X10 CM17A API
an API to control the FireCracker Computer Interface (CM17A) from any computer with a serial port
X4J Analytic is a reporting API for Java. The implementation focuses on Excel reporting and delivers a high performance solution for huge reports.
XOM is an XML object model. It is a tree-based API for processing XML with Java that simultaneously supports streaming. In many use-cases, it can process arbitrarily large documents with effectively constant memory sizes. It strives for correctness, simplicity, and performance, in that order. XOM supports XSLT, Canonical XML, and XInclude.
an extensible object-relational mapping layer for Java applications. It provides interface-based persistence to RDBMSs while allowing developers to focus on the object model, not the physical layer
a Java API for XPointer. XPointer is a W3C standard for addressing into the internal structure of XML documents
XT is a fast, free implementation of XSLT in java.