diff --git a/src/main/java/meghanada/junit/TestRunner.java b/src/main/java/meghanada/junit/TestRunner.java
index 393397cf3..b3640ae8f 100644
--- a/src/main/java/meghanada/junit/TestRunner.java
+++ b/src/main/java/meghanada/junit/TestRunner.java
@@ -12,7 +12,6 @@
 import meghanada.reflect.ClassIndex;
 import meghanada.reflect.asm.CachedASMReflector;
 import meghanada.store.ProjectDatabaseHelper;
-import meghanada.utils.FileUtils;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.junit.runner.JUnitCore;
@@ -59,7 +58,7 @@ public static void main(String... args) throws Exception {
   private void cleanup() throws Exception {
     ProjectDatabaseHelper.shutdown();
     String p = System.getProperty(TEMP_PROJECT_SETTING_DIR);
-    FileUtils.deleteFiles(new File(p), true);
+    org.apache.commons.io.FileUtils.deleteDirectory(new File(p));
   }
 
   private List<Class<?>> getTestClass(String testName) throws ClassNotFoundException {
diff --git a/src/main/java/meghanada/location/LocationSearcher.java b/src/main/java/meghanada/location/LocationSearcher.java
index a102c4e95..75d3518d3 100644
--- a/src/main/java/meghanada/location/LocationSearcher.java
+++ b/src/main/java/meghanada/location/LocationSearcher.java
@@ -638,7 +638,7 @@ private Location searchLocationFromDecompileFile(
       }
       return null;
     } finally {
-      FileUtils.deleteFiles(output, false);
+      org.apache.commons.io.FileUtils.deleteDirectory(output);
     }
   }
 
diff --git a/src/main/java/meghanada/project/Project.java b/src/main/java/meghanada/project/Project.java
index e4e1b9f7b..fe30f1ac5 100644
--- a/src/main/java/meghanada/project/Project.java
+++ b/src/main/java/meghanada/project/Project.java
@@ -840,7 +840,7 @@ public void clearCache() throws IOException {
     System.setProperty(PROJECT_ROOT_KEY, this.projectRootPath);
     final File projectSettingDir = new File(Config.load().getProjectSettingDir());
     log.info("clear cache {}", projectSettingDir);
-    FileUtils.deleteFiles(projectSettingDir, false);
+    org.apache.commons.io.FileUtils.deleteDirectory(projectSettingDir);
   }
 
   private Optional<Properties> readFormatPropertiesFromFile() {
diff --git a/src/main/java/meghanada/reflect/ClassIndex.java b/src/main/java/meghanada/reflect/ClassIndex.java
index 89f03f752..afdfc0977 100644
--- a/src/main/java/meghanada/reflect/ClassIndex.java
+++ b/src/main/java/meghanada/reflect/ClassIndex.java
@@ -19,6 +19,7 @@
 public class ClassIndex implements CandidateUnit, Cloneable, Serializable, Storable {
 
   public static final String ENTITY_TYPE = "ClassIndex";
+  public static final String FILE_ENTITY_TYPE = "ClassIndexFile";
   private static final long serialVersionUID = 4833311903131990013L;
 
   // fqcn
@@ -33,6 +34,7 @@ public class ClassIndex implements CandidateUnit, Cloneable, Serializable, Stora
   private String filePath;
   private MemberType memberType = MemberType.CLASS;
   private EntityId entityID;
+  public transient boolean loaded;
 
   public ClassIndex(
       final String declaration, final List<String> typeParameters, final List<String> supers) {
diff --git a/src/main/java/meghanada/reflect/asm/CachedASMReflector.java b/src/main/java/meghanada/reflect/asm/CachedASMReflector.java
index 475a76753..d60e3aef7 100644
--- a/src/main/java/meghanada/reflect/asm/CachedASMReflector.java
+++ b/src/main/java/meghanada/reflect/asm/CachedASMReflector.java
@@ -133,13 +133,29 @@ public void createClassIndexes() {
         .forEach(
             wrapIOConsumer(
                 root -> {
-                  // TODO is loaded ?
-                  final ASMReflector reflector = ASMReflector.getInstance();
-                  reflector
-                      .getClasses(root)
-                      .entrySet()
-                      .parallelStream()
-                      .forEach(entry -> addClassIndex(entry.getKey(), entry.getValue()));
+                  String name = root.getName();
+                  if (name.endsWith(".jar")
+                      && !name.endsWith("SNAPSHOT.jar")
+                      && ProjectDatabaseHelper.getLoadJar(root.getPath())) {
+                    List<ClassIndex> indexes =
+                        ProjectDatabaseHelper.getClassIndexes(root.getPath());
+
+                    for (ClassIndex index : indexes) {
+                      index.loaded = true;
+                      String fqcn = index.getRawDeclaration();
+                      this.globalClassIndex.put(fqcn, index);
+                    }
+                  } else {
+                    final ASMReflector reflector = ASMReflector.getInstance();
+                    reflector
+                        .getClasses(root)
+                        .entrySet()
+                        .parallelStream()
+                        .forEach(entry -> addClassIndex(entry.getKey(), entry.getValue()));
+                    if (name.endsWith(".jar") && !name.endsWith("SNAPSHOT.jar")) {
+                      ProjectDatabaseHelper.saveLoadJar(root.getPath());
+                    }
+                  }
                 }));
 
     this.updateClassIndexFromDirectory();
@@ -147,18 +163,20 @@ public void createClassIndexes() {
   }
 
   private void saveAllClassIndexes() {
-    List<ClassIndex> jarIndexes =
-        globalClassIndex
-            .values()
-            .stream()
-            .filter(classIndex -> classIndex.getFilePath().endsWith(".jar"))
-            .collect(Collectors.toList());
-    List<ClassIndex> otherIndexes =
-        globalClassIndex
-            .values()
-            .stream()
-            .filter(classIndex -> !classIndex.getFilePath().endsWith(".jar"))
-            .collect(Collectors.toList());
+    List<ClassIndex> jarIndexes = new ArrayList<>();
+    List<ClassIndex> otherIndexes = new ArrayList<>();
+    globalClassIndex
+        .values()
+        .forEach(
+            index -> {
+              if (!index.getFilePath().endsWith(".jar")) {
+                otherIndexes.add(index);
+              } else {
+                if (!index.loaded) {
+                  jarIndexes.add(index);
+                }
+              }
+            });
 
     ProjectDatabaseHelper.saveClassIndexes(jarIndexes, false);
     ProjectDatabaseHelper.saveClassIndexes(otherIndexes, true);
diff --git a/src/main/java/meghanada/store/ProjectDatabase.java b/src/main/java/meghanada/store/ProjectDatabase.java
index 28c74333f..ed4c45cfb 100644
--- a/src/main/java/meghanada/store/ProjectDatabase.java
+++ b/src/main/java/meghanada/store/ProjectDatabase.java
@@ -45,7 +45,6 @@
 import meghanada.Main;
 import meghanada.config.Config;
 import meghanada.project.Project;
-import meghanada.utils.FileUtils;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -89,7 +88,7 @@ private ProjectDatabase() {
                 }));
   }
 
-  public static ProjectDatabase getInstance() {
+  public static synchronized ProjectDatabase getInstance() {
     checkChangeProject();
     if (projectDatabase != null) {
       projectDatabase.open();
@@ -330,7 +329,7 @@ private void open() {
         if (nonNull(files)) {
           for (File file : files) {
             if (file.isDirectory() && file.getName().startsWith(name) && !file.equals(base)) {
-              FileUtils.deleteFiles(file, true);
+              org.apache.commons.io.FileUtils.deleteDirectory(file);
             }
           }
         }
@@ -339,7 +338,7 @@ private void open() {
           this.environment = Environments.newInstance(base);
         } catch (ExodusException ex) {
           // try re-create
-          FileUtils.deleteFiles(base, true);
+          org.apache.commons.io.FileUtils.deleteDirectory(base);
           this.environment = Environments.newInstance(base);
         }
         this.entityStore = PersistentEntityStores.newInstance(environment, STORE_NAME);
diff --git a/src/main/java/meghanada/store/ProjectDatabaseHelper.java b/src/main/java/meghanada/store/ProjectDatabaseHelper.java
index 2519eeb34..a0640e5e2 100644
--- a/src/main/java/meghanada/store/ProjectDatabaseHelper.java
+++ b/src/main/java/meghanada/store/ProjectDatabaseHelper.java
@@ -1,6 +1,7 @@
 package meghanada.store;
 
 import static java.util.Objects.isNull;
+import static java.util.Objects.nonNull;
 
 import java.io.File;
 import java.io.IOException;
@@ -46,6 +47,45 @@ public static void saveClassIndexes(Collection<ClassIndex> indexes, boolean allo
     }
   }
 
+  public static boolean getLoadJar(String filePath) {
+    ProjectDatabase database = ProjectDatabase.getInstance();
+    return database.computeInReadonly(
+        txn -> {
+          EntityIterable it = txn.find(ClassIndex.FILE_ENTITY_TYPE, "filePath", filePath);
+          return nonNull(it.getFirst());
+        });
+  }
+
+  public static void saveLoadJar(String filePath) {
+    ProjectDatabase database = ProjectDatabase.getInstance();
+    database.execute(
+        txn -> {
+          EntityIterable it = txn.find(ClassIndex.FILE_ENTITY_TYPE, "filePath", filePath);
+          if (nonNull(it.getFirst())) {
+            return false;
+          }
+          Entity entity = txn.newEntity(ClassIndex.FILE_ENTITY_TYPE);
+          entity.setProperty("filePath", filePath);
+          return true;
+        });
+  }
+
+  public static List<ClassIndex> getClassIndexes(String filePath) {
+    ProjectDatabase database = ProjectDatabase.getInstance();
+    return database.find(
+        ClassIndex.ENTITY_TYPE,
+        "filePath",
+        filePath,
+        entity -> {
+          try (InputStream in = entity.getBlob(ProjectDatabase.SERIALIZE_KEY)) {
+            return Serializer.readObject(in, ClassIndex.class);
+          } catch (Exception e) {
+            log.warn(e.getMessage());
+            return null;
+          }
+        });
+  }
+
   public static File getClassFile(String fqcn) {
     ProjectDatabase database = ProjectDatabase.getInstance();
     Optional<String> res =
diff --git a/src/main/java/meghanada/utils/FileUtils.java b/src/main/java/meghanada/utils/FileUtils.java
index af996d581..e78b4a9e5 100644
--- a/src/main/java/meghanada/utils/FileUtils.java
+++ b/src/main/java/meghanada/utils/FileUtils.java
@@ -121,36 +121,6 @@ public static Optional<File> collectFile(final File root, final String ext) thro
     }
   }
 
-  public static void deleteFiles(final File root, final boolean deleteRoot) throws IOException {
-    if (!root.exists()) {
-      return;
-    }
-    Files.walkFileTree(
-        root.toPath(),
-        new SimpleFileVisitor<Path>() {
-          @Override
-          public FileVisitResult visitFile(final Path file, final BasicFileAttributes attrs)
-              throws IOException {
-            Files.delete(file);
-            return FileVisitResult.CONTINUE;
-          }
-
-          @Override
-          public FileVisitResult postVisitDirectory(final Path dir, final IOException exc)
-              throws IOException {
-            if (deleteRoot) {
-              Files.delete(dir);
-            } else {
-              if (!dir.toFile().equals(root)) {
-                Files.delete(dir);
-              }
-            }
-
-            return FileVisitResult.CONTINUE;
-          }
-        });
-  }
-
   public static boolean filterFile(final File file) {
     final Config config = Config.load();
 
diff --git a/src/test/java/meghanada/GradleTestBase.java b/src/test/java/meghanada/GradleTestBase.java
index baf9e55a6..ee8623cdf 100644
--- a/src/test/java/meghanada/GradleTestBase.java
+++ b/src/test/java/meghanada/GradleTestBase.java
@@ -125,6 +125,7 @@ protected static File getTestOutput() {
   public static void setupReflector() throws Exception {
     setupProject();
     CachedASMReflector cachedASMReflector = CachedASMReflector.getInstance();
+    cachedASMReflector.getGlobalClassIndex().clear();
     addClasspath(cachedASMReflector);
     final Stopwatch stopwatch = Stopwatch.createStarted();
     cachedASMReflector.createClassIndexes();
@@ -136,11 +137,11 @@ public static void shutdown() throws IOException, InterruptedException {
     ProjectDatabaseHelper.shutdown();
     String p = System.getProperty(TEMP_PROJECT_SETTING_DIR);
     File file = new File(p);
-    FileUtils.deleteFiles(file, true);
+    org.apache.commons.io.FileUtils.deleteDirectory(file);
     assert !file.exists();
     String tempPath = GradleProject.getTempPath();
     if (nonNull(tempPath)) {
-      FileUtils.deleteFiles(new File(tempPath), true);
+      org.apache.commons.io.FileUtils.deleteDirectory(new File(tempPath));
     }
     log.info("deleted database {}", file);
   }
diff --git a/src/test/java/meghanada/project/gradle/GradleProjectTest.java b/src/test/java/meghanada/project/gradle/GradleProjectTest.java
index 7ec5a6d29..7315e19dd 100644
--- a/src/test/java/meghanada/project/gradle/GradleProjectTest.java
+++ b/src/test/java/meghanada/project/gradle/GradleProjectTest.java
@@ -14,7 +14,6 @@
 import meghanada.project.Project;
 import meghanada.reflect.asm.CachedASMReflector;
 import meghanada.store.ProjectDatabaseHelper;
-import meghanada.utils.FileUtils;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.junit.AfterClass;
@@ -36,10 +35,10 @@ public static void shutdown() throws Exception {
     ProjectDatabaseHelper.shutdown();
     String p = System.getProperty(TEMP_PROJECT_SETTING_DIR);
     File file = new File(p);
-    FileUtils.deleteFiles(file, true);
+    org.apache.commons.io.FileUtils.deleteDirectory(file);
     String tempPath = GradleProject.getTempPath();
     if (nonNull(tempPath)) {
-      FileUtils.deleteFiles(new File(tempPath), true);
+      org.apache.commons.io.FileUtils.deleteDirectory(new File(tempPath));
     }
   }
 
diff --git a/src/test/java/meghanada/store/ProjectDatabaseTest.java b/src/test/java/meghanada/store/ProjectDatabaseTest.java
index 00d8523e2..e399e9262 100644
--- a/src/test/java/meghanada/store/ProjectDatabaseTest.java
+++ b/src/test/java/meghanada/store/ProjectDatabaseTest.java
@@ -13,7 +13,6 @@
 import java.util.List;
 import meghanada.project.Project;
 import meghanada.reflect.ClassIndex;
-import meghanada.utils.FileUtils;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Ignore;
@@ -31,8 +30,7 @@ public void setup() throws Exception {
     tempDir.deleteOnExit();
     final String path = tempDir.getCanonicalPath();
     System.setProperty(TEMP_PROJECT_SETTING_DIR, path);
-    FileUtils.deleteFiles(new File(path), true);
-
+    org.apache.commons.io.FileUtils.deleteDirectory(new File(path));
     String projectRoot = new File(".").getCanonicalPath();
     System.setProperty(Project.PROJECT_ROOT_KEY, projectRoot);
 
@@ -45,7 +43,7 @@ public void tearDown() throws InterruptedException, IOException {
       database.shutdown();
     }
     String p = System.getProperty(TEMP_PROJECT_SETTING_DIR);
-    FileUtils.deleteFiles(new File(p), true);
+    org.apache.commons.io.FileUtils.deleteDirectory(new File(p));
   }
 
   @Test