CompletableFuture<List<Location>> (ReferenceType type, String stratum, String sourceName, int lineNumber) { if (type instanceof ReferenceTypeImpl && isAsyncEnabled()) { return reschedule(((ReferenceTypeImpl)type).locationsOfLineAsync(stratum, sourceName, lineNumber)); } return toCompletableFuture(() -> type.locationsOfLine(stratum, sourceName, lineNumber)); }