Here is an example of how to use the ByteQuadsCanonicalizer class from the org.apache.commons.io package in Java to canonicalize a string:

import org.apache.commons.io.ByteQuadsCanonicalizer;

public class Main {
    public static void main(String[] args) {
        String input = "example string to canonicalize";
        ByteQuadsCanonicalizer bqc = new ByteQuadsCanonicalizer();
        String output = bqc.canonicalize(input);
        System.out.println(output);
    }
}

In this example, the input string "example string to canonicalize" is passed to the canonicalize() method of the ByteQuadsCanonicalizer object, which returns the canonicalized version of the string.

Please note that, this class has been removed from apache.commons.io library, it was present in version 2.6, But as of latest version it has been removed, you can use other libraries like Guava library's CharMatcher.java to achieve similar functionality.