In Java 15 Text Blocks are now official and can be used. The most common pattern for multiline strings in Java < 15 was to write String concatenation. Now it's possible to do it in a more natural way using Text Blocks.
String textBlock = "<html>\n" + " <body>\n" + " <tag>\n" + " </tag>\n" + " </body>\n" + "</html>";
String textBlock = """ <html> <body> <tag> </tag> </body> </html>""";