question: private void verifyGridState ( ) { Integer rowLength = null ; int rowPos = 0 ; for ( List < Object > row : grid ) { if ( rowLength != null && rowLength != row . size ( ) ) { throw new IllegalStateException ( "Grid rows do not have the same number of cells, previous: " + rowLength + ", this: " + row . size ( ) + ", at row: " + rowPos ) ; } rowPos ++ ; rowLength = row . size ( ) ; } }
target:  Verifies that all grid rows are of the same length.