Java

Most of the [Principia] system is written in Java.

Further, the language Principia is deeply influenced by the language Java, as Java encodes many of the current best practises which have paid dramatic dividends. Java is a language in which one can develop and close large systems that work correctly and robustly.

One key example (over and above [strong-typing]) is the [assertive-intention] requirement that overriding methods be declared overridden, by annotation, even though the compiler can infer this information. The dividend pays when refactoring the superclass: deleting the original method will result in warnings appearing at all (supposedly now) overriding methods.

While some see such linguistic features as extra unnecessary work, the reality is dramatically to the contrary.

It is only because of this extra information that development environments can offer time saving features such as [code completion]and [quick fixes], as well as automated validity ensured [refactoring].

In practise, Java writes itself. In particular, most of the "extra baggage" is auto-written, if not immediately, then after a right-click and quick fix.

• Principia aims, by emulating these best practise, to facilitate such environments for the mathematician.