[SPARK-20143][SQL] DataType.fromJson should throw an exception with better message

## What changes were proposed in this pull request?

Currently, `DataType.fromJson` throws `scala.MatchError` or `java.util.NoSuchElementException` in some cases when the JSON input is invalid as below:

```scala
DataType.fromJson(""""abcd"""")
```

```
java.util.NoSuchElementException: key not found: abcd
  at ...
```

```scala
DataType.fromJson("""{"abcd":"a"}""")
```

```
scala.MatchError: JObject(List((abcd,JString(a)))) (of class org.json4s.JsonAST$JObject)
  at ...
```

```scala
DataType.fromJson("""{"fields": [{"a":123}], "type": "struct"}""")
```

```
scala.MatchError: JObject(List((a,JInt(123)))) (of class org.json4s.JsonAST$JObject)
  at ...
```

After this PR,

```scala
DataType.fromJson(""""abcd"""")
```

```
java.lang.IllegalArgumentException: Failed to convert the JSON string 'abcd' to a data type.
  at ...
```

```scala
DataType.fromJson("""{"abcd":"a"}""")
```

```
java.lang.IllegalArgumentException: Failed to convert the JSON string '{"abcd":"a"}' to a data type.
  at ...
```

```scala
DataType.fromJson("""{"fields": [{"a":123}], "type": "struct"}""")
  at ...
```

```
java.lang.IllegalArgumentException: Failed to convert the JSON string '{"a":123}' to a field.
```

## How was this patch tested?

Unit test added in `DataTypeSuite`.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #17468 from HyukjinKwon/fromjson_exception.

0 files changed, 0 insertions, 0 deletions