Is there a difference between the UTC and Etc/UTC time zones?

Question

In the PHP documentation, list of supported time zones, UTC is listed twice:

• UTC
• Etc/UTC

Is there an

Answer 1

ETC/GMT+4 is the same as GMT-4.

public static void main(String[] args) {
    TimeZone tz = TimeZone.getTimeZone("Etc/GMT-7");
    System.out.println(tz);

    tz = TimeZone.getTimeZone("GMT+7");
    System.out.println(tz);

}

You can test it by yourself.

But I don't know what ETC mean..