diff --git a/Dart/factorial.dart b/Dart/factorial.dart
new file mode 100644
index 0000000..9f33cd7
--- /dev/null
+++ b/Dart/factorial.dart
@@ -0,0 +1,14 @@
+int factorial(int num) {
+  if (num <= 1) {
+    return 1;
+  } else {
+    return num * factorial(num - 1);
+  }
+}
+
+void main() {
+  int number = 5;
+  int factorial = factorial(number);
+
+  print('The factorial of $number is $factorial');
+}
diff --git a/Dart/whileloop.dart b/Dart/whileloop.dart
new file mode 100644
index 0000000..e9984c1
--- /dev/null
+++ b/Dart/whileloop.dart
@@ -0,0 +1,3 @@
+while (!isDone()) {
+  doSomething();
+}
diff --git a/Java/BinarySearch/BinarySearchVariation.java b/Java/BinarySearch/BinarySearchVariation.java
new file mode 100644
index 0000000..b58a121
--- /dev/null
+++ b/Java/BinarySearch/BinarySearchVariation.java
@@ -0,0 +1,27 @@
+public class BinarySearchVariation {
+  public static int indexOfFirstOccurrence(int[] nums, int target) {
+        int low = 0;
+        int high = nums.length - 1;
+
+        while (low <= high) {
+            int mid = (low + high) / 2;
+
+            if (nums[mid] == target && (mid == 0 || nums[mid - 1] != target)) {
+                return mid;
+            } else if (nums[mid] < target) {
+                low = mid + 1;
+            } else {
+                high = mid - 1;
+            }
+        }
+
+        return -1;
+    }
+  public static void main(String[] args){
+          int[] nums = {1, 3, 5, 5, 5, 7, 9};
+        int target = 5;
+
+        int indexOfFirstOccurrence = indexOfFirstOccurrence(nums, target);
+    System.out.println("Index of first occurrence: " + indexOfFirstOccurrence);//2
+  }
+}
diff --git a/Java/BinarySearch/BinarySearchVariationIndexOfLastOccurrence.java b/Java/BinarySearch/BinarySearchVariationIndexOfLastOccurrence.java
new file mode 100644
index 0000000..6419340
--- /dev/null
+++ b/Java/BinarySearch/BinarySearchVariationIndexOfLastOccurrence.java
@@ -0,0 +1,25 @@
+public class BinarySearchVariationIndexOfLastOccurrence {
+  public static int indexOfLastOccurrence(int[] nums, int target) {
+        int low = 0;
+        int high = nums.length - 1;
+
+        while (low <= high) {
+            int mid = (low + high) / 2;
+
+            if (nums[mid] == target && (mid == nums.length - 1 || nums[mid + 1] != target)) {
+                return mid;
+            } else if (nums[mid] <= target) {
+                low = mid + 1;
+            } else {
+                high = mid - 1;
+            }
+        }
+
+        return -1;
+    }
+  public static void main(String [] args){
+  int[] nums = {1, 3, 5, 5, 5, 7, 9};
+        int target = 5;
+        int indexOfLastOccurrence = indexOfLastOccurrence(nums, target);
+        System.out.println("Index of last occurrence: " + indexOfLastOccurrence);//4
+  }
diff --git a/stringexample.dart b/stringexample.dart
new file mode 100644
index 0000000..fcf74a5
--- /dev/null
+++ b/stringexample.dart
@@ -0,0 +1,31 @@
+// Single-line string
+String name = 'Alice';
+
+// Multi-line string using double quotes
+String greeting = "Hello, $name!";
+
+// Multi-line string using triple quotes
+String poem = """
+Roses are red,
+Violets are blue,
+Sugar is sweet,
+And so are you.
+""";
+
+// String interpolation
+print('Your name is $name and your greeting is $greeting.');
+
+// String concatenation
+print('${name} says, "${greeting}"');
+
+// String methods
+String upperName = name.toUpperCase();
+String lowerName = name.toLowerCase();
+String trimmedName = name.trim();
+
+// String comparison
+if (name == 'Alice') {
+  print('Hello, Alice!');
+} else {
+  print('Hello, stranger!');
+}