apache/beam · error · RuntimeException

Failed to construct instance from constructor +…

Error message

Failed to construct instance from constructor + factoryClass.getName()

What it means

InstanceBuilder.buildFromConstructor() wraps InvocationTargetException, InstantiationException and IllegalAccessException into RuntimeException 'Failed to construct instance from constructor ' + factoryClass.getName(). The constructor was found but invoking it failed: it threw an exception, the class is abstract/interface, or access was denied.

Solutions

Inspect the wrapped cause (getCause()) to see the constructor's own exception
Ensure the configured class is concrete (not abstract or an interface)
Make the constructor public, or fix argument validation inside the constructor
Fix the invalid arguments that made the constructor throw

Example fix

// before
new InstanceBuilder().fromClassName("java.util.List").build(); // interface
// after
new InstanceBuilder().fromClassName("java.util.ArrayList").build();

Defensive patterns

Strategy: try-catch

Validate before calling

if (java.lang.reflect.Modifier.isAbstract(factoryClass.getModifiers())) { throw new IllegalStateException("cannot instantiate abstract class " + factoryClass.getName()); }

Try / catch

try { instance = builder.build(); } catch (RuntimeException e) { log.error("ctor failed", e.getCause()); throw e; }

Prevention

Configure only concrete, instantiable classes
Inspect getCause() for the constructor's own exception
Keep constructors side-effect-light and fail fast

When it happens

Trigger: Constructor body threw an exception (wrapped cause); newInstance called on an abstract class or interface; constructor not accessible due to access control.

Common situations: Abstract base class configured as a concrete factory class; constructor validating arguments and throwing; private constructor invoked reflectively.

Related errors

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/ea27e196437b7388. Report an issue: GitHub.

Appendix: source

Thrown at sdks/java/core/src/main/java/org/apache/beam/sdk/util/InstanceBuilder.java:263

      checkState(
          type.isAssignableFrom(factoryClass),
          "Instance type %s must be assignable to %s",
          factoryClass.getName(),
          type.getSimpleName());

      if (!constructor.isAccessible()) {
        constructor.setAccessible(true);
      }

      Object[] args = arguments.toArray(new Object[arguments.size()]);
      return type.cast(constructor.newInstance(args));

    } catch (NoSuchMethodException e) {
      throw new RuntimeException("Unable to find constructor for " + factoryClass.getName());

    } catch (InvocationTargetException | InstantiationException | IllegalAccessException e) {
      throw new RuntimeException(
          "Failed to construct instance from " + "constructor " + factoryClass.getName(), e);
    }
  }
}

View on GitHub (pinned to 12126d8942)