Let be declared

int nums [];

i.e. C-like array declartaion. In property type for this field there modify type from int[] to int[][].
You will get

int[][] nums [];


Do it several times -- always add one more dimension -- and then Forte will be adding [] automatically.
Then Forte is locked.

[Update] if the field name is followed by brackets and user adds a dimension to field`s type using property sheet, after reparse the type is given an extra dimension which is displayed back in propert
y sheet. This is confusing and, because reparse occurs after a few seconds after the modification, select whole text in the Type property, so user might accidentaly delete the text.

[Svata] The notation TypeDecl Identifier ArrayDims is allowed by JLS, but currently unsupported by JavaParser.