Working with Multiline Strings in Java using Text Blocks (Java 13+)

📘 Introduction

Dealing with multiline strings in Java has always been a bit cumbersome—developers had to concatenate strings using +, escape line breaks, or use external files. This made code messy, harder to read, and prone to errors.

Java 13 introduced Text Blocks as a preview feature, which became a permanent feature in Java 15. Text blocks provide a clean, concise, and readable way to declare multiline strings without boilerplate. They significantly improve readability and reduce the chances of bugs in string-heavy code.

In this tutorial, we’ll explore how to use text blocks effectively with real-world examples, version notes, and best practices.

🔍 What is a Text Block?

A text block is a multiline string literal that begins and ends with triple double-quote (""") and preserves the content between them, including new lines and indentation.

✅ Syntax

String json = """
    {
      "name": "Java",
      "version": 21
    }
    """;

No need for escape characters or + operators!

🧠 Purpose and Benefits

✅ Clean multiline string support
✅ No need for escaping double quotes or line breaks
✅ Preserves structure and formatting (great for HTML, JSON, SQL)
✅ Easy to edit and visualize

🔧 Example Use Cases

Embedding JSON/XML in code
Writing SQL queries inside DAOs
Constructing HTML templates for emails
Creating Markdown or documentation templates

📦 Example – SQL Query

String query = """
    SELECT *
    FROM users
    WHERE status = 'ACTIVE'
    ORDER BY created_at DESC;
    """;

📦 Example – HTML Template

String html = """
    <html>
      <body>
        <h1>Hello, World!</h1>
      </body>
    </html>
    """;

⚙️ Behavior and Formatting Rules

Leading whitespace is trimmed based on the least-indented line
\ at the end of a line escapes the newline (useful for line continuation)
You can embed " without escaping

String quote = """
    He said, "Text blocks are awesome!"
    """;

📊 Java Version Support

Java Version	Text Blocks Support
Java 13	Preview feature (must enable with `--enable-preview`)
Java 14	Preview feature
Java 15+	Officially available and stable

🚀 Refactoring Example

Before (pre-Java 13):

String sql = "SELECT * FROM users\n" +
             "WHERE status = 'ACTIVE'\n" +
             "ORDER BY created_at DESC;";

After (Java 15+):

String sql = """
    SELECT * FROM users
    WHERE status = 'ACTIVE'
    ORDER BY created_at DESC;
    """;

⚖️ Pros and Cons

✅ Pros

Great readability and maintainability
Native support for HTML/JSON/SQL formats
No need for \n or escaping quotes

❌ Cons

Available only from Java 13+ (standard from 15)
Slight learning curve around indentation handling

📌 What's New in Java Versions?

✅ Java 13: Introduced text blocks as preview feature
✅ Java 14: Refined indentation and escaping
✅ Java 15: Text blocks became permanent
✅ Java 21: Works seamlessly with String templates (preview)

🧨 Edge Cases and Gotchas

Watch out for inconsistent indentation — Java uses the least-indented line to determine baseline
Trailing whitespaces are preserved
You can escape a newline using \ if needed for line continuation

String code = """
    public void hello() { \
        System.out.println("Hello");
    }
    """;

🧹 Best Practices

Use for any long-form string with structure (SQL, HTML, JSON, Markdown)
Avoid mixing tabs and spaces
Use consistent indentation
Don’t use for short single-line strings unless you're planning to expand

📋 Conclusion and Key Takeaways

Text blocks are a powerful and long-overdue addition to the Java language. They significantly improve the readability and maintainability of code that deals with multiline strings, especially in templating-heavy domains like web development or database operations.

By upgrading to Java 15+, you can take full advantage of this cleaner syntax and write more expressive code.

❓ FAQ: Frequently Asked Questions

Are text blocks available in Java 8 or 11?
No, text blocks were introduced as a preview in Java 13 and made stable in Java 15.
Do I need to escape double quotes inside text blocks?
No, you can use " directly inside a text block without escaping.
How do line breaks work in text blocks?
They are preserved automatically. You can use \ to escape a line break.
What’s the difference between \n and real newlines in text blocks?
Text blocks preserve actual newlines; \n is just a character sequence.
Is it okay to indent text blocks inside methods or classes?
Yes, Java adjusts based on the least-indented line within the block.
Can I use text blocks in annotations or constants?
Yes, but the Java version must be 15 or above.
Can I use text blocks with formatted strings?
Yes, use String.format() or Java 21’s string templates for that.
Can I disable trailing whitespace trimming?
No, but you can control whitespace by managing your block content and indentation carefully.
Do IDEs support text blocks well?
Most modern IDEs (IntelliJ, Eclipse, VS Code) support them fully from Java 15 onward.
Will text blocks increase memory usage?
No, they’re compiled just like regular string literals.