Given the code fragment: Which method should be used on line 3 to enable default validation mechanism?

Question

Options

• Au.setProperty(String, Object)
• Bu.setProperty(Schema)
• Cu.setEventHandler(ValidationEventHandler)
• Du.setAdapter(XmlAdapter)

• A
  7% (3)
• C
  5% (2)
• D
  88% (37)

Explanation

Note: This question appears to have a potentially incorrect answer key. Based on standard JAXB (javax.xml.bind) APIs, setAdapter(XmlAdapter) is used for custom type binding/conversion, not for enabling validation. The method that actually enables default XML validation in JAXB is setSchema(Schema) on the Unmarshaller - closest to option B, though B's signature is wrong (setProperty(Schema) doesn't exist). This looks like a flawed exam question common in some Java certification prep materials.

That said, here's how the options break down:

• A - setProperty(String, Object) sets implementation-specific properties (like JAXB_ENCODING), not validation.
• B - setProperty(Schema) doesn't exist as a method; the real validation method is setSchema(Schema), making this a distractor using a plausible-but-wrong signature.
• C - setEventHandler(ValidationEventHandler) installs a listener for validation events but doesn't itself enable validation.
• D - setAdapter(XmlAdapter) registers a custom type adapter for data conversion, unrelated to validation.

For the exam: If your prep material marks D as correct, memorize it as-is. But if you encounter a real JAXB question on production certification exams (OCP), know that unmarshaller.setSchema(schema) is the genuine way to enable schema-based validation.

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