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HMCLCore/src/main/java/org/jackhuang/hmcl/task/Task.java

@@ -194,7 +194,7 @@ public abstract class Task {
         executor().start();
     }
 
-    public final boolean test() throws Exception {
+    public final boolean test() {
         return executor().test();
     }
 

HMCLCore/src/main/java/org/jackhuang/hmcl/util/Lang.java

@@ -182,6 +182,13 @@ public final class Lang {
             return (V) o;
     }
 
+    public static <V> Optional<V> get(List<V> list, int index) {
+        if (index < 0 || index >= list.size())
+            return Optional.empty();
+        else
+            return Optional.ofNullable(list.get(index));
+    }
+
     public static <V> Optional<V> get(Map<?, ?> map, Object key, Class<V> clazz) {
         return convert(map.get(key), clazz);
     }
@@ -248,4 +255,9 @@ public final class Lang {
             return defaultValue;
         }
     }
+
+    public static <T> T nonNull(T... t) {
+        for (T a : t) if (a != null) return a;
+        return null;
+    }
 }