diff --git a/jps/jps-builders-6/src/org/jetbrains/jps/javac/JavacFileManager.java b/jps/jps-builders-6/src/org/jetbrains/jps/javac/JavacFileManager.java
index 60e00c99c0be..0a83f3cc3edc 100644
--- a/jps/jps-builders-6/src/org/jetbrains/jps/javac/JavacFileManager.java
+++ b/jps/jps-builders-6/src/org/jetbrains/jps/javac/JavacFileManager.java
@@ -165,11 +165,14 @@ class JavacFileManager extends ForwardingJavaFileManager<StandardJavaFileManager
     if (mySourceTransformers.isEmpty()) {
       return originalObjects;
     }
-    final List<JavaFileObject> wrapped = new ArrayList<JavaFileObject>();
+    List<JavaFileObject> wrapped = null;
     for (JavaFileObject fo : originalObjects) {
+      if (wrapped == null) {
+        wrapped = new ArrayList<JavaFileObject>(); // lazy init
+      }
       wrapped.add(JavaFileObject.Kind.SOURCE.equals(fo.getKind())? new TransformableJavaFileObject(fo, mySourceTransformers) : fo);
     }
-    return wrapped;
+    return wrapped != null? wrapped : originalObjects;
   }
   
   @Override
diff --git a/jps/jps-builders-6/src/org/jetbrains/jps/javac/JavacMain.java b/jps/jps-builders-6/src/org/jetbrains/jps/javac/JavacMain.java
index ebfe7c5b85cf..8b0750608b6e 100644
--- a/jps/jps-builders-6/src/org/jetbrains/jps/javac/JavacMain.java
+++ b/jps/jps-builders-6/src/org/jetbrains/jps/javac/JavacMain.java
@@ -72,8 +72,9 @@ public class JavacMain {
     }
 
     final boolean usingJavac = compilingTool instanceof JavacCompilerTool;
+    final boolean javacBefore9 = isJavacBefore9(compilingTool);
     final JavacFileManager fileManager = new JavacFileManager(
-      new ContextImpl(compiler, diagnosticConsumer, outputSink, canceledStatus, canUseOptimizedFileManager(compilingTool)), JavaSourceTransformer.getTransformers()
+      new ContextImpl(compiler, diagnosticConsumer, outputSink, canceledStatus, javacBefore9), JavaSourceTransformer.getTransformers()
     );
 
     if (!platformClasspath.isEmpty()) {
@@ -140,15 +141,19 @@ public class JavacMain {
         }
       }
 
-      try {
-        // ensure the source path is set;
-        // otherwise, if not set, javac attempts to search both classes and sources in classpath;
-        // so if some classpath jars contain sources, it will attempt to compile them
-        fileManager.setLocation(StandardLocation.SOURCE_PATH, sourcePath);
-      }
-      catch (IOException e) {
-        fileManager.getContext().reportMessage(Diagnostic.Kind.ERROR, e.getMessage());
-        return false;
+      if (javacBefore9 || !sourcePath.isEmpty()) {
+        try {
+          // ensure the source path is set;
+          // otherwise, if not set, javac attempts to search both classes and sources in classpath;
+          // so if some classpath jars contain sources, it will attempt to compile them
+          // starting from javac9 it seems that setting empty source path may affect module compilation logic, so starting from javac9
+          // we avoid forcing empty sourcepath
+          fileManager.setLocation(StandardLocation.SOURCE_PATH, sourcePath);
+        }
+        catch (IOException e) {
+          fileManager.getContext().reportMessage(Diagnostic.Kind.ERROR, e.getMessage());
+          return false;
+        }
       }
 
       //noinspection IOResourceOpenedButNotSafelyClosed
@@ -227,7 +232,7 @@ public class JavacMain {
     });
   }
 
-  private static boolean canUseOptimizedFileManager(JavaCompilingTool compilingTool) {
+  private static boolean isJavacBefore9(JavaCompilingTool compilingTool) {
     // since java 9 internal API's used by the optimizedFileManager have changed
     return compilingTool instanceof JavacCompilerTool && (JAVA_RUNTIME_VERSION.startsWith("1.8.") || JAVA_RUNTIME_VERSION.startsWith("1.7.") || JAVA_RUNTIME_VERSION.startsWith("1.6."));
   }