TunedIT is a data & algorithm repository, with benchmark results, experiments and online competitions. Datasets in arff, csv, weka formats. Neural networks, svm, decision trees and other algorithms
Jena is a Java framework for building Semantic Web applications. It provides a programmatic environment for RDF, RDFS and OWL, SPARQL and includes a rule-based inference engine.
The OWL API is a Java API and reference implmentation for creating, manipulating and serialising OWL Ontologies. The latest version of the API is focused towards OWL 2