## Why is this an issue?

When an alternation contains multiple alternatives that consist of a single character, it can be rewritten as a character class. This should be preferred because it is more efficient and can even help prevent stack overflows when used inside a repetition (see rule {rule:java:S5998}).

### Noncompliant code example

    Pattern.compile("a|b|c"); // Noncompliant

### Compliant solution

    Pattern.compile("[abc]");
    // or
    Pattern.compile("[a-c]");