The Solaris manpage for vfork() says:

The vfork() and vforkx() functions are deprecated. Their sole legiti-
mate use as a prelude to an immediate call to a function from the exec
family can be achieved safely by posix_spawn(3C) or posix_spawnp(3C).

and use of vfork() generates compilation warnings:

warning: "vfork" is deprecated, declared in : "/usr/include/unistd.h", line 535

and when Java is built with warnings-as-errors (the default), the build fails as a result.

Code that uses vfork() on Solaris should therefore be removed.