Characters like ``++'é'++`` can be expressed either as a single code point or as a cluster of the letter ``++'e'++`` and a combining accent mark. Without the ``++CANON_EQ++`` flag, a regex will only match a string in which the characters are expressed in the same way. == Noncompliant Code Example ---- String s = "e\u0300"; Pattern p = Pattern.compile("é|ë|è"); // Noncompliant System.out.println(p.matcher(s).replaceAll("e")); // print 'é' ---- == Compliant Solution ---- String s = "e\u0300"; Pattern p = Pattern.compile("é|ë|è", Pattern.CANON_EQ); System.out.println(p.matcher(s).replaceAll("e")); // print 'e' ----