I have a json encoded data below need to be parsed using pig.

{"arr":[1,2,3,4]}

According a document at <http://help.mortardata.com/technologies/pig/json#toc_4JsonLoaderSchemaGuidelines>
, 
my loading schema is:

```
a = load 'testJsonPig.log' using JsonLoader('arr:{t:(i:int)}');

```

and dump it:

```
dump a;

```

but I got an unepected result:

```
()

```

the result is empty, and I don't know why it happened, It seemed that I met a same question as this link
[Pig default JsonLoader schema issue](https://stackoverflow.com/questions/21076583/pig-default-jsonloader-schema-issue?answertab=oldest#tab-top)
 described.

My pig version is 

> 
> Apache Pig version 0.12.1 (r1585011)
> 
> 
> 

and wish someone could help me, thx in advance.