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https://issues.apache.org/jira/browse/ZOOKEEPER-2369?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15178994#comment-15178994
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Patrick Hunt commented on ZOOKEEPER-2369:
-----------------------------------------
Makes sense. I don't see why we shouldn't do what you suggest (add the flush).
You see why it's a no-op currently though, right? (and why we haven't seen
issues with this code)
> Flushing DataOutputStream before calling toByteArray on the underlying
> ByteArrayOutputStream
> --------------------------------------------------------------------------------------------
>
> Key: ZOOKEEPER-2369
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2369
> Project: ZooKeeper
> Issue Type: Bug
> Reporter: emopers
> Assignee: emopers
> Priority: Minor
>
> In ./src/java/main/org/apache/zookeeper/server/ZooKeeperServer.java
> {code}
> ByteArrayOutputStream baos = new ByteArrayOutputStream();
> BinaryOutputArchive bos = BinaryOutputArchive.getArchive(baos);
> bos.writeInt(-1, "len");
> rsp.serialize(bos, "connect");
> if (!cnxn.isOldClient) {
> bos.writeBool(
> this instanceof ReadOnlyZooKeeperServer, "readOnly");
> }
> baos.close();
> ByteBuffer bb = ByteBuffer.wrap(baos.toByteArray());
> {code}
> BinaryOutputArchive internally uses DataOutputStream as its stream, and 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
> http://stackoverflow.com/questions/2984538/how-to-use-bytearrayoutputstream-and-dataoutputstream-simultaneously-java.
> Moreover, "baos.close()" at second last line is not required as it is no-op
> according to
> [javadoc|http://docs.oracle.com/javase/7/docs/api/java/io/ByteArrayOutputStream.html]
> {quote}
> Closing a ByteArrayOutputStream has no effect. The methods in this class can
> be called after the stream has been closed without generating an IOException.
> {quote}
> The patch is to add flush method on "bos" before calling toByteArray on
> "baos". Similar behavior is also present in the following files:
> ./src/java/main/org/apache/zookeeper/ClientCnxn.java
> ./src/java/main/org/apache/zookeeper/server/ZKDatabase.java
> ./src/java/main/org/apache/zookeeper/server/persistence/Util.java
> ./src/java/main/org/apache/zookeeper/server/NIOServerCnxn.java
> Let me know if this looks good. I can provide patch.
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