refactor(common): 允许 pair 中使用 null 值

hamster-core-common/src/main/java/cn/hamster3/mc/plugin/core/common/util/Pair.java

@@ -1,29 +1,22 @@
 package cn.hamster3.mc.plugin.core.common.util;
 
-import org.jetbrains.annotations.NotNull;
-
 import java.io.Serializable;
 import java.util.Objects;
 
 @SuppressWarnings("unused")
 public class Pair<K, V> implements Serializable {
-    @NotNull
     private final K key;
-
-    @NotNull
     private final V value;
 
-    public Pair(@NotNull K key, @NotNull V value) {
+    public Pair(K key, V value) {
         this.key = key;
         this.value = value;
     }
 
-    @NotNull
     public K getKey() {
         return key;
     }
 
-    @NotNull
     public V getValue() {
         return value;
     }
@@ -33,7 +26,7 @@ public class Pair<K, V> implements Serializable {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
         Pair<?, ?> pair = (Pair<?, ?>) o;
-        return key.equals(pair.key) && value.equals(pair.value);
+        return Objects.equals(key, pair.key) && Objects.equals(value, pair.value);
     }
 
     @Override