diff --git a/libs/ui/Fence.cpp b/libs/ui/Fence.cpp
index ed7ccb0b..4ce891e 100644
--- a/libs/ui/Fence.cpp
+++ b/libs/ui/Fence.cpp
@@ -110,7 +110,7 @@
     }
 
     struct sync_file_info* finfo = sync_file_info(mFenceFd);
-    if (finfo == NULL) {
+    if (finfo == nullptr) {
         ALOGE("sync_file_info returned NULL for fd %d", mFenceFd.get());
         return SIGNAL_TIME_INVALID;
     }
diff --git a/libs/ui/GraphicBuffer.cpp b/libs/ui/GraphicBuffer.cpp
index f800627..a66dbc8 100644
--- a/libs/ui/GraphicBuffer.cpp
+++ b/libs/ui/GraphicBuffer.cpp
@@ -76,7 +76,7 @@
     usage_deprecated = 0;
     usage  = 0;
     layerCount = 0;
-    handle = NULL;
+    handle = nullptr;
 }
 
 // deprecated
@@ -143,7 +143,7 @@
         GraphicBufferAllocator& allocator(GraphicBufferAllocator::get());
         allocator.free(handle);
     }
-    handle = NULL;
+    handle = nullptr;
 }
 
 status_t GraphicBuffer::initCheck() const {
@@ -178,7 +178,7 @@
     if (handle) {
         GraphicBufferAllocator& allocator(GraphicBufferAllocator::get());
         allocator.free(handle);
-        handle = 0;
+        handle = nullptr;
     }
     return initWithSize(inWidth, inHeight, inFormat, inLayerCount, inUsage, "[Reallocation]");
 }
@@ -452,7 +452,7 @@
         width = height = stride = format = usage_deprecated = 0;
         layerCount = 0;
         usage = 0;
-        handle = NULL;
+        handle = nullptr;
         ALOGE("unflatten: numFds or numInts is too large: %zd, %zd", numFds, numInts);
         return BAD_VALUE;
     }
@@ -486,7 +486,7 @@
             width = height = stride = format = usage_deprecated = 0;
             layerCount = 0;
             usage = 0;
-            handle = NULL;
+            handle = nullptr;
             ALOGE("unflatten: native_handle_create failed");
             return NO_MEMORY;
         }
@@ -497,7 +497,7 @@
         width = height = stride = format = usage_deprecated = 0;
         layerCount = 0;
         usage = 0;
-        handle = NULL;
+        handle = nullptr;
     }
 
     mId = static_cast<uint64_t>(buf[7]) << 32;
@@ -507,7 +507,7 @@
 
     mOwner = ownHandle;
 
-    if (handle != 0) {
+    if (handle != nullptr) {
         buffer_handle_t importedHandle;
         status_t err = mBufferMapper.importBuffer(handle, uint32_t(width), uint32_t(height),
                 uint32_t(layerCount), format, usage, uint32_t(stride), &importedHandle);
@@ -515,7 +515,7 @@
             width = height = stride = format = usage_deprecated = 0;
             layerCount = 0;
             usage = 0;
-            handle = NULL;
+            handle = nullptr;
             ALOGE("unflatten: registerBuffer failed: %s (%d)", strerror(-err), err);
             return err;
         }
diff --git a/libs/ui/Region.cpp b/libs/ui/Region.cpp
index 3bd3748..224dc2c 100644
--- a/libs/ui/Region.cpp
+++ b/libs/ui/Region.cpp
@@ -820,7 +820,7 @@
     }
 
     if (numRects > (UINT32_MAX / sizeof(Rect))) {
-        android_errorWriteWithInfoLog(0x534e4554, "29983260", -1, NULL, 0);
+        android_errorWriteWithInfoLog(0x534e4554, "29983260", -1, nullptr, 0);
         return NO_MEMORY;
     }
 
diff --git a/libs/ui/tools/lutgen.cpp b/libs/ui/tools/lutgen.cpp
index 97b0822..85a1ceb 100644
--- a/libs/ui/tools/lutgen.cpp
+++ b/libs/ui/tools/lutgen.cpp
@@ -85,11 +85,11 @@
 static int handleCommandLineArgments(int argc, char* argv[]) {
     static constexpr const char* OPTSTR = "h:d:s:t:";
     static const struct option OPTIONS[] = {
-            { "help",       no_argument,       0, 'h' },
-            { "dimension",  required_argument, 0, 'd' },
-            { "source",     required_argument, 0, 's' },
-            { "target",     required_argument, 0, 't' },
-            { 0, 0, 0, 0 }  // termination of the option list
+            { "help",       no_argument,       nullptr, 'h' },
+            { "dimension",  required_argument, nullptr, 'd' },
+            { "source",     required_argument, nullptr, 's' },
+            { "target",     required_argument, nullptr, 't' },
+            { nullptr, 0, nullptr, 0 }  // termination of the option list
     };
 
     int opt;