Thank you very much,
I just realized after reading your code that I'm actually printing hits, not aggregations. There wasn't any problem with my code 
I'm glad I found it before someone else so I can be less embarrassed.
To print the aggregations above you can use this Its raw but usable:
Histogram agg = searchResponse.getAggregations().get("date_aggregation");
// For each entry
for (Histogram.Bucket entry : agg.getBuckets()) {
Min min_agg = entry.getAggregations().get("minValue");
Max max_agg = entry.getAggregations().get("maxValue");
Avg avg_agg = entry.getAggregations().get("avgValue");
Sum sum_agg = entry.getAggregations().get("totalValue");
System.out.println("minValue: " +min_agg.getValue()+" maxValue: " +max_agg.getValue()+" avgValue: " +avg_agg.getValue()+" totalValue: " +sum_agg.getValue());
}