Write a Java program using Lambda Expression to convert a list of strings to uppercase
The java program that converts a list of strings to uppercase using a lambda expression and a custom functional interface StringConverter. Here's an explanation of the code:
- The ConvertUppercase class is defined, which contains the main method and another method named convertToUpperCase.
- Inside the main method:
- List<String> strings = List.of("Pineapple", "Banana", "Blueberry", "Raspberries", "Grapes");: This line creates an immutable list of strings named strings using the List.of method. It contains a set of strings.
- System.out.println("Given String : " + strings); : This line prints the original list of strings.
- List<String> upperstrings = convertToUpperCase(strings, str -> str.toUpperCase());: This line calls the convertToUpperCase method, passing the strings list as well as a lambda expression str -> str.toUpperCase() as the converter. The lambda expression converts each string to uppercase.
- System.out.println("Convert Uppercase : " + upperstrings);: This line prints the list of strings converted to uppercase.
- The convertToUpperCase method is defined with the following functionality:
- List<String> result = new ArrayList<>();: This line creates an ArrayList to store the converted strings.
- The method iterates through each string in the input list, applies the conversion using the provided converter, and adds the converted string to the result list.
- Finally, the result list containing the converted strings is returned.
- The StringConverter functional interface is defined, which declares a single method named convert that takes a string and returns a string. This interface is used to define the lambda expression for converting strings to uppercase.
Source Code
import java.util.ArrayList;
import java.util.List;
public class ConvertUppercase
{
public static void main(String[] args)
{
List<String> strings = List.of("Pineapple", "Banana", "Blueberry", "Raspberries", "Grapes");
System.out.println("Givent String : "+strings);
List<String> upperstrings = convertToUpperCase(strings, str -> str.toUpperCase());
System.out.println("Convert Uppercase : "+upperstrings);
}
public static List<String> convertToUpperCase(List<String> list, StringConverter converter)
{
List<String> result = new ArrayList<>();
for (String str : list)
{
result.add(converter.convert(str));
}
return result;
}
}
interface StringConverter
{
String convert(String str);
}
Output
Givent String : [Pineapple, Banana, Blueberry, Raspberries, Grapes]
Convert Uppercase : [PINEAPPLE, BANANA, BLUEBERRY, RASPBERRIES, GRAPES]