JetBrains/intellij-community · error · ConfigurationException

{0} is not a valid package name

Error message

{0} is not a valid package name

What it means

Thrown by BasePackageParameterFactory.validate() in the new-project wizard when the 'Base package' field contains a string that is not a valid Java qualified package name. Validation uses PsiNameHelperImpl.isQualifiedName(), which enforces Java identifier segments separated by dots. The error is a ConfigurationException shown directly in the wizard UI.

Source

Thrown at java/java-impl/src/com/intellij/openapi/module/BasePackageParameterFactory.java:80

      @Override
      public String getValue() {
        return myField.getText();
      }

      @Override
      public Map<String, String> getValues() {
        HashMap<String, String> map = new HashMap<>(2);
        map.put(getId(), getValue());
        map.put("IJ_BASE_PACKAGE_DIR", getValue().replace('.', '/'));
        map.put("IJ_BASE_PACKAGE_PREFIX", StringUtil.isEmpty(getValue()) ? "" : getValue() + ".");
        return map;
      }

      @Override
      public boolean validate() throws ConfigurationException {
        String value = getValue();
        if (!StringUtil.isEmpty(value) && !PsiNameHelperImpl.getInstance().isQualifiedName(value)) {
          throw new ConfigurationException(JavaBundle.message("base.package.project.wizard.error.x.not.valid.package", value));
        }
        PropertiesComponent.getInstance().setValue(IJ_BASE_PACKAGE, value);
        return true;
      }
    };
  }

  @Override
  public String detectParameterValue(Project project) {
    PsiPackage root = JavaPsiFacade.getInstance(project).findPackage("");
    if (root == null) return null;
    String name = getBasePackage(root, GlobalSearchScope.projectScope(project)).getQualifiedName();
    return StringUtil.isEmpty(name) ? null : name;
  }

  private static PsiPackage getBasePackage(PsiPackage pack, GlobalSearchScope scope) {
    List<PsiPackage> subPackages = ContainerUtil.filter(pack.getSubPackages(scope), PACKAGE_CONDITION);
    return subPackages.size() == 1 ? getBasePackage(subPackages.get(0), scope) : pack;

View on GitHub (pinned to be881553f2)

Solutions

1. Correct the value in the 'Base package' field to dot-separated Java identifiers, e.g. com.example.myapp (segments must start with a letter, $ or _ and contain only letters, digits, $ or _).
2. Remove leading/trailing dots, double dots, hyphens and whitespace from the field.
3. If the value looks correct, check for invisible characters (non-breaking space, trailing newline) pasted from a browser or chat message.
4. Leave the field empty if the template allows a default root package.

Example fix

// before (wizard field value)
com.my-app.
// after
com.myapp

PsiNameHelper helper = PsiNameHelper.getInstance(project);
String value = basePackageField.getText().trim();
if (!value.isEmpty() && !helper.isQualifiedName(value)) {
  // show inline error instead of letting validate() throw
  report("Not a valid Java package name: " + value);
}

try { parameter.validate(); } catch (ConfigurationException e) { /* show e.getMessage() in wizard, keep dialog open */ }

When it happens

Trigger: Entering values like 'com.example.mypackage.' (trailing dot), 'com.1example' (segment starting with a digit), 'my-package' (hyphen), 'com..example' (empty segment), or whitespace anywhere in the base package field of a Java project wizard, then pressing Next/Finish.

Common situations: Copy-pasting a package path from a file system directory or Maven groupId that is not a legal Java package; pasting with a trailing newline/space; templates or automation scripts that inject an empty or malformed base package; users assuming hyphens are allowed because the folder name allows them.

Related errors

• Invalid package name: {0}
• ''{0}'' is invalid parameter class package name
• ''{0}'' is invalid destination package name
• replace.constructor.builder.error.invalid.builder.package.na
• illegal flag combination ''{0}'' and ''{1}'' in ''{2}''

AI-assisted analysis of JetBrains/intellij-community@be881553f2 (2026-08-14). Data as JSON: /api/errors/e0382ad784cba832. Report an issue: GitHub.