diff --git a/app/build.xml b/app/build.xml
index a9a3d58fb..3d0366a91 100644
--- a/app/build.xml
+++ b/app/build.xml
@@ -137,27 +137,29 @@
     </copy>
 
     <!-- in some cases, pde.jar was not getting built
-	 https://github.com/processing/processing/issues/1792 -->
+         https://github.com/processing/processing/issues/1792 -->
     <delete file="pde.jar" />
 
     <!-- env used to set classpath below -->
     <property environment="env" />
 
     <javac source="11"
-	   target="11"
-	   destdir="bin"
-	   excludes="**/tools/format/**"
-	   encoding="UTF-8"
-	   includeAntRuntime="false"
-	   classpath="../core/library/core.jar;
-                ../core/apple.jar;
-                lib/ant.jar;
-                lib/ant-launcher.jar;
-                lib/jna.jar;
-                lib/jna-platform.jar;
-                lib/VAqua9.jar"
-	   debug="on"
-	   nowarn="true">
+           target="11"
+           destdir="bin"
+           excludes="**/tools/format/**"
+           encoding="UTF-8"
+           includeAntRuntime="false"
+           classpath="../core/library/core.jar;
+                      ../core/apple.jar;
+                      lib/ant.jar;
+                      lib/ant-launcher.jar;
+                      lib/jna.jar;
+                      lib/jna-platform.jar;
+                      lib/VAqua9.jar"
+           debug="on"
+           nowarn="true">
+      <compilerarg value="-Xlint:unchecked" />
+      <compilerarg value="-Xlint:deprecation" />
       <src path="src" />
     </javac>
   </target>
diff --git a/java/libraries/javafx/build.xml b/java/libraries/javafx/build.xml
index cdc6e3b23..6df92bddb 100644
--- a/java/libraries/javafx/build.xml
+++ b/java/libraries/javafx/build.xml
@@ -7,7 +7,10 @@
 
   <target name="clean" description="Clean the build directories">
     <delete dir="bin" />
-    <delete file="${library.path}/javafx.jar" />
+    <!-- <delete file="${library.path}/javafx.jar" /> -->
+    <!-- Remove everything, which includes javafx.jar and files extracted from
+         GluonHQ downloads, but those can be reproduced from the downloaded zips. -->
+    <delete dir="${library.path}" />
   </target>
 
   <condition property="fx.unavailable" value="true">
@@ -129,10 +132,11 @@
     </unzip>
   </target>
 
+  <!--
   <target name="clean-javafx">
     <delete dir="." includes="**/javafx-*-sdk*.zip" />
-    <delete dir="${library.path}" />
   </target>
+  -->
 
   <target name="download-javafx">
     <property name="gluon.version" value="16" />