[Feature] 让Java下载页面可以同时下载多个Java (#5394)

Co-authored-by: Glavo <zjx001202@gmail.com>

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

@@ -22,6 +22,7 @@ import javafx.beans.property.DoubleProperty;
 import javafx.beans.property.ReadOnlyDoubleProperty;
 import javafx.beans.property.SimpleDoubleProperty;
 import org.jackhuang.hmcl.event.EventManager;
+import org.jackhuang.hmcl.util.Result;
 import org.jackhuang.hmcl.util.function.ExceptionalConsumer;
 import org.jackhuang.hmcl.util.function.ExceptionalFunction;
 import org.jackhuang.hmcl.util.function.ExceptionalRunnable;
@@ -784,6 +785,37 @@ public abstract class Task<T> {
         return whenComplete(executor, (exception -> action.execute(getResult(), exception)));
     }
 
+    public Task<Result<T>> wrapResult() {
+        return new Task<Result<T>>() {
+            {
+                setSignificance(TaskSignificance.MODERATE);
+            }
+
+            @Override
+            public void execute() throws Exception {
+                if (isDependentsSucceeded() != (Task.this.getException() == null))
+                    throw new AssertionError("When whenComplete succeeded, Task.exception must be null.", Task.this.getException());
+
+                if (isDependentsSucceeded()) {
+                    setResult(Result.success(Task.this.getResult()));
+                } else {
+                    setSignificance(TaskSignificance.MINOR);
+                    setResult(Result.failure(Task.this.getException()));
+                }
+            }
+
+            @Override
+            public Collection<Task<?>> getDependents() {
+                return Collections.singleton(Task.this);
+            }
+
+            @Override
+            public boolean isRelyingOnDependents() {
+                return false;
+            }
+        }.setExecutor(executor).setName(getCaller()).setSignificance(TaskSignificance.MODERATE);
+    }
+
     /**
      * Returns a new Task with the same exception as this task, that executes
      * the given actions when this task completes.

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

@@ -0,0 +1,78 @@
+/*
+ * Hello Minecraft! Launcher
+ * Copyright (C) 2026 huangyuhui <huanghongxun2008@126.com> and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.jackhuang.hmcl.util;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Objects;
+
+/// @author Glavo
+public final class Result<T> {
+    public static <T> Result<T> success(T value) {
+        return new Result<>(value, null);
+    }
+
+    public static <T> Result<T> failure(@NotNull Throwable exception) {
+        Objects.requireNonNull(exception);
+        return new Result<>(null, exception);
+    }
+
+    private final T value;
+    private final Throwable exception;
+
+    private Result(T value, Throwable exception) {
+        this.value = value;
+        this.exception = exception;
+    }
+
+    public boolean isSuccess() {
+        return exception == null;
+    }
+
+    public boolean isFailure() {
+        return exception != null;
+    }
+
+    public T get() throws Throwable {
+        if (exception != null)
+            throw exception;
+        else
+            return value;
+    }
+
+    public @Nullable T getOrNull() {
+        return exception == null ? value : null;
+    }
+
+    public @Nullable Throwable getException() {
+        return exception;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(value, exception);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        return this == obj || obj instanceof Result<?> other
+                && Objects.equals(value, other.value)
+                && Objects.equals(exception, other.exception);
+    }
+}