#vulnerable code 
                                public void addSuper(@NotNull Type superclass) {
        this.superclass = superclass;
        table.addSuper(superclass.table);
    } 
                            #location 3 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public void addSuper(@NotNull Type superclass) {
        this.superclass = superclass;
        table.setSuper(superclass.table);
    }