode and equals from Object. The hashCode returns the byte value itself, while equals compares the wrapped byte values. This ensures proper behavior when using Byte objects in collections.

void main() {

    Byte byte1 = 100;
    Byte byte2 = 100;
    Byte byte3 = 50;
    
    // Hash code examples
    System.out.println("byte1.hashCode(): " + byte1.hashCode());
    System.out.println("byte2.hashCode(): " + byte2.hashCode());
    System.out.println("byte3.hashCode(): " + byte3.hashCode());
    
    // Equality examples
    System.out.println("byte1.equals(byte2): " + byte1.equals(byte2));
    System.out.println("byte1.equals(byte3): " + byte1.equals(byte3));
    
    // Using in HashSet
    HashSet<Byte> byteSet = new HashSet<>();
    byteSet.add(byte1);
    byteSet.add(byte2);
    byteSet.add(byte3);
    
    System.out.println("Set size: " + byteSet.size());
    System.out.println("Set contains 100: " + byteSet.contains((byte) 100));
}

This example demonstrates the hashCode and equals behavior of Byte objects. Identical byte values produce the same hash code and are considered equal. The HashSet example shows proper collection behavior due to these implementations.

Byte Decoding and Encoding

The Byte class can be used in conjunction with character encoding operations. While Java's String uses UTF-16 internally, bytes are often used for ASCII or other single-byte character encodings. This example shows basic byte/char conversion.

void main() {

    // ASCII character to byte
    byte letterA = (byte) 'A';
    Byte letterB = (byte) 'B';
    
    System.out.println("letterA: " + letterA);
    System.out.println("letterB: " + letterB);
    
    // Byte to character
    char aChar = (char) letterA;
    char bChar = (char) letterB.byteValue();
    
    System.out.println("aChar: " + aChar);
    System.out.println("bChar: " + bChar);
    
    // String to bytes and back
    String text = "Hello";
    byte[] bytes = text.getBytes();
    
    System.out.print("Bytes: ");
    for (byte b : bytes) {
        System.out.print(b + " ");
    }
    System.out.println();
    
    String reconstructed = new String(bytes);
    System.out.println("Reconstructed: " + reconstructed);
}

This example shows basic conversion between bytes and characters. Note that this simple approach works for ASCII characters (0-127) but may not handle extended character sets properly. For full character encoding support, use appropriate Charset objects with String.getBytes and String constructors.

Source

Java Byte Class Documentation

In this article, we've covered all major aspects of the Java Byte class with practical examples. The Byte wrapper class is essential when byte values need to be treated as objects or when utility methods for byte manipulation are required.

Author

My name is Jan Bodnar, and I am a dedicated programmer with many years of experience in the field. I began writing programming articles in 2007 and have since authored over 1,400 articles and eight e-books. With more than eight years of teaching experience, I am committed to sharing my knowledge and helping others master programming concepts.

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