# HackerRank Java Lambda Expressions problem solution

In this HackerRank Java Lambda Expressions problem in the java programming language you need to Write the following methods that return a lambda expression performing a specified action:

1. PerformOperation isOdd(): The lambda expression must return true if a number is odd or false if it is even.
2. PerformOperation isPrime(): The lambda expression must return true if a number is prime or false if it is composite.
3. PerformOperation isPalindrome(): The lambda expression must return true if a number is a palindrome or false if it is not.

## HackerRank Java Lambda Expression problem solution.

```import java.io.*;
import java.util.*;
interface PerformOperation {
boolean check(int a);
}
class MyMath {
public static boolean checker(PerformOperation p, int num) {
return p.check(num);
}

PerformOperation isOdd()
{
PerformOperation po = (int a)-> a%2 == 0 ? false : true;
return po;
}
PerformOperation isPrime()
{
PerformOperation po = (int a)->
{
if(a == 1) return true;
else
{
for (int i =  2; i < Math.sqrt(a); i++)
if(a%i == 0) return false;
return true;
}
};
return po;
}
PerformOperation isPalindrome()
{
ArrayList<Integer> aa = new ArrayList<>();
PerformOperation po = (int a)->
{
String str = Integer.toString(a);
String reverse = "";
for(int i = str.length()-1; i >= 0; i--)
{
reverse = reverse + str.charAt(i);
}
if(reverse.equals(str)) return true;
return false;
};
return po;
}
}

public class Solution {

public static void main(String[] args) throws IOException {
MyMath ob = new MyMath();
PerformOperation op;
boolean ret = false;
String ans = null;
while (T--> 0) {
StringTokenizer st = new StringTokenizer(s);
int ch = Integer.parseInt(st.nextToken());
int num = Integer.parseInt(st.nextToken());
if (ch == 1) {
op = ob.isOdd();
ret = ob.checker(op, num);
ans = (ret) ? "ODD" : "EVEN";
} else if (ch == 2) {
op = ob.isPrime();
ret = ob.checker(op, num);
ans = (ret) ? "PRIME" : "COMPOSITE";
} else if (ch == 3) {
op = ob.isPalindrome();
ret = ob.checker(op, num);
ans = (ret) ? "PALINDROME" : "NOT PALINDROME";

}
System.out.println(ans);
}
}
}

```