This tool generates MD5 and SHA1 digests for an uploaded file and checks to see if the digests are present in the maven repository. This indicates that the uploaded file exists in the maven repository.
MD5 and SHA1 digests are checksums that can be used to uniquely identify a file based on the content of the file, not on the file name. In the maven repository, you can see files ending in .md5 and .sha1, which contain these unique identifiers (represented as hex strings) for a file. Thus, "commons-io-1.3.1.jar" is accompanied by "commons-io-1.3.1.jar.md5" and "commons-io-1.3.1.jar.sha1". Either file (.md5 or .sha1) can be used to uniquely identify "commons-io-1.3.1.jar". If we renamed "commons-io-1.3.1.jar" to be "commons-io.jar" (or "hamburger.jar" or anything else), it would still have the same MD5 and SHA1 digests.
If you have a jar file (typically without a version number on it) and you'd like to see if it exists in the maven repository, you can find this out via the Digest Generator and Checker tool.
If you have an MD5 or SHA1 digest hex string and you'd like to find out if it exists in the maven repository, you can do so by performing a "content" search from the Jarvana main search page. The content search select box can be set to "digest" so that only .md5 and .sha1 files are searched.