Well, Java compiles to bytecode. The bytecode gets interpreted at runtime by the JVM. In this context, the line between a compiler and an interpreter is fuzzy.
I guess the developer who wrote the challenge just wanted to find someone who is capable of developing and maintaining a language, written in java, to design 3d shapes for their 3d printer.
I know what the developer probably means, but I think he should be more clear and answer a few questions before somebody commits a weekend to work on his task.
Company : Pirate 3D, a Kickstarter funded 3D printing company.
Howto : Pass the small challenge. We flight you to Singapore asap if we like what you do.
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Main task : Creation of a webstore in Ember.js or AngularJS.
Details : http://pirate3d.com/challenges/#web1
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Main task : Creation of a language compiler and related, in Java.
Details : http://pirate3d.com/challenges/#java1
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(keyword) H1B : We can get you a work visa within a few days (processing is usually very fast).