GORA-467 Flushing DataOutputStream before calling toByteArray on the underlying ByteArrayOutputStream

[emopers]

When a DataOutputStream instance wraps an underlying ByteArrayOutputStream instance,
it is recommended to flush or close the DataOutputStream before invoking the underlying instances's toByteArray(). Also, it is a good practice to call flush/close explicitly as mentioned for example here.
This pull request add a flush method before toByteArray. I have also added a Jira Issue.

[lewismc]

Hi, thanks for the pull request. Are there any other instances of this behavior throughout the codebase? If so it would be real nice to catch them all at the same time.

[lewismc]

Hi @emopers I just undertook a quick scan of the codebase for ByteArrayOutputStream, I found the following instances. Can you please check these out as well?

./gora-accumulo/src/main/java/org/apache/gora/accumulo/encoders/BinaryEncoder.java
./gora-accumulo/src/main/java/org/apache/gora/accumulo/store/AccumuloStore.java
./gora-accumulo/src/main/java/org/apache/gora/accumulo/util/FixedByteArrayOutputStream.java
./gora-accumulo/src/test/java/org/apache/gora/accumulo/store/PartitionTest.java
./gora-cassandra/src/main/java/org/apache/gora/cassandra/serializers/AvroSerializerUtil.java
./gora-core/src/main/java/org/apache/gora/util/AvroUtils.java
./gora-core/src/main/java/org/apache/gora/util/IOUtils.java
./gora-core/src/test/java/org/apache/gora/util/TestWritableUtils.java
./gora-hbase/src/main/java/org/apache/gora/hbase/util/HBaseByteInterface.java

[emopers]

@lewismc Alright, I will look into these and let you know.

[lewismc]

Thanks @emopers

[emopers]

@lewismc I just found two classes out the above you mentioned, which were not following the contract. All other classes looks good.
I have made more commits and squashed them into one. Let me know if can further help.

[lewismc]

@emopers thanks great, I will merge thus patch.
BTW, on another note, I noticed that there a bunch of 'similar' issues present within gora-accumulo's BinaryEncoder, the issues as specifically highlighted by the Sonar Analysis we have running after builds. If you are interested in fixing these issues (marked as critical by Sonar), it would be ideal.