diff --git a/src/main/java/io/github/linwancen/plugin/show/CopyReferenceSimple.java b/src/main/java/io/github/linwancen/plugin/show/CopyReferenceSimple.java
index 6990fed..ec86a59 100644
--- a/src/main/java/io/github/linwancen/plugin/show/CopyReferenceSimple.java
+++ b/src/main/java/io/github/linwancen/plugin/show/CopyReferenceSimple.java
@@ -23,8 +23,12 @@ public class CopyReferenceSimple extends CopyReferenceAction {
 
     private static final Pattern QUALIFIED_PATTERN = Pattern.compile("[\\w.]+\\.");
 
+    @Override
     protected String getQualifiedName(Editor editor, List<PsiElement> elements) {
         String qualifiedName = super.getQualifiedName(editor, elements);
+        if (qualifiedName == null) {
+            return null;
+        }
         int i = qualifiedName.indexOf("(");
         if (i > 0) {
             return QUALIFIED_PATTERN.matcher(qualifiedName).replaceAll("").replace('#', '.');
diff --git a/src/main/java/io/github/linwancen/plugin/show/doc/PsiClassUtils.java b/src/main/java/io/github/linwancen/plugin/show/doc/PsiClassUtils.java
index 3f317a3..7f8f628 100644
--- a/src/main/java/io/github/linwancen/plugin/show/doc/PsiClassUtils.java
+++ b/src/main/java/io/github/linwancen/plugin/show/doc/PsiClassUtils.java
@@ -50,7 +50,11 @@ public class PsiClassUtils {
     @NotNull
     public static PsiClass[] fullNameToClass(@NotNull String className, @NotNull Project project) {
         JavaPsiFacade javaPsiFacade = JavaPsiFacade.getInstance(project);
-        return javaPsiFacade.findClasses(className, GlobalSearchScope.allScope(project));
+        try {
+            return javaPsiFacade.findClasses(className, GlobalSearchScope.allScope(project));
+        } catch (Throwable e) {
+            return PsiClass.EMPTY_ARRAY;
+        }
     }
 
     @NotNull
diff --git a/src/main/java/io/github/linwancen/plugin/show/line/NewCallRefToPsiDoc.java b/src/main/java/io/github/linwancen/plugin/show/line/NewCallRefToPsiDoc.java
index a6bd35e..8dacbc9 100644
--- a/src/main/java/io/github/linwancen/plugin/show/line/NewCallRefToPsiDoc.java
+++ b/src/main/java/io/github/linwancen/plugin/show/line/NewCallRefToPsiDoc.java
@@ -78,7 +78,7 @@ class NewCallRefToPsiDoc {
             if (methodComment != null) {
                 return methodComment;
             }
-        } catch (Exception ignored) {
+        } catch (Throwable ignored) {
             // ignored
         }
         return null;