apache/beam · error · RuntimeException

Standard logical type

Error message

Standard logical type '%s' has a zero-argument constructor, but it is not accessible.

What it means

If the logical type class has a zero-argument constructor that is not accessible (IllegalAccessException during getConstructor().newInstance()), SchemaTranslation throws RuntimeException 'has a zero-argument constructor, but it is not accessible'.

Solutions

1. Make the no-arg constructor public.
2. With JPMS, add opens/exports for the package or pass --add-opens <module>/<package>=ALL-UNNAMED.
3. Register a public implementation class for the URN instead of a hidden one.
4. Catch the RuntimeException when decoding and surface a clear schema compatibility error.

Example fix

// before
private IdLogicalType(){}
// after
public IdLogicalType(){}

java.lang.reflect.Constructor<?> c = logicalTypeClass.getConstructor();
if (!java.lang.reflect.Modifier.isPublic(c.getModifiers())
    || !java.lang.reflect.Modifier.isPublic(logicalTypeClass.getModifiers()))
  throw new IllegalStateException("No-arg constructor not accessible");

When it happens

Trigger: Decoding an argument-less logical type whose no-arg constructor is private/package-private, or whose class lives in a JPMS module that does not open its package.

Common situations: Singleton-style logical types with private constructors; modularized apps without --add-opens; builders used instead of public constructors.

Related errors

• Standard logical type
• AutoValue builder class
• Can not call prepareRun
• cannot register Coder : does not have an accessible method…
• cannot register Coder : method named 'of' with arguments…

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/a60698198cc8b08b. Report an issue: GitHub.

Appendix: source

Thrown at sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/SchemaTranslation.java:455

                  e);
            } catch (InvocationTargetException e) {
              throw new RuntimeException(
                  String.format(
                      "Error instantiating logical type '%s' with of('%s') method.",
                      urn, objectName),
                  e);
            }
          } else {
            // Logical type without argument. Construct from constructor without parameter
            try {
              return FieldType.logicalType(logicalTypeClass.getConstructor().newInstance());
            } catch (NoSuchMethodException e) {
              throw new RuntimeException(
                  String.format(
                      "Standard logical type '%s' does not have a zero-argument constructor.", urn),
                  e);
            } catch (IllegalAccessException e) {
              throw new RuntimeException(
                  String.format(
                      "Standard logical type '%s' has a zero-argument constructor, but it is not accessible.",
                      urn),
                  e);
            } catch (ReflectiveOperationException e) {
              throw new RuntimeException(
                  String.format(
                      "Error instantiating logical type '%s' with zero-argument constructor.", urn),
                  e);
            }
          }
        }
        // Special-case for DATETIME and DECIMAL which are logical types in portable representation,
        // but not yet in Java. (https://github.com/apache/beam/issues/19817)
        if (urn.equals(URN_BEAM_LOGICAL_MILLIS_INSTANT)) {
          return FieldType.DATETIME;
        } else if (urn.equals(URN_BEAM_LOGICAL_DECIMAL)) {
          return FieldType.DECIMAL;

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