["appendix",id="painless-api-reference"] = Painless API Reference <> has a strict whitelist for methods and classes to make sure that all painless scripts are secure and fast. Most of these methods are exposed directly from the JRE while others are part of Elasticsearch or Painless itself. Below is a list of all available methods grouped under the classes on which you can call them. Clicking on the method name takes you to the documentation for the method. NOTE: Methods defined in the JRE also have a `(java 9)` link which can be used to see the method's documentation in Java 9 while clicking on the method's name goes to the Java 8 documentation. Usually these aren't different but it is worth going to the version that matches the version of Java you are using to run Elasticsearch just in case. include::painless-api-reference/index.asciidoc[]