Does Java have support for multiline strings?

java

prompt-engineering

best-practices

io-operations

byAnton Shumikhin·Feb 5, 2025

Text blocks were introduced in Java 15+ for supporting multiline strings. Here's how to use them:

String text = """
               Line one
               Line two
               Line three""";

Earlier versions have to resort to concatenation or using \n for newlines.

Options for multiline strings before JDK 15

In this section, we'll explore how to handle multiline strings before JDK 15 introduced text blocks.

The classic: string concatenation

Since time immemorial (okay, since JDK 1.0), devs used string concatenation with \n for newlines:

String story = "Once upon a time,\n" +
               "In a land far away,\n" +
               "Every developer dreamt of text blocks.";
// Reality is often disappointing.

The builder: StringBuilder

For performance-oriented coders, StringBuilder.append() has been the trusted ally:

StringBuilder sb = new StringBuilder();
sb.append("Once upon a time,\n");
sb.append("In a land far away,\n");
sb.append("Every developer dreamt of text blocks.");
String story = sb.toString();
// StringBuilder says: I got your back and I won't create unnecessary temp objects!

The formatter: String.format()

Having troubles with readability? String.format() is here for the rescue:

String story = String.format("Once upon a time,%n" +
                             "In a land far away,%n" +
                             "Every developer dreamt of text blocks.");
// String.format says: Readability is my middle name!

The joiner: String.join()

String.join() allows joining strings with a delimiter of your choice:

String story = String.join(System.lineSeparator(),
                           "Once upon a time",
                           "In a land far away",
                           "Every developer dreamt of text blocks.");
// String.join says: I can be your separator today!

The reader: Externally stored strings

For multiline string content that is too large, consider reading it from a text file:

Path path = Paths.get("story.txt");
String story = Files.readString(path);

Remember, dealing with IO operations come with their own set of issues.

The helper: IDE features

Don't forget to use the cool features of your IDE. In Eclipse, "Escape text when pasting into a string literal” saves lot of time.

The previewer: Text blocks in JDK 13/14

You could get a flavor of the future in the past! Good old JDK 13 and 14 let you preview text blocks with a --enable-preview flag. Thank you JEP 378!

Beyond the basic: Advanced techniques

Properties file

Consider using .properties files for storing strings for different locales.

Custom annotations

Thinking of creating custom annotations and an annotation processor for multiline strings? Well, you can. But tread cautiously as it could affect your code maintainability.