Basic Java programs demonstrating different use cases of Lambda expressions.
Simple Lambda Expression for Addition
public class LambdaExample {
public static void main(String[] args) {
// Lambda expression for adding two numbers
MathOperation addition = (a, b) -> a + b;
System.out.println("Addition: " + addition.operation(5, 3));
}
}
interface MathOperation {
int operation(int a, int b);
}Lambda Expression for String Concatenation
public class LambdaExample {
public static void main(String[] args) {
// Lambda expression for string concatenation
StringOperation concat = (str1, str2) -> str1 + str2;
System.out.println("Concatenated String: " + concat.operation("Hello", " World"));
}
}
interface StringOperation {
String operation(String str1, String str2);
}
Lambda Expression with No Parameters
public class LambdaExample {
public static void main(String[] args) {
// Lambda expression with no parameters
GreetingService greetService = () -> System.out.println("Hello, Lambda!");
greetService.sayHello();
}
}
interface GreetingService {
void sayHello();
}
Lambda Expression for Finding Maximum of Two Numbers
public class LambdaExample {
public static void main(String[] args) {
// Lambda expression to find the maximum of two numbers
FindMaximum maxFinder = (a, b) -> a > b ? a : b;
System.out.println("Maximum: " + maxFinder.findMax(4, 7));
}
}
interface FindMaximum {
int findMax(int a, int b);
}Lambda Expression for Filtering Even Numbers
import java.util.Arrays;
import java.util.List;
public class LambdaExample {
public static void main(String[] args) {
List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
// Lambda expression to filter even numbers
numbers.stream().filter(n -> n % 2 == 0).forEach(System.out::println);
}
}Lambda Expression for Sorting a List
import java.util.*;
public class LambdaExample {
public static void main(String[] args) {
List<Integer> numbers = Arrays.asList(5, 3, 8, 1, 2);
// Lambda expression for sorting a list
Collections.sort(numbers, (a, b) -> a - b);
System.out.println("Sorted List: " + numbers);
}
}
Lambda Expression for Iterating Over a List
import java.util.*;
public class LambdaExample {
public static void main(String[] args) {
List<String> names = Arrays.asList("John", "Jane", "Paul", "Anna");
// Lambda expression for iterating over the list
names.forEach(name -> System.out.println(name));
}
}Lambda Expression for Calculating Factorial
public class LambdaExample {
public static void main(String[] args) {
// Lambda expression for calculating factorial
Factorial factorial = n -> {
int result = 1;
for (int i = 1; i <= n; i++) {
result *= i;
}
return result;
};
System.out.println("Factorial of 5: " + factorial.calculate(5));
}
}
interface Factorial {
int calculate(int n);
}
Lambda Expression for String Length Comparison
public class LambdaExample {
public static void main(String[] args) {
// Lambda expression to compare the length of two strings
StringLengthComparator comparator = (str1, str2) -> str1.length() - str2.length();
System.out.println("Length Comparison: " + comparator.compare("apple", "banana"));
}
}
interface StringLengthComparator {
int compare(String str1, String str2);
}Lambda Expression with Multiple Statements
public class LambdaExample {
public static void main(String[] args) {
// Lambda expression with multiple statements
GreetMultiple greet = name -> {
System.out.println("Hello, " + name);
System.out.println("How are you?");
};
greet.sayHello("Alice");
}
}
interface GreetMultiple {
void sayHello(String name);
}
These examples showcase the versatility of Lambda expressions in Java, from simple mathematical operations to more complex data manipulation like filtering and sorting.