javastringdelimiterjava-13

illegal text block open delimiter sequence, missing line terminator


Java 13 is coming, so I started studying its new features, one of which is text blocks.

I wrote a simple program

public final class Example {
    public static void main(String[] args) {
        final String greeting = """Hello
        It's me, Andrew!""";
        System.out.println(greeting);
    }
}

I was expecting to see

Hello
It's me, Andrew!

What I got is a compilation error saying

illegal text block open delimiter sequence, missing line terminator


Solution

  • The context of your text block must start from a new line.

    public final class Example {
        public static void main(String[] args) {
            final String greeting = """
                Hello
                It's me, Andrew!""";
            System.out.println(greeting);
        }
    }
    

    prints

    Hello
    It's me, Andrew!
    

    An excerpt from JEP 355: Text Blocks (Preview):

    A text block consists of zero or more content characters, enclosed by opening and closing delimiters.

    The opening delimiter is a sequence of three double quote characters (""") followed by zero or more white spaces followed by a line terminator. The content begins at the first character after the line terminator of the opening delimiter.

    You don't necessarily have to put a line terminator at the end of your content, though.

    The closing delimiter is a sequence of three double quote characters. The content ends at the last character before the first double quote of the closing delimiter.

    final String greeting = """
        Hello
        It's me, Andrew!
        """;
    

    would mean

    Hello
    It's me, Andrew!
    <an empty line here>
    

    I find it extremely unclear, so I had to share this with the community.