diff --git a/java/execution/openapi/src/com/intellij/execution/JavaExecutionUtil.java b/java/execution/openapi/src/com/intellij/execution/JavaExecutionUtil.java
index 42ed3830364a..453cbcb0d6cd 100644
--- a/java/execution/openapi/src/com/intellij/execution/JavaExecutionUtil.java
+++ b/java/execution/openapi/src/com/intellij/execution/JavaExecutionUtil.java
@@ -26,6 +26,7 @@ import com.intellij.execution.util.ExecutionErrorDialog;
 import com.intellij.openapi.actionSystem.DataContext;
 import com.intellij.openapi.module.Module;
 import com.intellij.openapi.module.ModuleUtilCore;
+import com.intellij.openapi.project.DumbService;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Condition;
 import com.intellij.openapi.util.text.StringUtil;
@@ -168,7 +169,7 @@ public class JavaExecutionUtil {
 
   @Nullable
   public static PsiClass findMainClass(final Project project, final String mainClassName, final GlobalSearchScope scope) {
-    if (project.isDefault()) return null;
+    if (project.isDefault() || DumbService.isDumb(project)) return null;
     final PsiManager psiManager = PsiManager.getInstance(project);
     final String shortName = StringUtil.getShortName(mainClassName);
     final String packageName = StringUtil.getPackageName(mainClassName);