diff --git a/make/CompileDemos.gmk b/make/CompileDemos.gmk
index ded03581fc1..e0d7dc6251c 100644
--- a/make/CompileDemos.gmk
+++ b/make/CompileDemos.gmk
@@ -37,9 +37,13 @@ include SetupJavaCompilers.gmk
 include TextFileProcessing.gmk
 include ZipArchive.gmk
 
+# Hook to include the corresponding custom file, if present.
+$(eval $(call IncludeCustomExtension, CompileDemos-pre.gmk))
+
 # Prepare the find cache.
-$(eval $(call FillCacheFind, $(wildcard $(TOPDIR)/src/demo \
-    $(TOPDIR)/src/*/demo)))
+DEMO_SRC_DIRS += $(TOPDIR)/src/demo
+
+$(eval $(call FillCacheFind, $(wildcard $(DEMO_SRC_DIRS))))
 
 # Append demo goals to this variable.
 TARGETS =
@@ -303,7 +307,7 @@ endif
 
 ################################################################################
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, CompileDemos.gmk))
+$(eval $(call IncludeCustomExtension, CompileDemos-post.gmk))
 
 all: $(TARGETS)
 images: $(IMAGES_TARGETS)
diff --git a/make/lib/Lib-java.base.gmk b/make/lib/Lib-java.base.gmk
index d2c5f853c71..37bb4d9da68 100644
--- a/make/lib/Lib-java.base.gmk
+++ b/make/lib/Lib-java.base.gmk
@@ -25,9 +25,13 @@
 
 include LibCommon.gmk
 
+# Hook to include the corresponding custom file, if present.
+$(eval $(call IncludeCustomExtension, lib/Lib-java.base.gmk))
+
 # Prepare the find cache.
-$(eval $(call FillCacheFind, $(wildcard $(TOPDIR)/src/java.base/*/native \
-    $(TOPDIR)/src/*/java.base/*/native)))
+LIB_java.base_SRC_DIRS += $(TOPDIR)/src/java.base/*/native
+
+$(eval $(call FillCacheFind, $(wildcard $(LIB_java.base_SRC_DIRS))))
 
 include CoreLibraries.gmk
 include NetworkingLibraries.gmk
diff --git a/make/lib/Lib-java.desktop.gmk b/make/lib/Lib-java.desktop.gmk
index 156ac901a03..2f193c1a48a 100644
--- a/make/lib/Lib-java.desktop.gmk
+++ b/make/lib/Lib-java.desktop.gmk
@@ -25,9 +25,13 @@
 
 include LibCommon.gmk
 
+# Hook to include the corresponding custom file, if present.
+$(eval $(call IncludeCustomExtension, lib/Lib-java.desktop.gmk))
+
 # Prepare the find cache.
-$(eval $(call FillCacheFind, $(wildcard $(TOPDIR)/src/java.desktop/*/native \
-    $(TOPDIR)/src/*/java.desktop/*/native)))
+LIB_java.desktop_SRC_DIRS += $(TOPDIR)/src/java.desktop/*/native
+
+$(eval $(call FillCacheFind, $(wildcard $(LIB_java.desktop_SRC_DIRS))))
 
 include LibosxLibraries.gmk
 include PlatformLibraries.gmk