#vulnerable code 
                                public LookbackQuery withInnerQueryPostAggregations(Collection<PostAggregation> postAggregations) {
        return new LookbackQuery(new QueryDataSource(getInnerQuery().withPostAggregations(postAggregations)), granularity, filter, aggregations, getLookbackPostAggregations(), intervals, context, false, lookbackOffsets, lookbackPrefixes, having, limitSpec);
    } 
                            #location 2 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public LookbackQuery withInnerQueryPostAggregations(Collection<PostAggregation> postAggregations) {
        return new LookbackQuery(new QueryDataSource(getInnerQueryUnchecked().withPostAggregations(postAggregations)), granularity, filter, aggregations, getLookbackPostAggregations(), intervals, context, false, lookbackOffsets, lookbackPrefixes, having, limitSpec);
    }