diff --git a/ecj.spec b/ecj.spec
index 3c218e5..b1ae279 100644
--- a/ecj.spec
+++ b/ecj.spec
@@ -43,8 +43,7 @@ Patch0:         %{name}-rpmdebuginfo.patch
 # Include java API stubs in build with java < 15
 Patch1:         javaAPI.patch
 BuildRequires:  ant
-BuildRequires:  java-devel = 1.8.0
-BuildRequires:  java-devel = 11
+BuildRequires:  java-devel >= 10
 BuildRequires:  javapackages-local
 BuildRequires:  unzip
 BuildArch:      noarch
@@ -74,7 +73,7 @@ rm META-INF/ECLIPSE_*
 %build
 
 mkdir -p build/classes
-javac --patch-module java.compiler=java15api-src -XDignore.symbol.file=true -d build/classes -source 11 -target 11 \
+javac --patch-module java.compiler=java15api-src -XDignore.symbol.file=true -d build/classes --release 10 \
   $(find java15api-src/javax -name \*.java | xargs)
 jar -cf java15api.jar -C build/classes .
 # Remove everything except the jar, since ant looks for java files in "."
@@ -82,7 +81,7 @@ rm -rf java15api-src build/classes
 
 ant \
 %if %{?pkg_vcmp:%pkg_vcmp java-devel < 15}%{!?pkg_vcmp:1}
-	-Djavaapi=java15api.jar -Drtjar=%{_jvmdir}/jre-1.8.0/lib/rt.jar \
+	-Djavaapi=java15api.jar \
 %endif
 	build
 
@@ -96,8 +95,7 @@ install -pm 0644 java15api.jar %{buildroot}%{_javadir}/%{name}/java15api.jar
 install -dm 0755 %{buildroot}%{_mavenpomdir}/%{name}
 install -pm 0644 %{SOURCE2} %{buildroot}%{_mavenpomdir}/%{name}/ecj.pom
 %add_maven_depmap %{name}/ecj.pom %{name}/ecj.jar -a "org.eclipse.jdt:core,org.eclipse.jdt.core.compiler:ecj,org.eclipse.tycho:org.eclipse.jdt.core,org.eclipse.tycho:org.eclipse.jdt.compiler.apt"
-install -pm 0644 %{SOURCE3} %{buildroot}%{_mavenpomdir}/%{name}/java15api.pom
-%add_maven_depmap %{name}/java15api.pom %{name}/java15api.jar -a "org.eclipse:java9api"
+%add_maven_depmap org.eclipse:java15api:15 %{name}/java15api.jar -a "org.eclipse:java9api,org.eclipse:java10api"
 
 # Install the ecj wrapper script
 %jpackage_script org.eclipse.jdt.internal.compiler.batch.Main '' '' ecj ecj true
diff --git a/javaAPI.patch b/javaAPI.patch
index ee011ed..b71762e 100644
--- a/javaAPI.patch
+++ b/javaAPI.patch
@@ -1,25 +1,24 @@
 --- build.xml.orig	2020-09-02 22:05:12.000000000 +0200
 +++ build.xml	2021-03-16 14:41:19.331235267 +0100
-@@ -18,6 +18,10 @@
+@@ -18,16 +18,20 @@
  	<property name="output" value="bin" />
  	<property name="jar_file" value="ecj.jar" />
  
 +	<path id="build.path">
 +		<pathelement path="${javaapi}"/>
-+		<pathelement path="${rtjar}"/>
 +	</path>
  	<target name="build">
  		<delete file="${basedir}/${jar_file}" failonerror="no" />
  		<delete dir="${output}" failonerror="no" />
-@@ -25,9 +29,11 @@
+ 		<mkdir dir="${output}" />
  
  		<javac srcdir="${basedir}" destdir="${output}"
++					encoding="utf-8"
  					debuglevel="lines,source"
-+                    encoding="utf-8"
-+                    bootclasspathref="build.path"
  					source="1.8"
  					target="1.8">
- 			<compilerarg line="-Xlint:none"/>
+-			<compilerarg line="-Xlint:none"/>
++			<compilerarg line="-Xlint:none" value="-Xbootclasspath/p:${toString:build.path}"/>
  		</javac>
  
  		<delete file="${basedir}/META-INF/MANIFEST.MF" failonerror="false"/>