[[breaking_60_java_changes]]
=== Java API changes

==== `setSource` methods require XContentType

Previously the `setSource` methods and other methods that accepted byte/string representations of
an object source did not require the XContentType to be specified. The auto-detection of the content
type is no longer used, so these methods now require the XContentType as an additional argument when
providing the source in bytes or as a string.

==== `DeleteByQueryRequest` requires an explicitly set query

In previous versions of Elasticsearch, delete by query requests without an explicit query
were accepted, match_all was used as the default query and all documents were deleted
as a result. From version 6.0.0, a `DeleteByQueryRequest` requires an explicit query be set.

==== `InternalStats` and `Stats` getCountAsString() method removed

The `count` value in the stats aggregation represents a doc count that shouldn't require a formatted
version. This method was deprecated in 5.4 in favour of just using
`String.valueOf(getCount())` if needed

==== `ActionRequestBuilder#execute` returns `ActionFuture` rather than `ListenableActionFuture`

When sending a request through the request builders e.g. client.prepareSearch().execute(), it used to
be possible to call `addListener` against the returned `ListenableActionFuture`. With this change an
`ActionFuture` is returned instead, which is consistent with what the `Client` methods return, hence
it is not possible to associate the future with listeners. The `execute` method that accept a listener
as an argument can be used instead.

==== `Terms.Order` and `Histogram.Order` classes replace by `BucketOrder`

The `terms`, `histogram`, and `date_histogram` aggregation code has been refactored to use common
code for ordering buckets. The `BucketOrder` class must be used instead of `Terms.Order` and
`Histogram.Order`. The `static` methods in the `BucketOrder` class must be called instead of directly
accessing internal order instances, e.g. `BucketOrder.count(boolean)` and `BucketOrder.aggregation(String, boolean)`.
Use `BucketOrder.key(boolean)` to order the `terms` aggregation buckets by `_term`.