bazaarvoice/jolt: JSON to JSON transformation library written in Java.

bazaarvoice/jolt: JSON to JSON transformation library written in Java.

The primary goal of Jolt was to improve "developer speed" by providing the ability to have a declarative rather than imperative transforms. That said, Jolt should have a better runtime than the alternatives listed above.

Work has been done to make the stock Jolt transforms fast:

1. Transforms can be initialized once with their spec, and re-used many times in a multi-threaded environment.
   • We reuse initialized Jolt transforms to service multiple web requests from a DropWizard service.
2. "*" wildcard logic was redone to reduce the use of Regex in the common case, which was a dramatic speed improvement.
3. The parallel tree walk performed by Shiftr was optimized.

Two things to be aware of :

1. Jolt is not "stream" based, so if you have a very large Json document to transform you need to have enough memory to hold it.
2. The transform process will create and discard a lot of objects, so the garbage collector will have work to do.

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