tisonkun opened a new issue, #468:
URL: https://github.com/apache/arrow-java/issues/468

   ### Describe the usage question you have. Please include as many useful 
details as possible.
   
   
   Now I have a `VectorSchemaRoot`. I can see to iterate over the batch with 
`getVector` and then `getObject`.
   
   But the return value is of type `Obejct`. And I wonder how I can downcast it 
for some useful class I can retrieve the real value (string, int, float, etc.).
   
   I know we have the field info of each vetcor, but I don't know the mapping 
between field type to real Java class. It looks over challenge to remember all 
the mapping by reverse engineering the code, and it may change as version 
evolves.
   
   I checked https://arrow.apache.org/docs/java/index.html but all the pages 
tell about constructing a batch and how to move it from one place to another, 
rather than tell about how to read and dump a batch to a typed two-dimensional 
matrix.
   
   The most trivial usage, `contentToTSVString`, call `Object::toString` on 
each cell. But I don't thing we should convert all the values to String and 
reparse it to concrete type.


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