$ ruby -e 'b=-> { Proc.new { return 42 }; }.call; p b; p b.call'
#<Proc:0x00005584560614b0 -e:1>
$ jruby -e 'b=-> { Proc.new { return 42 }; }.call; p b; p b.call'
#<Proc:0xeafc191@-e:1>
Unhandled Java exception: IRReturnJump:<Static Type[1957502751]: block []
Static Type[1780132728]: local [b=#<Proc:0xeafc191@-e:1>]:42>
org.jruby.ir.runtime.IRReturnJump: null