To match any currency symbol using regular expressions in Java, you can use the Unicode character range for currency symbols in your regular expression pattern. The Unicode character range for currency symbols is \p{Sc}.

Here's an example of a regular expression pattern that matches any currency symbol:

String pattern = "\\p{Sc}";

In this pattern, the backslash \ is used to escape the p and S characters, which together indicate the Unicode currency symbol range.

You can use this regular expression pattern to match input strings that contain currency symbols:

String input = "The price is $25.00";
String pattern = "\\p{Sc}";

Pattern regex = Pattern.compile(pattern);
Matcher matcher = regex.matcher(input);

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

In this example, the input string contains the currency symbol $, so the while loop will iterate over each match and print it to the console.

You can modify the regular expression pattern to match specific currency symbols or combinations of symbols as needed. For example, to match the euro symbol specifically, you could use the following pattern:

String pattern = "€";

In this pattern, the euro symbol is enclosed in quotes to indicate a literal match.

Using regular expressions to match currency symbols in Java can be a useful technique when you need to extract or validate currency values in text data. 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.