diff --git a/w8/Main.java b/w8/Main.java
new file mode 100644
index 0000000..0ef28bf
--- /dev/null
+++ b/w8/Main.java
@@ -0,0 +1,47 @@
+class Pair<K, V> {
+    private final K key;
+    private final V value;
+
+    public Pair(K key, V value) {
+        this.key = key;
+        this.value = value;
+    }
+
+    public K getKey() {
+        return key;
+    }
+
+    public V getValue() {
+        return value;
+    }
+
+    @Override
+    public String toString() {
+        return "(" + key + ", " + value + ")";
+    }
+}
+
+class PairUtil {
+    public static <K, V> Pair<V, K> swapPair(Pair<K, V> pair) {
+        return new Pair<>(pair.getValue(), pair.getKey());
+    }
+}
+
+public class Main {
+    public static void main(String[] args) {
+        Pair<String, Integer> p1 = new Pair<>("age", 20);
+        System.out.println("原始 p1: " + p1);
+        Pair<Integer, String> swappedP1 = PairUtil.swapPair(p1);
+        System.out.println("交换后 p1: " + swappedP1);
+
+        Pair<Integer, Double> p2 = new Pair<>(100, 99.5);
+        System.out.println("\n原始 p2: " + p2);
+        Pair<Double, Integer> swappedP2 = PairUtil.swapPair(p2);
+        System.out.println("交换后 p2: " + swappedP2);
+
+        Pair<String, String> p3 = new Pair<>("key", "value");
+        System.out.println("\n原始 p3: " + p3);
+        Pair<String, String> swappedP3 = PairUtil.swapPair(p3);
+        System.out.println("交换后 p3: " + swappedP3);
+    }
+}
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