As per javadoc, StringConcatFactory.makeConcat & makeConcatWithConstants should accept params not more than 200. Whereas long & double occupy 2 slots, expectation when param type is long/double the param count should not exceed 100. Attached code shows that rule is violated. Meaning that StringConcatException is not thrown.

Note: when param type is int, param count exceeding 200 throws exception as expected