You can't install a java tool-- any java tool-- just by a file copy. At minimum, you need to install the proper version of the JVM (different software may need different versions)-- that's at least 50 MB and maybe 100 these days. Then you need a directory with all the jars which the tool depends on-- figure another 50-100 MB or so for that. Finally, you need a shell script to set up the CLASSPATH, set up any JVM arguments you might need (increased heap size, anyone?) and actually locate the binaries.

In Go, you just copy the binary to the machine and run it.