‘fixed’ ecj testing on JDK9 by requiring that you download the Oracle8 rt.jar. Fortunately, we already had an optional ant task to fetch this. I’ve simply made it less optional.

build.xml

@@ -503,7 +503,7 @@ ${sourceWarning}</echo>
 		</ivy:compile>
 	</target>
 	
-	<target name="test-ecj" depends="dist, contrib" unless="tests.skip">
+	<target name="test-ecj" depends="dist, contrib, setupJavaOracle8TestEnvironment" unless="tests.skip">
 		<condition property="ecj.loc" value="lib/ecj9/*" else="lib/ecj8/*">
 			<equals arg1="${ant.java.version}" arg2="9" />
 		</condition>

test/core/src/lombok/RunTestsViaEcj.java

@@ -24,7 +24,6 @@ package lombok;
 import java.io.File;
 import java.io.StringWriter;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -131,7 +130,6 @@ public class RunTestsViaEcj extends AbstractRunTests {
 	
 	private FileSystem createFileSystem(File file) {
 		List<String> classpath = new ArrayList<String>();
-		classpath.addAll(Arrays.asList(System.getProperty("sun.boot.class.path").split(File.pathSeparator)));
 		for (Iterator<String> i = classpath.iterator(); i.hasNext();) {
 			if (FileSystem.getClasspath(i.next(), "UTF-8", null) == null) {
 				i.remove();
@@ -139,6 +137,7 @@ public class RunTestsViaEcj extends AbstractRunTests {
 		}
 		if (new File("bin").exists()) classpath.add("bin");
 		classpath.add("dist/lombok.jar");
+		classpath.add("lib/oracleJDK8Environment/rt.jar");
 		classpath.add("lib/test/commons-logging-commons-logging.jar");
 		classpath.add("lib/test/org.slf4j-slf4j-api.jar");
 		classpath.add("lib/test/org.slf4j-slf4j-ext.jar");