PrimitiveTypes

BenchmarkPrimitiveTypes.java

/**
* In this operation we are doing 0 conversions, since we are working only with primitive type
*/
private static void operationWithPrimitiveTypeFunctionInterface(){
   long startTime = System.currentTimeMillis();

   int[] array = initValues();

   IntPredicate predicate = i -> i % 2 == 0;

   for(int primitive : array){
       if(predicate.test(primitive)){
//                System.out.println(primitive);
       }
   }

   long stopTime = System.currentTimeMillis();
   long elapsedTime = stopTime - startTime;
   System.out.println("ElapsedTime operationWithPrimitiveTypeFunctionInterface: " + elapsedTime);
}

/**
* In this operation we are doing 200000000 unintentionally conversions.
*/
private static void operationWithWrapperClass(){
   long startTime = System.currentTimeMillis();

   int[] array = initValues();

   // Here we are doing (unintentionally) 100000000 conversions (auto-unboxing [Integer -> int])
   // since the type parameter of Predicate is Integer and we need to convert to int to make the math operation
   Predicate<Integer> predicate = i -> i % 2 == 0;

   for(int primitive : array){
       // Here we are doing (unintentionally) 100000000 conversions (autoboxing [int -> Integer]) since the type parameter of Predicate is Integer
       if(predicate.test(primitive)){
           System.out.println(primitive);
       }
   }

   long stopTime = System.currentTimeMillis();
   long elapsedTime = stopTime - startTime;
   System.out.println("ElapsedTime operationWithWrapperClass: " + elapsedTime);
}

private static int[] initValues() {
   int[] values = new int[100000000];
   Random random = new Random();
   for (int i = 0; i < values.length; i++) {
       values[i] = random.nextInt(MAX_VALUE);
   }
   return values;
}