When a collector is used, the distributed streams behave as if the result is "reduced", expecting the collector result to be comparable in size to a cache value.

Most collectors do not reduce the value size at all, e.g. stream.collect(CacheCollectors.serializableCollector(() -> Collectors.toList())), then all the values on a remote node are collected into a single list and marshalled into a single byte array/JGroups message.

The creation of the byte array is likely to fail with an OutOfMemoryError, but if the total size is > 2GB and there is enough free heap memory, an overflow bug in BytesObjectOutput.ensureCapacity() turns the OOME into an ArrayIndexOutOfBoundsException.