Buildr is a modern build system for Java-based applications including support for Scala, Groovy and a growing number of JVM languages and tools. Buildr combines the expressiveness of the Ruby scripting language with a familiar dependency-based task execution model and project-level structure similar to Apache Maven. This session will introduce Buildr and demonstrate practical solutions to common build problems. Examples will be taken from actual build systems including large-scale Apache projects and frequently-asked questions from the mailing list. In particular, we will demonstrate integration with Apache Ant tasks, handling of multi-lingual projects, and customizations for various source-generation and packaging requirements.