== Why is this an issue?

include::../description.adoc[]


=== Noncompliant code example

[source,java]
----
static final Pattern p = Pattern.compile("^$", Pattern.MULTILINE); // Noncompliant

// Alternatively
static final Pattern p = Pattern.compile("(?m)^$"); // Noncompliant


boolean containsEmptyLines(String str) {
    return p.matcher(str).find();
}

// ...
System.out.println(containsEmptyLines("a\n\nb")); // correctly prints 'true'
System.out.println(containsEmptyLines("")); // incorrectly prints 'false'
----



=== Compliant solution

[source,java]
----
static final Pattern p = Pattern.compile("^$", Pattern.MULTILINE);

boolean containsEmptyLines(String str) {
    return p.matcher(str).find() || str.isEmpty();
}

// ...
System.out.println(containsEmptyLines("a\n\nb")); // correctly prints 'true'
System.out.println(containsEmptyLines("")); // also correctly prints 'true'
----



include::../implementation.adoc[]