To match any character in the Greek extended or Greek script using regular expressions in Java, you can use the Unicode character ranges for these scripts in your regular expression pattern.

The Unicode character range for the Greek script is \p{InGreek}, and the Unicode character range for the Greek extended script is \p{InGreekExtended}. To match any character in both scripts, you can combine these ranges using a pipe symbol |.

Here's an example of a regular expression pattern that matches any character in the Greek extended or Greek script:

String pattern = "[\\p{InGreek}\\p{InGreekExtended}]";

In this pattern, the square brackets define a character class that matches any character within the specified ranges. The \\p notation is used to indicate the Unicode character range.

You can use this regular expression pattern to match input strings that contain characters in the Greek extended or Greek script:

String input = "Ελληνικό κείμενο στην Ελλάδα";

String pattern = "[\\p{InGreek}\\p{InGreekExtended}]";
Pattern regex = Pattern.compile(pattern);
Matcher matcher = regex.matcher(input);

while (matcher.find()) {
    String match = matcher.group();
    System.out.println("Found match: " + match);
}

In this example, the input string contains several characters in the Greek extended and Greek script, so the while loop will iterate over each match and print it to the console.

Using regular expressions to match characters in the Greek extended or Greek script can be a useful technique when you need to process text in Greek language. However, keep in mind that regular expressions can be complex and difficult to read and maintain, so it's important to use them judiciously and test them thoroughly to ensure that they work as expected.