diff --git a/src/hotspot/os/bsd/os_bsd.cpp b/src/hotspot/os/bsd/os_bsd.cpp
index fe1feae05a8..071045c6a6e 100644
--- a/src/hotspot/os/bsd/os_bsd.cpp
+++ b/src/hotspot/os/bsd/os_bsd.cpp
@@ -1379,7 +1379,7 @@ void os::print_os_info(outputStream* st) {
 
 #ifdef __APPLE__
 static void print_sysctl_info_string(const char* sysctlkey, outputStream* st, char* buf, size_t size) {
-  if (sysctlbyname(sysctlkey, buf, &size, NULL, 0) >= 0) {
+  if (sysctlbyname(sysctlkey, buf, &size, nullptr, 0) >= 0) {
     st->print_cr("%s:%s", sysctlkey, buf);
   }
 }
@@ -1387,7 +1387,7 @@ static void print_sysctl_info_string(const char* sysctlkey, outputStream* st, ch
 static void print_sysctl_info_uint64(const char* sysctlkey, outputStream* st) {
   uint64_t val;
   size_t size=sizeof(uint64_t);
-  if (sysctlbyname(sysctlkey, &val, &size, NULL, 0) >= 0) {
+  if (sysctlbyname(sysctlkey, &val, &size, nullptr, 0) >= 0) {
     st->print_cr("%s:%llu", sysctlkey, val);
   }
 }
diff --git a/src/hotspot/os/windows/os_windows.cpp b/src/hotspot/os/windows/os_windows.cpp
index 690590b54cf..2b2091700b3 100644
--- a/src/hotspot/os/windows/os_windows.cpp
+++ b/src/hotspot/os/windows/os_windows.cpp
@@ -1946,7 +1946,7 @@ void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
   }
 
   size_t sz_check = sizeof(PROCESSOR_POWER_INFORMATION) * (size_t)proc_count;
-  NTSTATUS status = ::CallNtPowerInformation(ProcessorInformation, NULL, 0, buf, (ULONG) buflen);
+  NTSTATUS status = ::CallNtPowerInformation(ProcessorInformation, nullptr, 0, buf, (ULONG) buflen);
   int max_mhz = -1, current_mhz = -1, mhz_limit = -1;
   bool same_vals_for_all_cpus = true;