Java - Integer valueOf(String s) method

Description

The Java Integer valueOf(String s) method returns an Integer object holding the value of the specified String s.

Declaration

Following is the declaration for java.lang.Integer.valueOf() method

public static Integer valueOf(String s) throws NumberFormatException

Parameters

s − This is the string to be parsed.

Return Value

This method returns an Integer object holding the value represented by the string argument.

Exception

NumberFormatException − if the string cannot be parsed as an integer.

Getting Integer from a String containing Positive int Value Example

The following example shows the usage of Integer valueOf(String s) method to get the Integer object using the specified String having an int value. We've created a String variable and assigned it a positive int value. Then using valueOf() method, we're getting the object and printing it.

package com.tutorialspoint;
public class IntegerDemo {
   public static void main(String[] args) {
      String s = "170";
      System.out.println("String = " + s);
    
      /* returns the Integer object of the given string */
      System.out.println("valueOf = " + Integer.valueOf(s));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

String = 170
valueOf = 170

Getting Integer from a String containing Negative int Value Example

The following example shows the usage of Integer valueOf(String s) method to get the Integer object using the specified String having an int value. We've created a String variable and assigned it a negative int value. Then using valueOf() method, we're getting the object and printing it.

package com.tutorialspoint;
public class IntegerDemo {
   public static void main(String[] args) {
      String s = "-170";
      System.out.println("String = " + s);
    
      /* returns the Integer object of the given string */
      System.out.println("valueOf = " + Integer.valueOf(s));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

String = -170
valueOf = -170

Facing Exceptio while Getting Integer from a String containing Octal Value Example

The following example shows the usage of Integer valueOf(String s) method to get the Integer object using the specified String having an int value. We've created a String variable and assigned it an invalid int value. Then using valueOf() method, we're trying to get the object and printing it. It will throw NumberFormatException.

package com.tutorialspoint;
public class IntegerDemo {
   public static void main(String[] args) {
      String s = "0x170";
      System.out.println("String = " + s);
    
      /* returns the Integer object of the given string */
      System.out.println("valueOf = " + Integer.valueOf(s));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

String = 0x170
Exception in thread "main" java.lang.NumberFormatException: For input string: "0x170"
	at java.lang.NumberFormatException.forInputString(Unknown Source)
	at java.lang.Integer.parseInt(Unknown Source)
	at java.lang.Integer.valueOf(Unknown Source)
	at com.tutorialspoint.IntegerDemo.main(IntegerDemo.java:11)