Like Rafal said it's because fedora doesn't come with a lot of the java packages pre-installed. 
Also because yum/dnf is quite different in managing dependencies from most of the modern programming languages (java, python, javascript etc). 

/rant
Modern programming languages allows much finer grain control of those dependencies (e.g. maven for java, pip for python, npm for javascript). You can pick and choose what you want at what version etc. With yum/dnf, if you need package A, and A needs B. Even though you don't require B, it still pulls it for you. To make it worse, a lot of the java library packages bundles multiple jars (the smallest library artifact java build tools uses). This means even if you just need one jar in your actual build, you have to install the whole rpm that comes with more than you need. RPM subpackaging will help but AFAIK a lot of the packagers don't care or won't bother doing that. Not to mention you have no/very little control of what version of the library you are getting from yum... 
/rant

Depends on whether you want less download files or download size.

With dnf in fedora-25:

  Transaction Summary
  Install 103 Packages
  Total download size: 61 M
  Installed size: 149 M

with maven (a popular java build and package manage system)
  zanata-maven-plugin runtime dependencies
  downloaded files: 1358
  downloaded size: 41 M

  Also bear in mind that maven maven does not clean the download cache for package upgrade,
  (and it should not), so in our build server, the download cache directory (~/.m2/repositoy)
  grows to 2.5 G.

And 0install, for 0install and unzip themselves:
  Install 51 Packages
  Total download size: 13 M
  Installed size: 47 M

  And the zanata-cli dist.zip
  Download files: 1
  Download size: 15.3 M


Of course, you can download the zanata-cli dist.zip yourself, the size is 15.3 M

Download wise zanata-python-client is not so terrible, but the support is limited.

So pick the demon you want to tame.


--
Ding-Yi CHEN

Software Engineer, Globalization Group
Red Hat Asia-Pacific Pty Ltd
dchen@redhat.com    
Twitter: @redhatway | Instagram: @redhatinc | Snapchat: @redhatsnaps