Well if you look here:
https://openwrt.org/packages/table/
You can see that package does not exist there either.
You will need to use the GL SDK to compile that classpath package
Follow this thread:
And use this package:
https://github.com/openwrt/packages/tree/master/libs/classpath
You might also have a lot of other dependencies, either available or you need to compile. In the other thread you can see the commands to compile the packages, and how to add dependencies as well.
You can see which are needed in the “DEPENDS:=+alsa-lib +libgmp +libmagic” line of the Makefile for each package.