Java 21 was packed with exciting and groundbreaking innovations. In the shadow of the very present topics, string templates were relatively surprisingly introduced as a preview feature and are also included again in OpenJDK 22. They allow expressions to be embedded in string literals and text blocks. Thanks to self-definable template processors, this procedure is even customizable.

We discuss the use of string templates, look at the advantages but also the limitations. By creating our own template processors, we can validate and transform the embedded expressions and ultimately create any Java objects such as JSON documents or SQL result sets from Java strings. You can incorporate these ideas into your daily work and try out string interpolation now.