# Answer from Java side is empty

**URL:** <https://discuss.hail.is/t/answer-from-java-side-is-empty/2040>\
**Category:** Hail Query & hailctl\
**Created:** [May 9, 2021, 8:27pm UTC](https://discuss.hail.is/t/answer-from-java-side-is-empty/2040 "2021-05-09T20:27:09Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![DAU](https://avatars.discourse-cdn.com/v4/letter/d/aeb1de/32.png) [@DAU](https://discuss.hail.is/u/DAU)\
**Post date:** [May 9, 2021, 8:27pm UTC](https://discuss.hail.is/t/answer-from-java-side-is-empty/2040/1 "2021-05-09T20:27:09Z")

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I caught such error when I tried to write gwas results:

gwas.write(‘ldlp.ht’)

Hail version is 0.2.65-367cf1874d85

I used:

use OpenBLAS  
use .openblas\_for\_hail-0.2.20  
export LD\_PRELOAD=/broad/software/free/Linux/redhat\_7\_x86\_64/pkgs/openblas\_0.2.20/lib/libopenblas.so  
but It does not help  
I am working on Broad cluster and when I run it in jupyter based on Anaconda3 all works well

Exception happened during processing of request from (‘127.0.0.1’, 44310)  
ERROR:root:Exception while sending command.  
Traceback (most recent call last):  
File “/humgen/atgu1/methods/dusoltsev/programms/hail\_3\_8/lib/python3.8/site-packages/py4j/java\_gateway.py”, line 1207, in send\_command  
raise Py4JNetworkError(“Answer from Java side is empty”)  
py4j.protocol.Py4JNetworkError: Answer from Java side is empty

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**Author:** ![tpoterba](https://yyz2.discourse-cdn.com/flex036/user_avatar/discuss.hail.is/tpoterba/32/61_2.png) [@tpoterba](https://discuss.hail.is/u/tpoterba)\
**Post date:** [May 10, 2021, 12:09pm UTC](https://discuss.hail.is/t/answer-from-java-side-is-empty/2040/2 "2021-05-10T12:09:52Z")

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This looks like the JVM is running out of memory. Can you try setting the PYSPARK\_SUBMIT\_ARGS env var as in [BGEN filter\_cols memory leak](https://discuss.hail.is/t/bgen-filter-cols-memory-leak/2025)?

> [@BGEN filter\_cols memory leak](https://discuss.hail.is/t/bgen-filter-cols-memory-leak/2025/1):
>
> export PYSPARK\_SUBMIT\_ARGS=“–driver-memory 8G pyspark-shell --executor-memory 8G” ## and with 4G as well. Without this line, I run out of memory a la “java.lang.OutOfMemoryError: Java heap space, in Stage 2.”