Long Wrapper Class in Java

The Long class wraps a value of the primitive type long in an object. An object of type Long contains a single field whose type is long.

In addition, this class provides several methods for converting a long to a String and a String to a long, as well as other constants and methods useful when dealing with a long.

Long class Constructors

• Long(long value) - Constructs a newly allocated Long object that represents the specified long argument.
• Long(String s) - Constructs a newly allocated Long object that represents the long value indicated by the String parameter.

Example:

long l = 55;
String str = "45";

// Construct two Long objects
Long x = new Long(l);
Long y = new Long(str);

Long class Methods

A diagram shows a list of APIs/Methods that Long class provides.

In this post, we will learn a few important methods of the Long wrapper class.

toString() methods

• String toString() - Returns a String object representing this Long's value.
• static String toString(long i) - Returns a String object representing the specified long.
• static String toString(long i, int radix) - Returns a string representation of the first argument in the radix specified by the second argument.

Example:

private static void toStringMethods() {
 // toString()
 System.out.println("toString(b) = " + Long.toString(l));

 // toHexString(),toOctalString(),toBinaryString()
 // converts into hexadecimal, octal and binary forms.
 System.out.println("toHexString(b) =" + Long.toHexString(l));
 System.out.println("toOctalString(b) =" + Long.toOctalString(l));
 System.out.println("toBinaryString(b) =" + Long.toBinaryString(l));

}

valueOf() methods

• static Long valueOf(long l) - Returns a Long instance representing the specified long value.
• static Long valueOf(String s) - Returns a Long object holding the value of the specified String.
• static Long valueOf(String s, in - radix) - Returns a Long object holding the value extracted from the specified String when parsed with the radix given by the second argument.

Example:

private static void valueOfMethods() {
 // valueOf(): return Long object
 // an overloaded method takes radix as well.
 Long z = Long.valueOf(l);
 System.out.println("valueOf(b) = " + z);
 z = Long.valueOf(str);
 System.out.println("ValueOf(bb) = " + z);
 z = Long.valueOf(str, 6);
 System.out.println("ValueOf(bb,6) = " + z);
}

parseLong() methods

• static long parseLong(String s) - Parses the string argument as a signed decimal long.
• static long parseLong(String s, int radix) - Parses the string argument as a signed long in the radix specified by the second argument.

Example:

private static void parseLongMethods() {
 // parseLong(): return primitive long value
 // an overloaded method takes radix as well
 long zz = Long.parseLong(str);
 System.out.println("parseLong(bb) = " + zz);
 zz = Long.parseLong(str, 6);
 System.out.println("parseLong(bb,6) = " + zz);

}

rotateLeft() and rotateRight() methods

• static long rotateLeft(long i, int distance) - Returns the value obtained by rotating the two's complement binary representation of the specified long value left by the specified number of bits.
• static long rotateRight(long i, int distance) - Returns the value obtained by rotating the two's complement binary representation of the specified long value right by the specified number of bits.

Example:

private static void rotateMethods() {
 // rotateLeft and rotateRight can be used
 // to rotate bits by specified distance
 long valrot = 2;
 System.out.println("rotateLeft(0000 0000 0000 0010 , 2) =" + Long.rotateLeft(valrot, 2));
 System.out.println("rotateRight(0000 0000 0000 0010,3) =" + Long.rotateRight(valrot, 3));

}

decode() method

• static Long decode(String nm) - Decodes a String into a Long

private static void decodeMethods() {

 // decode() : decodes the hex,octal and decimal
 // string to corresponding long values.
 String decimal = "45";
 String octal = "005";
 String hex = "0x0f";

 Long dec = Long.decode(decimal);
 System.out.println("decode(45) = " + dec);
 dec = Long.decode(octal);
 System.out.println("decode(005) = " + dec);
 dec = Long.decode(hex);
 System.out.println("decode(0x0f) = " + dec);

}

getLong() method

• static Long getLong(String nm) - Determines the long value of the system property with the specified name.
• static Long getLong(String nm, long val) - Determines the long value of the system property with the specified name.
• static Long getLong(String nm, Long val) - Returns the long value of the system property with the specified name.

Example:

private static void getLongMethods() {
 // getLong(): can be used to retrieve
 // long value of system property
 long prop = Long.getLong("sun.arch.data.model");
 System.out.println("getLong(sun.arch.data.model) = " + prop);
 System.out.println("getLong(abcd) =" + Long.getLong("abcd"));

 // an overloaded getLong() method
 // which return default value if property not found.
 System.out.println("getLong(abcd,10) =" + Long.getLong("abcd", 10));
}

intValue,byteValue,shortValue,longValue,doubleValue,floatValue() methods

private static void valueMethods() {
 Long x = new Long(l);
 // xxxValue can be used to retrieve
 // xxx type value from long value.
 // xxx can be int,byte,short,long,double,float
 System.out.println("bytevalue(x) = " + x.byteValue());
 System.out.println("shortvalue(x) = " + x.shortValue());
 System.out.println("intvalue(x) = " + x.intValue());
 System.out.println("longvalue(x) = " + x.longValue());
 System.out.println("doublevalue(x) = " + x.doubleValue());
 System.out.println("floatvalue(x) = " + x.floatValue());
}

There few more methods, refer the comments in below program are self descriptive.

public static void main(String[] args) {
 long l = 55;
 String str = "45";

 // Construct two Long objects
 Long x = new Long(l);
 Long y = new Long(str);

 long value = 45;

 // bitcount() : can be used to count set bits
 // in twos complement form of the number
 System.out.println("Long.bitcount(value)=" + Long.bitCount(value));

 // numberOfTrailingZeroes and numberOfLeaadingZeroes
 // can be used to count prefix and postfix sequence of 0
 System.out.println("Long.numberOfTrailingZeros(value)=" + Long.numberOfTrailingZeros(value));
 System.out.println("Long.numberOfLeadingZeros(value)=" + Long.numberOfLeadingZeros(value));

 // highestOneBit returns a value with one on highest
 // set bit position
 System.out.println("Long.highestOneBit(value)=" + Long.highestOneBit(value));

 // highestOneBit returns a value with one on lowest
 // set bit position
 System.out.println("Long.lowestOneBit(value)=" + Long.lowestOneBit(value));

 // reverse() can be used to reverse order of bits
 // reverseytes() can be used to reverse order of bytes
 System.out.println("Long.reverse(value)=" + Long.reverse(value));
 System.out.println("Long.reverseBytes(value)=" + Long.reverseBytes(value));

 // signum() returns -1,0,1 for negative,0 and positive
 // values
 System.out.println("Long.signum(value)=" + Long.signum(value));

 // hashcode() returns hashcode of the object
 int hash = x.hashCode();
 System.out.println("hashcode(x) = " + hash);

 // equals returns boolean value representing equality
 boolean eq = x.equals(y);
 System.out.println("x.equals(y) = " + eq);

 // compare() used for comparing two int values
 int e = Long.compare(x, y);
 System.out.println("compare(x,y) = " + e);

 // compareTo() used for comparing this value with some
 // other value
 int f = x.compareTo(y);
 System.out.println("x.compareTo(y) = " + f);
}

Output:

toString(b) = 55
toHexString(b) =37
toOctalString(b) =67
toBinaryString(b) =110111
decode(45) = 45
decode(005) = 5
decode(0x0f) = 15
getLong(sun.arch.data.model) = 64
getLong(abcd) =null
getLong(abcd,10) =10
parseLong(bb) = 45
parseLong(bb,6) = 29
rotateLeft(0000 0000 0000 0010 , 2) =8
rotateRight(0000 0000 0000 0010,3) =4611686018427387904
bytevalue(x) = 55
shortvalue(x) = 55
intvalue(x) = 55
longvalue(x) = 55
doublevalue(x) = 55.0
floatvalue(x) = 55.0
valueOf(b) = 55
ValueOf(bb) = 45
ValueOf(bb,6) = 29
Long.bitcount(value)=4
Long.numberOfTrailingZeros(value)=0
Long.numberOfLeadingZeros(value)=58
Long.highestOneBit(value)=32
Long.lowestOneBit(value)=1
Long.reverse(value)=-5476377146882523136
Long.reverseBytes(value)=3242591731706757120
Long.signum(value)=1
hashcode(x) = 55
x.equals(y) = false
compare(x,y) = 1
x.compareTo(y) = 1

Complete Program for Reference

package com.javaguides.corejava.wrapperclasses;

public class LongClassExample {

 static long l = 55;
 static String str = "45";

 private static void toStringMethods() {
  // toString()
  System.out.println("toString(b) = " + Long.toString(l));

  // toHexString(),toOctalString(),toBinaryString()
  // converts into hexadecimal, octal and binary forms.
  System.out.println("toHexString(b) =" + Long.toHexString(l));
  System.out.println("toOctalString(b) =" + Long.toOctalString(l));
  System.out.println("toBinaryString(b) =" + Long.toBinaryString(l));

 }

 private static void valueOfMethods() {
  // valueOf(): return Long object
  // an overloaded method takes radix as well.
  Long z = Long.valueOf(l);
  System.out.println("valueOf(b) = " + z);
  z = Long.valueOf(str);
  System.out.println("ValueOf(bb) = " + z);
  z = Long.valueOf(str, 6);
  System.out.println("ValueOf(bb,6) = " + z);
 }

 private static void parseLongMethods() {
  // parseLong(): return primitive long value
  // an overloaded method takes radix as well
  long zz = Long.parseLong(str);
  System.out.println("parseLong(bb) = " + zz);
  zz = Long.parseLong(str, 6);
  System.out.println("parseLong(bb,6) = " + zz);

 }

 private static void getLongMethods() {
  // getLong(): can be used to retrieve
  // long value of system property
  long prop = Long.getLong("sun.arch.data.model");
  System.out.println("getLong(sun.arch.data.model) = " + prop);
  System.out.println("getLong(abcd) =" + Long.getLong("abcd"));

  // an overloaded getLong() method
  // which return default value if property not found.
  System.out.println("getLong(abcd,10) =" + Long.getLong("abcd", 10));
 }

 private static void decodeMethods() {

  // decode() : decodes the hex,octal and decimal
  // string to corresponding long values.
  String decimal = "45";
  String octal = "005";
  String hex = "0x0f";

  Long dec = Long.decode(decimal);
  System.out.println("decode(45) = " + dec);
  dec = Long.decode(octal);
  System.out.println("decode(005) = " + dec);
  dec = Long.decode(hex);
  System.out.println("decode(0x0f) = " + dec);

 }

 private static void rotateMethods() {
  // rotateLeft and rotateRight can be used
  // to rotate bits by specified distance
  long valrot = 2;
  System.out.println("rotateLeft(0000 0000 0000 0010 , 2) =" + Long.rotateLeft(valrot, 2));
  System.out.println("rotateRight(0000 0000 0000 0010,3) =" + Long.rotateRight(valrot, 3));

 }

 private static void valueMethods() {
  Long x = new Long(l);
  // xxxValue can be used to retrieve
  // xxx type value from long value.
  // xxx can be int,byte,short,long,double,float
  System.out.println("bytevalue(x) = " + x.byteValue());
  System.out.println("shortvalue(x) = " + x.shortValue());
  System.out.println("intvalue(x) = " + x.intValue());
  System.out.println("longvalue(x) = " + x.longValue());
  System.out.println("doublevalue(x) = " + x.doubleValue());
  System.out.println("floatvalue(x) = " + x.floatValue());
 }

 public static void main(String[] args) {
  long l = 55;
  String str = "45";

  // Construct two Long objects
  Long x = new Long(l);
  Long y = new Long(str);

  toStringMethods();
  decodeMethods();
  getLongMethods();
  parseLongMethods();
  rotateMethods();
  valueMethods();
  valueOfMethods();
  
  
  long value = 45;

  // bitcount() : can be used to count set bits
  // in twos complement form of the number
  System.out.println("Long.bitcount(value)=" + Long.bitCount(value));

  // numberOfTrailingZeroes and numberOfLeaadingZeroes
  // can be used to count prefix and postfix sequence of 0
  System.out.println("Long.numberOfTrailingZeros(value)=" + Long.numberOfTrailingZeros(value));
  System.out.println("Long.numberOfLeadingZeros(value)=" + Long.numberOfLeadingZeros(value));

  // highestOneBit returns a value with one on highest
  // set bit position
  System.out.println("Long.highestOneBit(value)=" + Long.highestOneBit(value));

  // highestOneBit returns a value with one on lowest
  // set bit position
  System.out.println("Long.lowestOneBit(value)=" + Long.lowestOneBit(value));

  // reverse() can be used to reverse order of bits
  // reverseytes() can be used to reverse order of bytes
  System.out.println("Long.reverse(value)=" + Long.reverse(value));
  System.out.println("Long.reverseBytes(value)=" + Long.reverseBytes(value));

  // signum() returns -1,0,1 for negative,0 and positive
  // values
  System.out.println("Long.signum(value)=" + Long.signum(value));

  // hashcode() returns hashcode of the object
  int hash = x.hashCode();
  System.out.println("hashcode(x) = " + hash);

  // equals returns boolean value representing equality
  boolean eq = x.equals(y);
  System.out.println("x.equals(y) = " + eq);

  // compare() used for comparing two int values
  int e = Long.compare(x, y);
  System.out.println("compare(x,y) = " + e);

  // compareTo() used for comparing this value with some
  // other value
  int f = x.compareTo(y);
  System.out.println("x.compareTo(y) = " + f);
 }

}

Output:

toString(b) = 55
toHexString(b) =37
toOctalString(b) =67
toBinaryString(b) =110111
decode(45) = 45
decode(005) = 5
decode(0x0f) = 15
getLong(sun.arch.data.model) = 64
getLong(abcd) =null
getLong(abcd,10) =10
parseLong(bb) = 45
parseLong(bb,6) = 29
rotateLeft(0000 0000 0000 0010 , 2) =8
rotateRight(0000 0000 0000 0010,3) =4611686018427387904
bytevalue(x) = 55
shortvalue(x) = 55
intvalue(x) = 55
longvalue(x) = 55
doublevalue(x) = 55.0
floatvalue(x) = 55.0
valueOf(b) = 55
ValueOf(bb) = 45
ValueOf(bb,6) = 29
Long.bitcount(value)=4
Long.numberOfTrailingZeros(value)=0
Long.numberOfLeadingZeros(value)=58
Long.highestOneBit(value)=32
Long.lowestOneBit(value)=1
Long.reverse(value)=-5476377146882523136
Long.reverseBytes(value)=3242591731706757120
Long.signum(value)=1
hashcode(x) = 55
x.equals(y) = false
compare(x,y) = 1
x.compareTo(y) = 1

References

https://docs.oracle.com/javase/8/docs/api/java/lang/Long.html

Related Wrapper Classes

1. Integer Wrapper Class in Java
2. Long Wrapper Class in Java
3. Float Wrapper Class in Java
4. Double Wrapper Class in Java
5. Boolean Wrapper Class in Java
6. Short Wrapper Class in Java
7. Byte Wrapper Class in Java
8. Character Wrapper Class in Java