Java Integer valueOf() Method

The valueOf() method is a static method which returns the relevant Integer Object holding the value of the argument passed. The argument can be a primitive data type, String, etc. There are three different types of Java valueOf() method which can be differentiated depending on its parameter.

These are:

Java Integer valueOf(int i) Method
Java Integer valueOf(String s) Method
Java Integer valueOf(String s, int radix) Method

1. Java Integer valueOf(int i) Method

The valueOf(int i) method of Java Integer class returns an Integer instance representing the specified int value. This method will always accept values in the range -128 to 127 and may cache other values outside of this range.

2. Java Integer valueOf(String s) Method

The valueOf(String s) is an inbuilt method of Java which is used to returns an Integer object holding the value of the specified string. The argument is interpreted as a signed decimal integer. In other words, this method returns an Integer object equal to the value of:

3. Java Integer valueOf(String s, int radix) Method

The valueOf(String s, int radix) method is used to return an Integer object holding the value extracted from the specified string when parsed with the radix given by the second argument. In other words, this method returns an Integer object equal to the value of:

Syntax:

Following are the declaration of valueOf() method:

public static Integer valueOf(int i)
public static Integer valueOf(String s) throws NumberFormatException
public static Integer valueOf(String s, int radix) throws NumberFormatException

Parameter:

DataType	Parameter	Description	Required/Optional
int	i	It is an int value specified by the user and used in converting the Integer object.	Required
String	s	It is a type of String which will be parsed into an integer object.	Required
int	radix	This is of integer type and used in converting the string object.	Required

Returns:

Method	Returns
valueOf(int i)	Returns an Integer instance holding the value of the specified parameter int i.
valueOf(String s)	Returns an Integer instance holding the value represented by the string argument.
valueOf(String s, int radix)	Returns an Integer instance holding the value represented by the string argument in the specified radix.

Exceptions:

NumberFormatException: It throws exception when the input String with respect to specified radix is not a parsable int.

Compatibility Version:

Java 1.5 and above

Example 1

public class IntegerValueOfExample1 {
	@SuppressWarnings("static-access")
	public static void main(String[] args) {
		Integer a = 35;
		Integer b = -45;		   
	      //It returns a Integer instance representing the specified int value 
	      System.out.println("Value = " + a.valueOf(2));
	      System.out.println("Value = " + b.valueOf(-5));
	}
}

Test it Now

Output:

Value = 2
Value = -5

Example 2

public class IntegerValueOfExample2 {
	@SuppressWarnings("static-access")
	public static void main(String[] args) {
	  Integer i = 10;		 
        String str1 = "355";
        String str2 = "-355";
        // It will return  a Integer instance representing  the specified string
        System.out.println("Output Value = " + i.valueOf(str1));
        System.out.println("Output Value = " + i.valueOf(str2));
	}
}

Test it Now

Output:

Output Value = 355
Output Value = -355

Example 3

public class IntegerValueOfExample3 {
		public static void main(String[] args)throws NumberFormatException { String strValue = "234";
			System.out.print("Desired Value is: "+strValue);			
			int radix = 8;
			System.out.print("\nBase Number is: "+radix);			
			// print the value in decimal format
			System.out.println("\nInteger Value: " + Integer.valueOf(strValue, radix));
		}
}

Test it Now

Output:

Desired Value is: 234
Base Number is: 8
Integer Value: 156

Example 4

import java.util.Scanner;
public class IntegerValueOfExample4 {
	public static void main(String[] args)throws NumberFormatException {
		//Input desired value from the console
		System.out.print("Enter Desired Value: ");
		Scanner scan = new Scanner(System.in);
		String strValue = scan.nextLine();
		//Input base number from the console		
		System.out.print("Enter Base Number: ");			
		int radix = scan.nextInt();
		scan.close();
		// print the output in decimal format
	   System.out.println("Output Value: " +Integer.valueOf(strValue,	radix));
	}
}

Test it Now

Output:

Enter Desired Value: CDEF
Enter Base Number: 16
Output Value: 52719

Example 5

import java.util.Scanner;
public class IntegerValueOfExample5 {
		public static void main(String[] args)throws NumberFormatException {
			//Enter input from user console
			System.out.print("Enter Desired Value: ");
			Scanner scan = new Scanner(System.in);
			String strVal = scan.nextLine();		
			scan.close();
			//Print the output value in decimal format
			System.out.println("Integer Value:" + Integer.valueOf(strVal));
		}
}

Test it Now

Output:

Enter Desired Value: ABCDEF
Exception in thread "main" java.lang.NumberFormatException: For input string: "ABCDEF"
	at java.base/java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
	at java.base/java.lang.Integer.parseInt(Integer.java:652)
	at java.base/java.lang.Integer.valueOf(Integer.java:983)
	at myPackage.IntegerValueOfExample5.main(IntegerValueOfExample5.java:13)

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