I tested two input files on clowder-dev.

Desert.jpg:
https://opensource.ncsa.illinois.edu/bitbucket/projects/CATS/repos/extractors-versus/browse/test/Desert.jpg

the log of Desert.jpg:

13:54:10,934 DEBUG VersusExtractor:228 - [58b726e34f0c1fe25e0d838e] : Started processing file
13:54:10,935 DEBUG VersusExtractor:228 - [58b726e34f0c1fe25e0d838e] : Downloading file
13:54:10,943 DEBUG VersusExtractor:263 - Content-Typeimage/jpeg
13:54:10,948 DEBUG VersusExtractor:228 - [58b726e34f0c1fe25e0d838e] : Starting Extraction of file descriptors.
13:54:10,951 DEBUG VersusExtractor:311 - adapters list from the Property file: edu.illinois.ncsa.versus.adapter.impl.BufferedImageAdapter
13:54:10,952 DEBUG VersusExtractor:515 - inside create instance
13:54:10,952 DEBUG VersusExtractor:323 - extractors list from the Property file: edu.illinois.ncsa.versus.extract.impl.RGBHistogramExtractor
13:54:10,952 DEBUG VersusExtractor:492 - inside create instance
13:54:10,952 DEBUG VersusExtractor:334 - extractors collection length: 1
13:54:10,952 DEBUG VersusExtractor:335 - adaptors collection length: 1
13:54:10,952 DEBUG VersusExtractor:340 - input file name=medici8002806659474461094.jpeg
13:54:10,952 DEBUG VersusExtractor:341 - input file contentType=image/jpeg
13:54:10,952 DEBUG VersusExtractor:344 - MIME Type of the input file===: image/jpeg

13:54:10,953 DEBUG ExtractionData:99 - Supported Adapters

13:54:10,953 DEBUG ExtractionData:101 - name: Buffered Image
13:54:10,953 DEBUG ExtractionData:123 - *Extractor Name*: edu.illinois.ncsa.versus.extract.impl.RGBHistogramExtractor~_{Extractor Supported Adapter}~:edu.illinois.ncsa.versus.adapter.impl.BufferedImageAdapter
13:54:10,953 DEBUG ExtractionData:127 - ---INPUT SUPPORTED ADAPTER NAME:-edu.illinois.ncsa.versus.adapter.impl.BufferedImageAdapter
13:54:10,953 DEBUG ExtractionData:132 - Number of Interfaces Implemented by the Input supported Adapter : 3
13:54:10,953 DEBUG ExtractionData:140 - ++ADAPTER MATCH+++ sa.getClass().getName()=edu.illinois.ncsa.versus.adapter.impl.BufferedImageAdapter name=edu.illinois.ncsa.versus.adapter.impl.BufferedImageAdapter x.getName()=java.io.Serializable
13:54:10,954 DEBUG ExtractionData:152 -
13:54:10,954 DEBUG VersusExtractor:354 -
13:54:10,954 DEBUG VersusExtractor:355 - *Creation of Local Job*
13:54:10,954 DEBUG VersusExtractor:228 - [58b726e34f0c1fe25e0d838e] : creating a local job for the extraction
13:54:10,954 DEBUG VersusExtractor:537 - Exdata Status: STARTED
13:54:10,955 DEBUG ExtractionEngine:105 - Inside extractSignature
13:54:10,955 DEBUG VersusExtractor:578 - Exdata Status: PROCESSING
13:54:10,955 DEBUG VersusExtractor:549 - Extraction started
13:54:10,955 DEBUG ExtractionCallable:62 - Thread Executing:pool-6-thread-1
13:54:10,955 DEBUG VersusExtractor:228 - [58b726e34f0c1fe25e0d838e] : Checking the status of the extraction of file descriptors.
13:54:10,955 DEBUG ExtractionCallable:70 - Unsupported Type Exception
13:54:10,956 DEBUG ExtractionCallable:72 - Descriptor created for file /tmp/medici8002806659474461094.jpeg
13:54:10,956 DEBUG VersusExtractor:545 - Exdata Status: DONE
13:54:10,966 DEBUG VersusExtractor:228 - [58b726e34f0c1fe25e0d838e] : Getting the extracted file descriptors.
[postMetaDataJsonLD]: http://bd-clowder-dev.ncsa.illinois.edu:9000/clowder-dev/api/files/58b726e34f0c1fe25e0d838e/metadata.jsonld?key=r1ek3rs
13:54:10,976 DEBUG VersusExtractor:228 - [58b726e34f0c1fe25e0d838e] : DONE.

and ncsa.jpg:
http://browndog.ncsa.illinois.edu/examples/ncsa.jpg

There is empty versus content for Desert.jpg:
http://bd-clowder-dev.ncsa.illinois.edu:9000/clowder-dev/files/58b726e34f0c1fe25e0d838e

There is correct versus content:
http://bd-clowder-dev.ncsa.illinois.edu:9000/clowder-dev/files/58b727084f0c1fe25e0d83de

the log of ncsa.jpg

13:54:47,401 DEBUG VersusExtractor:228 - [58b727084f0c1fe25e0d83de] : Started processing file
13:54:47,405 DEBUG VersusExtractor:228 - [58b727084f0c1fe25e0d83de] : Downloading file
13:54:47,412 DEBUG VersusExtractor:263 - Content-Typeimage/jpeg
13:54:47,473 DEBUG VersusExtractor:228 - [58b727084f0c1fe25e0d83de] : Starting Extraction of file descriptors.
13:54:47,477 DEBUG VersusExtractor:311 - adapters list from the Property file: edu.illinois.ncsa.versus.adapter.impl.BufferedImageAdapter
13:54:47,477 DEBUG VersusExtractor:515 - inside create instance
13:54:47,477 DEBUG VersusExtractor:323 - extractors list from the Property file: edu.illinois.ncsa.versus.extract.impl.RGBHistogramExtractor
13:54:47,477 DEBUG VersusExtractor:492 - inside create instance
13:54:47,477 DEBUG VersusExtractor:334 - extractors collection length: 1
13:54:47,477 DEBUG VersusExtractor:335 - adaptors collection length: 1
13:54:47,477 DEBUG VersusExtractor:340 - input file name=medici5974163744625962968.jpeg
13:54:47,478 DEBUG VersusExtractor:341 - input file contentType=image/jpeg
13:54:47,478 DEBUG VersusExtractor:344 - MIME Type of the input file===: image/jpeg

13:54:47,478 DEBUG ExtractionData:99 - Supported Adapters

13:54:47,478 DEBUG ExtractionData:101 - name: Buffered Image
13:54:47,478 DEBUG ExtractionData:123 - *Extractor Name*: edu.illinois.ncsa.versus.extract.impl.RGBHistogramExtractor~_{Extractor Supported Adapter}~:edu.illinois.ncsa.versus.adapter.impl.BufferedImageAdapter
13:54:47,478 DEBUG ExtractionData:127 - ---INPUT SUPPORTED ADAPTER NAME:-edu.illinois.ncsa.versus.adapter.impl.BufferedImageAdapter
13:54:47,478 DEBUG ExtractionData:132 - Number of Interfaces Implemented by the Input supported Adapter : 3
13:54:47,478 DEBUG ExtractionData:140 - ++ADAPTER MATCH+++ sa.getClass().getName()=edu.illinois.ncsa.versus.adapter.impl.BufferedImageAdapter name=edu.illinois.ncsa.versus.adapter.impl.BufferedImageAdapter x.getName()=java.io.Serializable
13:54:47,478 DEBUG ExtractionData:152 -
13:54:47,478 DEBUG VersusExtractor:354 -
13:54:47,478 DEBUG VersusExtractor:355 - *Creation of Local Job*
13:54:47,478 DEBUG VersusExtractor:228 - [58b727084f0c1fe25e0d83de] : creating a local job for the extraction
13:54:47,479 DEBUG VersusExtractor:537 - Exdata Status: STARTED
13:54:47,479 DEBUG ExtractionEngine:105 - Inside extractSignature
13:54:47,479 DEBUG VersusExtractor:578 - Exdata Status: PROCESSING
13:54:47,479 DEBUG VersusExtractor:549 - Extraction started
13:54:47,479 DEBUG VersusExtractor:228 - [58b727084f0c1fe25e0d83de] : Checking the status of the extraction of file descriptors.
13:54:47,479 DEBUG ExtractionCallable:62 - Thread Executing:pool-7-thread-1
13:54:47,954 DEBUG ExtractionCallable:72 - Descriptor created for file /tmp/medici5974163744625962968.jpeg
13:54:47,954 DEBUG VersusExtractor:545 - Exdata Status: DONE
13:54:47,957 DEBUG VersusExtractor:228 - [58b727084f0c1fe25e0d83de] : Getting the extracted file descriptors.
13:54:47,958 DEBUG VersusExtractor:420 - Adapter Name :-edu.illinois.ncsa.versus.adapter.impl.BufferedImageAdapter Extractor:-edu.illinois.ncsa.versus.extract.impl.RGBHistogramExtractor bytes array size:=234
[postMetaData]: http://bd-clowder-dev.ncsa.illinois.edu:9000/clowder-dev/api/files/58b727084f0c1fe25e0d83de/versus_metadata?key=r1ek3rs
[postMetaDataJsonLD]: http://bd-clowder-dev.ncsa.illinois.edu:9000/clowder-dev/api/files/58b727084f0c1fe25e0d83de/metadata.jsonld?key=r1ek3rs
13:54:47,987 DEBUG VersusExtractor:228 - [58b727084f0c1fe25e0d83de] : DONE.