public @Nullable PsiClass findClass(final String qualifiedName) {
    if (qualifiedName == null) return null;
    Project project = getProject();
    GlobalSearchScope searchScope = getSearchScope();
    PsiClass mainClass = JavaExecutionUtil.findMainClass(project, qualifiedName, searchScope);
    if (mainClass == null && !PsiNameHelper.getInstance(project).isQualifiedName(qualifiedName)) {
      return findClass(StringUtil.getShortName(qualifiedName), StringUtil.getPackageName(qualifiedName), project, searchScope);
    }
    return mainClass;
  }
public @Nullable PsiClass findClass(final String qualifiedName)