[BAEL-3405] Solving Binary Gap using Recursion (eugenp#8144)

* A quick and practical example of Hexagonal Architecture in Java

* updated code as per eclipse formatter

* [BAEL-3405] Solving Binary Gap using Recursion

* removed java-hexagonal package

Author: nnnkp

algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/binarygap/BinaryGap.java

@@ -0,0 +1,17 @@
+package com.baeldung.algorithms.binarygap;
+
+public class BinaryGap {
+    static int calculateBinaryGap(int n) {
+        return calculateBinaryGap(n >>> Integer.numberOfTrailingZeros(n), 0, 0);
+    }
+
+    static int calculateBinaryGap(int n, int current, int maximum) {
+        if (n == 0) {
+            return maximum;
+        } else if ((n & 1) == 0) {
+            return calculateBinaryGap(n >>> 1, current + 1, maximum);
+        } else {
+            return calculateBinaryGap(n >>> 1, 0, Math.max(maximum, current));
+        }
+    }
+}

algorithms-miscellaneous-5/src/test/java/com/baeldung/algorithms/binarygap/BinaryGapUnitTest.java

@@ -0,0 +1,34 @@
+package com.baeldung.algorithms.binarygap;
+
+import static com.baeldung.algorithms.binarygap.BinaryGap.calculateBinaryGap;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class BinaryGapUnitTest {
+
+    @Test public void givenNoOccurrenceOfBoundedZeros_whenCalculateBinaryGap_thenOutputCorrectResult() {
+
+        int result = calculateBinaryGap(63);
+        assertEquals(0, result);
+    }
+
+    @Test public void givenTrailingZeros_whenCalculateBinaryGap_thenOutputCorrectResult() {
+
+        int result = calculateBinaryGap(40);
+        assertEquals(1, result);
+    }
+
+    @Test public void givenSingleOccurrenceOfBoundedZeros_whenCalculateBinaryGap_thenOutputCorrectResult() {
+
+        int result = calculateBinaryGap(9);
+        assertEquals(2, result);
+    }
+
+    @Test public void givenMultipleOccurrenceOfBoundedZeros_whenCalculateBinaryGap_thenOutputCorrectResult() {
+
+        int result = calculateBinaryGap(145);
+        assertEquals(3, result);
+    }
+
+}