question: public void required ( int table , int field ) { int table_start = bb . capacity ( ) - table ; int vtable_start = table_start - bb . getInt ( table_start ) ; boolean ok = bb . getShort ( vtable_start + field ) != 0 ; if ( ! ok ) throw new AssertionError ( "FlatBuffers: field " + field + " must be set" ) ; }
target:  Checks that a required field has been set in a given table that has just been constructed.