Yes, it is possible to access the Java API available in JDK 8. The standard Java API is available on Tropo. For more information on accessing the Java API from your scripting language please refer to:
Groovy: It's built-in. Just write the Java code right in your Groovy.
PHP: Working with Java classes in PHP
Python: Interaction with Java Packages
Ruby: Scripting Java from JRuby