Byte, Short, Integer, and Long

• The Byte,Short,Integer, and Long classes are wrappers for byte, short, int, and long integer types, respectively.
• Their constructors are as follows:

Byte(byte num)

Byte(String str) throws NumberFormatException

Short(short num)

Short(String str) throws NumberFormatException

Integer(int num)

Integer(String str) throws NumberFormatException

Long(long num)

Long(String str) throws NumberFormatException

• All these objects are constructed from either number or String which contains a valid whole number

The constants defined by these objects are as follows:

The methods defined by Byte are as follows:

Methods defined by Short are as follows

Methods defined by Integer are as follows

Methods defined by Iong are as follows:

Converting Numbers to and from Strings

• One of the significant feature of java is to converting the string representation of a number in to its corresponding type format by using the following methods

parseByte( ) //converts in to Byte type

parseShort( ) //converts in to Short type

parseInt( )//converts in to int type

parseLong( )//coverts in to long type

/* This program sums a list of numbers entered
 by the user. It converts the string representation
 of each number into an int using parseInt().
*/
import java.io.*;
public class ParseDemo 
{
 public static void main(String args[]) throws IOException
 {
 // create a BufferedReader using System.in
 BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
 String str;
 int i;
 int sum=0;
 System.out.println("Enter numbers, 0 to quit.");
 do 
 {
 str = br.readLine();
 try 
 {
 i = Integer.parseInt(str);
 } 
   catch(NumberFormatException e)
 {
 System.out.println("Invalid format");
 i = 0;
 }
 sum += i;
 System.out.println("Current sum is: " + sum);
 } while(i != 0);
 }
}

Input: Input:

131hk23412345

0 0

Output: Output:

Enter numbers, 0 to quit. Enter numbers, 0 to quit.

Invalid format Invalid format

Current sum is: 0 Current sum is: 0

• The Integer and Long classes also provide the methods toBinaryString( ), toHexString( ), and toOctalString( ), which convert a value into a binary, hexadecimal , or octal string, respectively.

/* Convert an integer into binary, hexadecimal,
 and octal.
*/
public class StringConversions 
{
 public static void main(String args[]) 
 {
 int num = 19648;
 System.out.println(num + " in binary: " + Integer.toBinaryString(num));
 System.out.println(num + " in octal: " + Integer.toOctalString(num));
   System.out.println(num + " in hexadecimal: " + Integer.toHexString(num));
 }
}

Output:

19648 in binary: 100110011000000

19648 in octal: 46300

19648 in hexadecimal: 4cc0