Going from Javanese to Kurdish (Kurdî) has a composite linguistic distance of 84% (heuristic estimate). Below is the dimension-by-dimension breakdown.
Shared vocabulary, cognates, and loanwords.
Morphology, syntax, word order, cases.
Shared sounds and phoneme inventory.
Latin/Javanese → Latin/Arabic
Austronesian ↔ Indo-European
The 5 languages with the lowest linguistic distance from Javanese:
A quick 3-question check between Javanese and Kurdish. No signup.