why is parseint used in java code example

Example: parseints(str) java

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); 
  
        // Uncomment the following code to check 
        // NumberFormatException 
  
        //   String invalidArguments = ""; 
        //   int emptyString = Integer.parseInt(invalidArguments); 
        //   int outOfRangeOfInteger = Integer.parseInt("geeksforgeeks",29); 
        //   int domainOfNumberSystem = Integer.parseInt("geeks",28); 
  
        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