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Commit f48273c1 authored by Michal Senkyr's avatar Michal Senkyr Committed by Wenchen Fan
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[SPARK-18891][SQL] Support for specific Java List subtypes

## What changes were proposed in this pull request?

Add support for specific Java `List` subtypes in deserialization as well as a generic implicit encoder.

All `List` subtypes are supported by using either the size-specifying constructor (one `int` parameter) or the default constructor.

Interfaces/abstract classes use the following implementations:

* `java.util.List`, `java.util.AbstractList` or `java.util.AbstractSequentialList` => `java.util.ArrayList`

## How was this patch tested?

```bash
build/mvn -DskipTests clean package && dev/run-tests
```

Additionally in Spark shell:

```
scala> val jlist = new java.util.LinkedList[Int]; jlist.add(1)
jlist: java.util.LinkedList[Int] = [1]
res0: Boolean = true

scala> Seq(jlist).toDS().map(_.element()).collect()
res1: Array[Int] = Array(1)
```

Author: Michal Senkyr <mike.senkyr@gmail.com>

Closes #18009 from michalsenkyr/dataset-java-lists.
parent 0538f3b0
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