The Java Modeling Language (JML) is a behavioral interface specification language that can be used to specify the behavior of Java modules (as in design by contract -- DBC). It has many tools to do assertion checking, unit testing, etc.
The goal of Quality-Check is to provide a small Java library for basic runtime code quality checks. It provides similar features to org.springframework.util.Assert or com.google.common.base.Preconditions without the need to include big libraries or frameworks such as Spring or Guava.
... [More] tries to replace these classes and provide all the basic code quality checks you need. The checks provided here are typically used to validate method parameters and detect errors during runtime. To detect errors before runtime we use JSR-305 Annotations. With these annotations you are able to detect possible bugs earlier. For more informations look at FindBugs™ JSR-305 support. [Less]
Amber is a scripting language inspired by (amongst others) Eiffel and Ruby. It has a concise syntax that's easy to read and maintain.
Amber supports Contract Driven Design (CoDD) for software development, and Contract Hardening (CoHa) for robustness.
Modern Jass is a Design by Contract implementation for Java which uses Java 5 annotations, the Pluggable Annotation Processing API (JSR 269), the Compiler API (JSR 199), and the Bytecode Instrumentation API.