// https://www.hackerrank.com/challenges/java-lambda-expressions/problem public class JavaLambdaExpression { private interface PerformOperation { boolean check(int number); } private static class MyMath { public static PerformOperation isOdd() { return (int a) -> a % 2 != 0; } public static PerformOperation isPrime() { return (int number) -> { if(number == 1) return false; for (int index = 2 ; index * index <= number ; index++) { if (number % index == 0) { return false; } } return true; }; } public static PerformOperation isPalindrome() { return (int a) -> { String number = a + ""; String reverse = new StringBuilder(number).reverse().toString(); return number.equals(reverse); }; } } }