Contracts for Java (Cofoja) adds contract programming support to Java through simple yet powerful annotations: @Requires, @Ensures, @Invariant, and @ThrowEnsures. Contracts are inherited from interfaces and superclasses and can be enabled selectively during development then disabled for release.
GRAL is a library for creating high quality plots and charts in Java. Many plot types are available like scatter plot, bubble plots, line plots, area plots, pie charts, and bar charts. Additionally, GRAL can exchange and process data (smoothing), and various plug-ins allow the import and export of data and graphics to formats like CSV, JPEG, PNG, EPS, PDF, or SVG.