جَاءَ قَاضِيَّ — My judge came.
جَاءَ is a past verb.
قَاضِيَّ is the nominative subject and mudāf; its case ending is not overt.
-ي is the attached speaker’s pronoun in the genitive position as mudāf ilayh.
The geminated yāʾ is a morphophonological result, not a visible case vowel.