GitHub user krishna-pandey opened a pull request:
https://github.com/apache/zeppelin/pull/2564
[ZEPPELIN-2896] Replacing addHeader with setHeader method in CorsFilter.java
### What is this PR for?
HTTP Response Headers were being added multiple times. Replacing addHeader
method with setHeader overrides the Response Header value with new/existing
value instead of adding another duplicate response Header.
### What type of PR is it?
[Bug Fix]
### What is the Jira issue?
* https://issues.apache.org/jira/browse/ZEPPELIN-2896
### How should this be tested?
Open the Zeppelin URL in Chrome Browser. Select "More Tools" -> "Developer
Tools" from the right-side menu. Under Network Section, select the request with
name "localhost" and check for "Response Headers". You should see response
headers appearing only once.

You can merge this pull request into a Git repository by running:
$ git pull https://github.com/krishna-pandey/zeppelin ZEPPELIN-2896
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/zeppelin/pull/2564.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #2564
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commit 89a3fdcd3994070f872ca755587a0f10f76c6917
Author: krishna-pandey <[email protected]>
Date: 2017-09-04T09:39:59Z
replacing addHeader with setHeader
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