What is the usage of ‘await’ in Java?

In Java, await is commonly used to wait for the completion of an asynchronous operation. It is typically used with Future or CompletableFuture to block the current thread until the asynchronous operation is completed and returns a result.

For example, when using CompletableFuture, you can utilize the await method to wait for asynchronous operations to be completed.

CompletableFuture<String> future = CompletableFuture.supplyAsync(() -> {
    // 异步操作
    return "Hello";
});

String result = future.get(); // 阻塞当前线程直到异步操作完成
System.out.println(result);

In this example, using the future.get() method will block the current thread until the asynchronous operation is completed and returns a result. This ensures that the current thread will not proceed with any other logic until the asynchronous operation result is obtained.

It should be noted that the await method is typically used to wait for the results of asynchronous operations and will block the current thread. Therefore, when using it, one should consider the potential issue of thread blocking and avoid causing performance problems in the program.