What is the method for obtaining the current timestamp in Java?

In Java, you can use the `System.currentTimeMillis()` method to obtain the current timestamp. This method returns the number of milliseconds since January 1, 1970, 00:00:00 GMT.

Here is an example code:

public class Main {
    public static void main(String[] args) {
        long timestamp = System.currentTimeMillis();
        System.out.println("当前时间戳：" + timestamp);
    }
}

The above code utilizes the `System.currentTimeMillis()` method to obtain the current timestamp and prints it to the console. Executing the code will output results similar to the following:

当前时间戳：1629889368558

The timestamp here indicates the number of milliseconds elapsed since January 1st, 1970 at 00:00:00 GMT.