haha.Task$Main.main(String[]) explicitly invokes run on a thread (did you mean to start it instead?)

这句话是Java中在执行多线程程序时可能出现的一个警告信息。在Java中，创建和执行线程通常有几种方式，最常见的是通过继承Thread类或者实现Runnable接口。当你在程序中创建了一个Thread的实例，并直接调用它的run方法时，这个警告就会出现。

警告的含义是，你可能误解了run方法的用途。在Java中，run方法是线程任务的具体实现，而start方法是用来启动一个新线程的。当你调用start方法时，它会在线程的上下文中创建一个新的线程，并在这个新线程中调用run方法。如果直接调用run方法，它则会在当前线程中同步执行，而不会创建新的线程。

因此，如果你想让一个任务在新的线程中异步执行，你应该调用start方法，而不是run方法。下面是一个简单的示例：

class MyThread extends Thread {
    public void run() {
        // 线程任务代码
    }
}

public class Main {
    public static void main(String[] args) {
        MyThread t = new MyThread();
        // 应该调用start而不是run
        t.start(); // 正确的启动线程方式
        // t.run(); // 这样做会触发警告，并在当前线程中同步执行run方法
    }
}

相关问题

module 'tensorflow' has no attribute 'Session'. Did you mean: 'version'?

This error message is indicating that you are trying to use the `Session` attribute in TensorFlow, but it is not available in the version you are using. Starting from TensorFlow 2.0, the eager execution mode is enabled by default, which means that you don't need to use sessions explicitly anymore.

If you are following an old tutorial or code example that uses sessions, you can try to modify it to work with TensorFlow 2.0+ by removing the session-related code and using the eager execution mode instead.

If you still need to use sessions in your code, you can try to downgrade your TensorFlow version to a version that supports sessions, such as TensorFlow 1.x. However, it is recommended to migrate your code to use the new TensorFlow API instead of relying on sessions.

Can not deserialize instance of scala.collection.immutable.List$ out of START_ARRAY token

This error message typically occurs when you are trying to deserialize a JSON array into a Scala List using a library such as Jackson or Gson. The error message is telling you that the library is expecting a JSON object but instead, it is receiving a JSON array.

To fix this issue, you need to ensure that the JSON data is in the correct format for deserialization. If you are using Jackson, you can annotate the field or constructor parameter with @JsonDeserialize(as = List.class) to explicitly tell the library to deserialize the JSON array into a List. If you are using Gson, you can use the TypeToken class to specify the type of the object you want to deserialize.

Another possible solution is to modify the JSON data to match the expected format for deserialization. For example, if you have an array of objects, you can wrap it in a JSON object with a key that represents the name of the array. This will allow you to deserialize the JSON data into a map, where the key maps to a List of objects.