Integer

Wrapper Classes for Integer Types in Java

Overview

The wrapper classes for primitive integer types in Java are Byte, Short, Integer, and Long. These classes provide utility methods for working with their respective types and are part of the java.lang package. They also offer boxing and unboxing functionalities for converting between primitive types and objects.

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Key Features of Integer Wrapper Classes

1. Boxing and Unboxing: Automatic conversion between primitive types and wrapper classes.
2. Constants: Constants like MAX_VALUE, MIN_VALUE, POSITIVE_INFINITY, etc., for each type.
3. Utility Methods: Methods for parsing, converting, and performing operations on numeric values.

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Byte, Short, Integer, and Long Wrapper Class Operations

Arithmetic Operations

Operation	Symbol	Example
Addition	+	value + value
Subtraction	-	value - value
Multiplication	*	value * value
Division	/	value / value
Modulo	%	value % value

Relational Operations

Operation	Symbol	Example
Equal to	==	value == value
Not equal to	!=	value != value
Greater than	>	value > value
Less than	<	value < value
Greater than or equal to	>=	value >= value
Less than or equal to	<=	value <= value

Static Methods

Common Static Methods for Byte, Short, Integer, and Long

Method	Description	Example
compare(T, T)	Compares two values of the type T	Integer.compare(5, 10) → Returns -1
parse<Type>(String)	Parses a String as a primitive value of type Type	Integer.parseInt("42") → Returns 42
toString()	Converts the value to its string representation	Integer.toString(42) → Returns "42"
valueOf(String)	Returns the corresponding wrapper class instance from a string value	Integer.valueOf("42") → Returns 42
bitCount()	Returns the number of one-bits in the binary representation of the value.	Integer.bitCount(5) → Returns 2
highestOneBit()	Returns the value of the highest one-bit in the binary representation.	Integer.highestOneBit(5) → Returns 4
lowestOneBit()	Returns the value of the lowest one-bit in the binary representation.	Integer.lowestOneBit(5) → Returns 1
numberOfLeadingZeros()	Returns the number of leading zeros in the binary representation.	Integer.numberOfLeadingZeros(5) → Returns 29
numberOfTrailingZeros()	Returns the number of trailing zeros in the binary representation.	Integer.numberOfTrailingZeros(5) → Returns 0
reverse()	Reverses the bits of the number.	Integer.reverse(5) → Returns 268435456
rotateLeft()	Rotates the bits left by a specified number of positions.	Integer.rotateLeft(5, 1) → Returns 10
rotateRight()	Rotates the bits right by a specified number of positions.	Integer.rotateRight(5, 1) → Returns 2
toOctalString()	Converts an int to an octal string	Integer.toOctalString(10) → Returns "12"
toBinaryString()	Converts an int to a binary string	Integer.toBinaryString(10) → Returns "1010"

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Static Methods for Byte

Method	Description	Example
parseByte(String)	Parses a String to a byte value	Byte.parseByte("10") → Returns 10
toString(byte)	Converts a byte to its string representation	Byte.toString((byte)10) → Returns "10"

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Static Methods for Short

Method	Description	Example
parseShort(String)	Parses a String to a short value	Short.parseShort("20") → Returns 20
toString(short)	Converts a short to its string representation	Short.toString((short)5) → Returns "5"

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Static Methods for Integer

Method	Description	Example
parseInt(String)	Parses a String to an int value	Integer.parseInt("42") → Returns 42
toHexString(int)	Converts an int to a hexadecimal string	Integer.toHexString(255) → Returns "ff"
toBinaryString(int)	Converts an int to a binary string	Integer.toBinaryString(10) → Returns "1010"

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Static Methods for Long

Method	Description	Example
parseLong(String s)	Parses a String to a long value	Long.parseLong("10000000000") → Returns 10000000000
toBinaryString(long l)	Converts a long to a binary string	Long.toBinaryString(10) → Returns "1010"

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Instance Methods

Common Instance Methods for Byte, Short, Integer, and Long

Method	Description	Example
compareTo(T other)	Compares this object with the specified object.	Integer.valueOf(42).compareTo(10) → Returns 1
equals(Object obj)	Compares this object to the specified object.	Integer.valueOf(42).equals(42) → Returns true
byteValue()	Returns the value as a byte.	Integer.valueOf(42).byteValue() → Returns 42
shortValue()	Returns the value as a short.	Integer.valueOf(42).shortValue() → Returns 42
intValue()	Returns the value as an int.	Integer.valueOf(42).intValue() → Returns 42
longValue()	Returns the value as a long.	Integer.valueOf(42).longValue() → Returns 42
floatValue()	Returns the value as a float.	Integer.valueOf(42).floatValue() → Returns 42.0f
doubleValue()	Returns the value as a double.	Integer.valueOf(42).doubleValue() → Returns 42.0

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Instance Methods for Byte

Method	Description	Example
byteValue()	Returns the value as a byte.	Byte.valueOf((byte) 10).byteValue() → Returns 10
compareTo(Byte)	Compares this Byte with another Byte.	Byte.valueOf((byte) 10).compareTo(Byte.valueOf((byte) 5)) → Returns 1
longValue()	Converts the byte to a long value	Byte.valueOf((byte) 10).longValue() → Returns 10L
doubleValue()	Converts the byte to a double value	Byte.valueOf((byte) 10).doubleValue() → Returns 10.0
floatValue()	Converts the byte to a float value	Byte.valueOf((byte) 10).floatValue() → Returns 10.0f

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Instance Methods for Short

Method	Description	Example
shortValue()	Returns the value as a short.	Short.valueOf((short) 5).shortValue() → Returns 5
compareTo(Short)	Compares this Short with another Short.	Short.valueOf((short) 10).compareTo(Short.valueOf((short) 5)) → Returns 1
longValue()	Converts the short to a long value	Short.valueOf((short) 10).longValue() → Returns 10L
doubleValue()	Converts the short to a double value	Short.valueOf((short) 10).doubleValue() → Returns 10.0
floatValue()	Converts the short to a float value	Short.valueOf((short) 10).floatValue() → Returns 10.0f

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Instance Methods for Integer

Method	Description	Example
intValue()	Returns the value as an int.	Integer.valueOf(42).intValue() → Returns 42
compareTo(Integer)	Compares this Integer with another Integer.	Integer.valueOf(42).compareTo(Integer.valueOf(10)) → Returns 1

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Instance Methods for Long

Method	Description	Example
longValue()	Returns the value as a long.	Long.valueOf(42L).longValue() → Returns 42L
compareTo(Long)	Compares this Long with another Long.	Long.valueOf(42L).compareTo(Long.valueOf(10L)) → Returns 1

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Relational Operators and Their Equivalent Methods

Integer value1 = 100; // Can be `Bute`, `Short`, `Integer`, `Long`.
Integer value2 = 200; // Can be `Bute`, `Short`, `Integer`, `Long`.

Operator	Operator Usage	Equivalent Method	Usage
==	value1 == value2; // false	equals(Object)	val.equals(value2); // false
!=	value1 != value2; // true	!equals(Object)	!val.equals(value2); // true
<	value1 < value2; // true	compare(int, int)	Integer.compare(value1, value2) < 0; // true
>	value1 > value2; // false	compare(int, int)	Integer.compare(value1, value2) > 0; // false
<=	value1 <= value2; // true	compare(int, int)	Integer.compare(value1, value2) <= 0; // true
>=	value1 >= value2; // false	compare(int, int)	Integer.compare(value1, value2) >= 0; // false

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public class IntegerWrapperExample {
    public static void main(String[] args) {
        // Integer Examples
        Byte byteValue = Byte.valueOf((byte) 3);
        Short shortValue = Short.valueOf((short) 5);
        Integer intValue = Integer.valueOf(10);
        Long longValue = Long.valueOf(100L);

        // Converting Integer to other types
        System.out.println("Byte as int: " + byteValue.intValue());
        System.out.println("Short as int: " + shortValue.intValue());
        System.out.println("Integer as long: " + intValue.longValue());
        System.out.println("Long as int: " + longValue.intValue());

        // Comparing Integer Types
        int byteCompare = Byte.compare(byteValue, (byte) 4);
        int shortCompare = Short.compare(shortValue, (short) 7);
        int intCompare = Integer.compare(intValue, 12);
        int longCompare = Long.compare(longValue, 200L);

        System.out.println("Byte Comparison Result: " + byteCompare);
        System.out.println("Short Comparison Result: " + shortCompare);
        System.out.println("Integer Comparison Result: " + intCompare);
        System.out.println("Long Comparison Result: " + longCompare);

        // Parsing Strings
        byte parsedByte = Byte.parseByte("10");
        short parsedShort = Short.parseShort("20");
        int parsedInt = Integer.parseInt("30");
        long parsedLong = Long.parseLong("40");

        System.out.println("Parsed Byte: " + parsedByte);
        System.out.println("Parsed Short: " + parsedShort);
        System.out.println("Parsed Integer: " + parsedInt);
        System.out.println("Parsed Long: " + parsedLong);
    }
}

For more: IntegerWrapperClasses.java