diff --git a/idea/src/org/jetbrains/jet/plugin/java/JavaElementFinder.java b/idea/src/org/jetbrains/jet/plugin/java/JavaElementFinder.java
index adf84a87b4c..fe2513823e0 100644
--- a/idea/src/org/jetbrains/jet/plugin/java/JavaElementFinder.java
+++ b/idea/src/org/jetbrains/jet/plugin/java/JavaElementFinder.java
@@ -9,7 +9,7 @@ import com.intellij.openapi.fileTypes.FileTypeManager;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.roots.ProjectRootManager;
 import com.intellij.openapi.util.text.StringUtil;
-import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.openapi.vfs.*;
 import com.intellij.psi.*;
 import com.intellij.psi.impl.file.PsiPackageImpl;
 import com.intellij.psi.search.GlobalSearchScope;
@@ -18,18 +18,40 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.plugin.JetFileType;
 
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
+import java.util.*;
 
 public class JavaElementFinder extends PsiElementFinder {
     private final Project project;
     private final PsiManager psiManager;
 
+    private WeakHashMap<GlobalSearchScope, List<JetFile>> jetFiles = new WeakHashMap<GlobalSearchScope, List<JetFile>>();
+
     public JavaElementFinder(Project project) {
         this.project = project;
         psiManager = PsiManager.getInstance(project);
+
+        // Monitoring for files instead of collecting them each time
+        VirtualFileManager.getInstance().addVirtualFileListener(new VirtualFileAdapter() {
+            @Override
+            public void fileCreated(VirtualFileEvent event) {
+                invalidateJetFilesCache();
+            }
+
+            @Override
+            public void fileDeleted(VirtualFileEvent event) {
+                invalidateJetFilesCache();
+            }
+
+            @Override
+            public void fileMoved(VirtualFileMoveEvent event) {
+                invalidateJetFilesCache();
+            }
+
+            @Override
+            public void fileCopied(VirtualFileCopyEvent event) {
+                invalidateJetFilesCache();
+            }
+        });
     }
 
     @Override
@@ -45,7 +67,7 @@ public class JavaElementFinder extends PsiElementFinder {
         if (qualifiedName.startsWith("java.")) return PsiClass.EMPTY_ARRAY;
 
         List<PsiClass> answer = new SmartList<PsiClass>();
-        final List<JetFile> filesInScope = collectProjectFiles(project, scope);
+        final List<JetFile> filesInScope = collectProjectJetFiles(project, scope);
         for (JetFile file : filesInScope) {
             JetNamespace rootNamespace = file.getRootNamespace();
             final String packageName = JetPsiUtil.getFQName(rootNamespace);
@@ -71,7 +93,7 @@ public class JavaElementFinder extends PsiElementFinder {
         Set<String> answer = new HashSet<String>();
 
         String packageFQN = psiPackage.getQualifiedName();
-        for (JetFile psiFile : collectProjectFiles(project, GlobalSearchScope.allScope(project))) {
+        for (JetFile psiFile : collectProjectJetFiles(project, GlobalSearchScope.allScope(project))) {
             final JetNamespace rootNamespace = psiFile.getRootNamespace();
             if (packageFQN.equals(JetPsiUtil.getFQName(rootNamespace))) {
                 answer.add("namespace");
@@ -93,7 +115,7 @@ public class JavaElementFinder extends PsiElementFinder {
 
     @Override
     public PsiPackage findPackage(@NotNull String qualifiedName) {
-        final List<JetFile> psiFiles = collectProjectFiles(project, GlobalSearchScope.allScope(project));
+        final List<JetFile> psiFiles = collectProjectJetFiles(project, GlobalSearchScope.allScope(project));
 
         for (JetFile psiFile : psiFiles) {
             if (qualifiedName.equals(JetPsiUtil.getFQName(psiFile.getRootNamespace()))) {
@@ -108,7 +130,7 @@ public class JavaElementFinder extends PsiElementFinder {
     @Override
     public PsiClass[] getClasses(@NotNull PsiPackage psiPackage, @NotNull GlobalSearchScope scope) {
         List<PsiClass> answer = new SmartList<PsiClass>();
-        final List<JetFile> filesInScope = collectProjectFiles(project, scope);
+        final List<JetFile> filesInScope = collectProjectJetFiles(project, scope);
         String packageFQN = psiPackage.getQualifiedName();
         for (JetFile file : filesInScope) {
             final JetNamespace rootNamespace = file.getRootNamespace();
@@ -125,31 +147,40 @@ public class JavaElementFinder extends PsiElementFinder {
         return answer.toArray(new PsiClass[answer.size()]);
     }
 
+    private synchronized void invalidateJetFilesCache() {
+        jetFiles.clear();
+    }
 
-    private static List<JetFile> collectProjectFiles(final Project project, @NotNull final GlobalSearchScope scope) {
-        final List<JetFile> answer = new ArrayList<JetFile>();
+    private synchronized List<JetFile> collectProjectJetFiles(final Project project, @NotNull final GlobalSearchScope scope) {
+        List<JetFile> cachedFiles = jetFiles.get(scope);
+        
+        if (cachedFiles == null) {
+            final List<JetFile> answer = new ArrayList<JetFile>();
 
+            final FileTypeManager fileTypeManager = FileTypeManager.getInstance();
 
-        final FileTypeManager fileTypeManager = FileTypeManager.getInstance();
-        final PsiManager psiManager = PsiManager.getInstance(project);
+            VirtualFile[] contentRoots = ProjectRootManager.getInstance(project).getContentRoots();
 
-        VirtualFile[] contentRoots = ProjectRootManager.getInstance(project).getContentRoots();
-        CompilerPathsEx.visitFiles(contentRoots, new CompilerPathsEx.FileVisitor() {
-            @Override
-            protected void acceptFile(VirtualFile file, String fileRoot, String filePath) {
-                final FileType fileType = fileTypeManager.getFileTypeByFile(file);
-                if (fileType != JetFileType.INSTANCE) return;
+            CompilerPathsEx.visitFiles(contentRoots, new CompilerPathsEx.FileVisitor() {
+                @Override
+                protected void acceptFile(VirtualFile file, String fileRoot, String filePath) {
+                    final FileType fileType = fileTypeManager.getFileTypeByFile(file);
+                    if (fileType != JetFileType.INSTANCE) return;
 
-                if (scope.accept(file)) {
-                    final PsiFile psiFile = psiManager.findFile(file);
-                    if (psiFile instanceof JetFile) {
-                        answer.add((JetFile) psiFile);
+                    if (scope.accept(file)) {
+                        final PsiFile psiFile = psiManager.findFile(file);
+                        if (psiFile instanceof JetFile) {
+                            answer.add((JetFile) psiFile);
+                        }
                     }
                 }
-            }
-        });
+            });
 
-        return answer;
+            cachedFiles = answer;
+             jetFiles.put(scope, answer);
+        }
+
+        return cachedFiles;
     }
 }