How to Convert String to int in Java

In Java we can convert string to integer with Integer.parseInt() function.

Syntax:

int in = Integer.parseInt(str); 

Example:

package com.tutorial4u;

public class StringToInt {

       public static void main(String[] args) {

             String str = "4";

              int in = Integer.parseInt(str);   

              System.out.println(in);

       }

}

Output:  4

Note:

In order to use Integer.parseInt() method, we should pass string numbers only. If input string contains other than numbers parseInt() function will throw java.lang.NumberFormatException.

Example:

package com.tutorial4u;

public class StringToInt {

       public static void main(String[] args) {

             String str = "Tutorial4u";

              int in = Integer.parseInt(str);   

              System.out.println(in);

       }

}

Output: 

Exception in thread "main" java.lang.NumberFormatException: For input string: "Tutorial4u"

at java.lang.NumberFormatException.forInputString(Unknown Source)

at java.lang.Integer.parseInt(Unknown Source)

at java.lang.Integer.parseInt(Unknown Source)

at com.tutorial4u.StringToInt.main(StringToInt.java:6)