Integer.valueOf() vs Integer.parseInt() with Examples
Last Updated :
05 Sep, 2023
Integer.parseInt():
While operating upon strings, there are times when we need to convert a number represented as a string into an integer type. The method generally used to convert String to Integer in Java is parseInt(). This method belongs to Integer class in java.lang package. It takes a valid string as a parameter and parses it into primitive data type int. It only accepts String as a parameter and on passing values of any other data type, it produces an error due to incompatible types. There are two variants of this method:
Syntax:
public static int parseInt(String s) throws NumberFormatException
public static int parseInt(String s, int radix) throws NumberFormatException
Example:
Java
public class GFG {
public static void main(String args[])
{
int decimalExample = Integer.parseInt(" 20 ");
int signedPositiveExample = Integer.parseInt("+ 20 ");
int signedNegativeExample = Integer.parseInt("- 20 ");
int radixExample = Integer.parseInt(" 20 ", 16 );
int stringExample = Integer.parseInt("geeks", 29 );
System.out.println(decimalExample);
System.out.println(signedPositiveExample);
System.out.println(signedNegativeExample);
System.out.println(radixExample);
System.out.println(stringExample);
}
}
|
Output:
20
20
-20
32
11670324
Integer.valueOf():
This method is a static method belonging to the java.lang package which returns the relevant Integer Object holding the value of the argument passed. This method can take an integer or a String as a parameter. But when the given String is invalid, it provides an error. This method can also take in a character as a parameter but the output will be its corresponding Unicode value. This method will always cache values in the range -128 to 127, inclusive, and may cache other values outside of this range. Syntax:
public static Integer valueOf(int a)
public static Integer valueOf(String str)
public static Integer valueOf(String str, int base)
Example:
Java
import java.lang.*;
public class Geeks {
public static void main(String[] args)
{
Integer obj = new Integer( 10 );
System.out.println("Output Value = "
+ obj.valueOf( 85 ));
}
}
|
Output:
Output Value = 85
Differences between Integer.parseInt() and Integer.valueOf()
- Integer.valueOf() returns an Integer object while Integer.parseInt() returns a primitive int.
Java
class Test1 {
public static void main(String args[])
{
String s = " 77 ";
int str = Integer.parseInt(s);
System.out.print(str);
int str1 = Integer.valueOf(s);
System.out.print(str1);
}
}
|
- Both String and integer can be passed a parameter to Integer.valueOf() whereas only a String can be passed as parameter to Integer.parseInt().
Java
class Test3 {
public static void main(String args[])
{
int val = 99 ;
try {
int str1 = Integer.valueOf(val);
System.out.print(str1);
int str = Integer.parseInt(val);
System.out.print(str);
}
catch (Exception e) {
System.out.print(e);
}
}
}
|
- Compilation Error:
prog.java:18: error: incompatible types:
int cannot be converted to String
int str = Integer.parseInt(val);
^
1 error
- Integer.valueOf() can take a character as parameter and will return its corresponding unicode value whereas Integer.parseInt() will produce an error on passing a character as parameter.
Java
class Test3 {
public static void main(String args[])
{
char val = 'A' ;
try {
int str1 = Integer.valueOf(val);
System.out.print(str1);
int str = Integer.parseInt(val);
System.out.print(str);
}
catch (Exception e) {
System.out.print(e);
}
}
}
|
- Compilation Error:
prog.java:18: error: incompatible types:
char cannot be converted to String
int str = Integer.parseInt(val);
^
1 error
Table of difference
Integer.parseInt() |
Integer.valueOf() |
It can only take a String as a parameter. |
It can take a String as well as an integer as parameter. |
It returns a primitive int value. |
It returns an Integer object. |
When an integer is passed as parameter, it produces an error due to incompatible types |
When an integer is passed as parameter, it returns an Integer object corresponding to the given parameter. |
This method produces an error(incompatible types) when a character is passed as parameter. |
This method can take a character as parameter and will return the corresponding unicode. |
This lags behind in terms of performance since parsing a string takes a lot of time when compared to generating one. |
This method is likely to yield significantly better space and time performance by caching frequently requested values. |
If we need the primitive int datatype then Integer.parseInt() method is to be used. |
If Wrapper Integer object is needed then valueOf() method is to be used. |
Share your thoughts in the comments
Please Login to comment...