Reason behind some targets as OBJECT, and some as STATIC in cmake

[karthikeyann]

Some of the objects are declared as OBJECT in Cmake.
for Example, all connectors are listed as OBJECT.

./velox/experimental/wave/exec/CMakeLists.txt:21:  OBJECT
./velox/connectors/tpch/CMakeLists.txt:15:velox_add_library(velox_tpch_connector OBJECT TpchConnector.cpp)
./velox/connectors/hive/CMakeLists.txt:15:velox_add_library(velox_hive_config OBJECT HiveConfig.cpp)
./velox/connectors/hive/CMakeLists.txt:22:  OBJECT
./velox/connectors/fuzzer/CMakeLists.txt:15:add_library(velox_fuzzer_connector OBJECT FuzzerConnector.cpp)
./velox/expression/CMakeLists.txt:15:velox_add_library(velox_type_signature OBJECT TypeSignature.cpp)
./velox/common/process/CMakeLists.txt:31:add_library(velox_profiler OBJECT Profiler.cpp)

What is the reason behind this?
Is this something that should be corrected?