Java Integer - parseInt() Method

The java.lang.Integer.parseInt() method is used to parse the string argument as a signed integer in the radix specified by the second argument. The characters in the string must all be digits of the specified radix (as determined by whether Character.digit(char, int) returns a nonnegative value), except that the first character may be an ASCII minus sign '-' ('\u002D') to indicate a negative value or an ASCII plus sign '+' ('\u002B') to indicate a positive value. The resulting integer value is returned.

An exception of type NumberFormatException is thrown if any of the following situations occurs:

• The first argument is null or is a string of length zero.
• The radix is either smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX.
• Any character of the string is not a digit of the specified radix, except that the first character may be a minus sign '-' ('\u002D') or plus sign '+' ('\u002B') provided that the string is longer than length 1.
• The value represented by the string is not a value of type int.

Syntax

public static int parseInt(String s,
                           int radix)
                    throws NumberFormatException

Parameters

Return Value

Returns the integer represented by the string argument in the specified radix.

Exception

Throws NumberFormatException, if the string does not contain a parsable int.

Example:

In the example below, the java.lang.Integer.parseInt() method is used to parse the string argument as a signed integer in the specified radix.

import java.lang.*;

public class MyClass {
  public static void main(String[] args) {
    
    //creating a string holding integer value
    String x = "100";
    String y = "6F";

    //creating int value using radix as 2 (binary)
    int p = Integer.parseInt(x, 2);

    //creating int value using radix as 16 (hexadecimal)
    int q = Integer.parseInt(y, 16);

    //printing the string
    System.out.println("The string x is: " + x); 
    System.out.println("The string y is: " + y); 

    //printing the int values 
    System.out.println("The int value p is: " + p);   
    System.out.println("The int value q is: " + q);    
  }
}

The output of the above code will be:

The string x is: 100
The string y is: 6F
The int value p is: 4
The int value q is: 111