Add all 23 GoF design pattern implementations (2026-06-13)

03-behavioral/strategy/Main.java

@@ -0,0 +1,37 @@
+package strategy;
+
+import java.util.Arrays;
+
+/**
+ * Strategy Design Pattern — Runnable Demo
+ * Run: javac strategy/*.java -d out/strategy && java -cp out/strategy strategy.Main
+ * Article: https://ankurm.com/strategy-design-pattern-java/
+ */
+public class Main {
+    public static void main(String[] args) {
+        System.out.println("=== Strategy Design Pattern Demo ===\n");
+
+        int[] data = {64, 34, 25, 12, 22, 11, 90};
+        System.out.println("Input: " + Arrays.toString(data));
+
+        Sorter sorter = new Sorter(new BubbleSort());
+        System.out.println("\n-- BubbleSort --");
+        System.out.println("Sorted: " + Arrays.toString(sorter.sort(data)));
+
+        sorter.setStrategy(new MergeSort());
+        System.out.println("\n-- MergeSort --");
+        System.out.println("Sorted: " + Arrays.toString(sorter.sort(data)));
+
+        sorter.setStrategy(new QuickSort());
+        System.out.println("\n-- QuickSort --");
+        System.out.println("Sorted: " + Arrays.toString(sorter.sort(data)));
+
+        System.out.println("\n-- Runtime strategy selection (simulating large dataset) --");
+        int size = 10_000;
+        SortStrategy chosen = size > 1000 ? new QuickSort() : new BubbleSort();
+        sorter.setStrategy(chosen);
+        System.out.println("  Chose " + chosen.getName() + " for size=" + size);
+
+        System.out.println("\n=== Demo complete ===");
+    }
+}