diff --git a/build.xml b/build.xml
index 011b9b81..03b90a8a 100644
--- a/build.xml
+++ b/build.xml
@@ -99,7 +99,7 @@ the common tasks and can be called on to run the main aspects of all the sub-scr
 	<target name="deps" depends="ensureBuildDeps, ensureRuntimeDeps, ensureTestDeps, contrib" description="Downloads all dependencies." />
 	
 	<target name="contrib" depends="config-ivy" description="Downloads various non-crucial documentation, sources, etc that are useful when developing lombok.ast.">
-		<ivy:resolve file="buildScripts/ivy.xml" refresh="true" conf="contrib, ecj7, ecj8" />
+		<ivy:resolve file="buildScripts/ivy.xml" refresh="true" conf="contrib, ecj7, ecj8, ecj9" />
 		<ivy:retrieve />
 	</target>
 
@@ -500,12 +500,18 @@ ${sourceWarning}</echo>
 	</target>
 	
 	<target name="test-ecj" depends="dist, contrib" unless="tests.skip">
-		<java jar="lib/ecj7/org.eclipse.custom-ecj.jar" fork="true" failonerror="true">
+		<condition property="ecj.loc" value="lib/ecj9/*" else="lib/ecj8/*">
+			<equals arg1="${ant.java.version}" arg2="9" />
+		</condition>
+		<java classname="org.eclipse.jdt.internal.compiler.batch.Main" fork="true" failonerror="true">
+			<classpath path="${ecj.loc}" />
 			<jvmarg value="-javaagent:dist/lombok.jar=ecj" />
 			<arg value="-source" />
 			<arg value="1.6" />
 			<arg value="-target" />
 			<arg value="1.6" />
+			<arg value="-cp" />
+			<arg value="dist/lombok.jar" />
 			<arg value="test/ecj/SimpleTest.java" />
 		</java>
 	</target>
diff --git a/buildScripts/ivy.xml b/buildScripts/ivy.xml
index 45360e57..6cc3cce8 100644
--- a/buildScripts/ivy.xml
+++ b/buildScripts/ivy.xml
@@ -11,6 +11,7 @@
 		<conf name="contrib" />
 		<conf name="ecj7" />
 		<conf name="ecj8" />
+		<conf name="ecj9" />
 		<conf name="javac6" />
 		<conf name="javac7" />
 	</configurations>
@@ -40,7 +41,9 @@
 		<dependency org="net.java.openjdk.custom" name="javac6" rev="1.6.0.18" conf="javac6->runtime; contrib->sources" />
 		<dependency org="net.java.openjdk.custom" name="javac7" rev="1.7.0" conf="javac7->runtime; contrib->sources" />
 		<dependency org="org.eclipse.custom" name="ecj" rev="4.3.1" conf="ecj7->default; contrib->sources" />
-		<dependency org="org.eclipse.jdt.core.compiler" name="ecj" rev="4.6.1" conf="ecj8->default; contrib->sources; eclipseBuild->default" />
+		<dependency org="org.eclipse.jdt.core.compiler" name="ecj" rev="4.6.1" conf="ecj8->default; contrib->sources" />
+		<dependency org="org.eclipse.tycho" name="org.eclipse.jdt.core" rev="3.13.50.v20171007-0855" conf="ecj9->default; eclipseBuild->default" />
+		<dependency org="org.eclipse.tycho" name="org.eclipse.jdt.compiler.apt" rev="1.3.50.v20170920-0950" conf="ecj9->default; eclipseBuild->default" />
 		
 		<dependency org="netbeans.org" name="boot" rev="6.8beta" conf="netbeansBuild->build" />
 		<dependency org="netbeans.org" name="openide.modules" rev="6.8beta" conf="netbeansBuild->build" />