Multiline String

1. Using Text Blocks (Java 15 and above)

String s = """
           text
           text
           text
           """;

2. Using + Operator

String s = "Some text 1,\n"
         + "Some text 2,\n"
         + "Some text 3,\n"
         + "Some text 4,\n"
         + "Some text 5,\n"
         + "Some text 6";

3. Using StringBuilder

String s = new StringBuilder()
           .append("Some text 1,\n")
           .append("Some text 2,\n")
           .append("Some text 3,\n")
           .append("Some text 5,\n")
           .append("Some text 6,\n")
           .append("Some text 7")
           .toString();

4. Using String.format()

String s = String.format("%s\n%s\n%s\n%s\n%s\n%s"
         , "Some text 1,"
         , "Some text 2,"
         , "Some text 3,"
         , "Some text 4,"
         , "Some text 5,"
         , "Some text 6"
);

5. Using String.join()

// Joining multiple strings
String s = String.join("\n"
         , "Some text 1,"
         , "Some text 2,"
         , "Some text 3,"
         , "Some text 4,"
         , "Some text 5,"
         , "Some text 6"
);

// Joining a list of strings with a comma
List<String> names = List.of("Alice", "Bob", "Charlie");
String result = String.join(", ", names);
System.out.println(result); // Alice, Bob, Charlie

// Joining array elements with a pipe (|)
String[] tokens = {"token1", "token2", "token3"};
String result = String.join(" | ", tokens);
System.out.println(result); // token1 | token2 | token3

6. Using String.concat()

String s= "This is a\n"
           .concat("multiline string\n")
           .concat("using String.concat().");

Comparison

Method	Scenario	Use Case
Text Blocks (Java 15+)	Readability, ease of use, avoiding escape characters	Defining long, static, multiline strings such as SQL queries, HTML content, JSON, or configuration settings. Ideal for one-time definitions.
+ Operator	Simple concatenation, small multiline strings	Quick concatenation in simple cases, such as building a small multiline string inside a method or loop for logging purposes.
StringBuilder	Performance, especially in loops and iterations	Building multiline strings in loops, iterative concatenation where performance is critical. Use for dynamically constructing strings in iterative processes.
String.format()	Formatting with variable substitution	Creating formatted strings with variables, especially when readability is important. Useful for constructing strings with embedded variables.
String.join()	Joining multiple lines from a collection	Joining multiple strings from a collection or array, often used in cases where you have a list of strings that need to be joined with a delimiter.
String.concat()	Chaining method calls, small multiline strings	Simple chaining of strings when constructing small multiline strings in method chains. Suitable for cases where the number of lines is small and readability is not a major concern.