409 response when uploading to artifactory using X-Checksum-Sha1 header with Apache's HTTP client in Java

I am writing a Jenkins plugin in Java that uses the Apache HttpClient (org.apache.http.client.HttpClient) to upload artifacts to JFrog Artifactory. As part of the process I would like to add a checksum to the artifacts that I upload.

From what I understand, this can be done using the X-Checksum headers and calculating the checksum locally. However, when I try to do this, the artifactory server gives me the following response:

{
  "errors" : [ {
    "status" : 409,
    "message" : "Checksum policy 'LocalRepoChecksumPolicy: CLIENT' rejected the
                 artifact 'bluemix-ace-maven-local:test_build/4/log.txt'. Checksums info
                 ChecksumsInfo{
                   checksums={
                     SHA-1=ChecksumInfo{
                       type=SHA-1,
                       original='1a5bc1ae3c47e519f8bd69f90802c9fcf9fbddb3',
                       actual='c4c9da01b9e278d68a4c15bb95e41437799700ed'
                     },
                     MD5=ChecksumInfo{
                       type=MD5,
                       original='null',
                       actual='aa4023acbcb095cceb35ac82f9a913a8'
                     },
                     SHA-256=ChecksumInfo{
                       type=SHA-256,
                       original='null',
                       actual='5032a081754db0ce3f8b394a5215940e30456a77ea1e82765ceb595c8e0050da'
                     }
                   }
                }"
  } ]
}

The checksum I am calculating locally is 1a5bc1ae3c47e519f8bd69f90802c9fcf9fbddb3

I have verified by going into bash and doing a shasum on that file. It matches the above. So for some reason artifactory is calculating a different sha1 sum than the one I have locally. Why might this be?

This issue seems to be very similar:
https://www.jfrog.com/jira/browse/RTFACT-8553

But his solution didn't help me. I have also tried MD5 and SHA256.

I have figured out this problem myself. The problem was that I was using a multipart entity in Java, which means that headers, etc. are added to the uploaded file, which would cause the checksum to be different. I switched to BufferedHttpEntity and now it is working.