To match the trademark symbol "™" using regular expressions in Java, you can use the unicode escape sequence "\u2122". Here's an example:

String input = "This is a trademark symbol: \u2122";
if (input.matches(".*\u2122.*")) {
    System.out.println("Input contains a trademark symbol.");
} else {
    System.out.println("Input does not contain a trademark symbol.");
}

In the example above, the "\u2122" unicode escape sequence is used to represent the trademark symbol. The regular expression pattern ".\u2122." matches any string that contains the trademark symbol.

Note that when using regular expressions in Java, the backslash character "" is used to escape special characters. However, in this case we need to use the unicode escape sequence instead of the backslash character to match the trademark symbol.