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Asked: 2026-05-16T04:54:15+00:00

I’d like to know which objects can be reused (in the same or different

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  1. I’d like to know which objects can be reused (in the same or different document) when using the Java API for XML processing, JAXP:

    • DocumentBuilderFactory
    • DocumentBuilder
    • XPath
    • Node
    • ErrorHandler (EDIT: I forgot that this has to be implemented in my own code, sorry)

  2. Is it recommended to cache those objects or do the JAXP implementations already cache them?

  3. Is the (re)use of those objects thread-safe?

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  1. Editorial Team

    Reuse

    In the same thread those objects can and should be reused. For example you can use the DocumentBuilder to parse multiple documents.

    Thread Safety

    DocumentBuilderFactory used to explicity state it was not thread safe, I believe this is still true:

    An implementation of the
    DocumentBuilderFactory class is NOT
    guaranteed to be thread safe. It is up
    to the user application to make sure
    about the use of the
    DocumentBuilderFactory from more than
    one thread.

    From Stack Overflow, DocumentBuilder does not appear to be thread safe either. However in Java SE 5 a reset method was added to allow you to reuse DocumentBuilders:

    XPath is not thread safe, from the Javadoc

    An XPath object is not thread-safe and
    not reentrant. In other words, it is
    the application’s responsibility to
    make sure that one XPath object is not
    used from more than one thread at any
    given time, and while the evaluate
    method is invoked, applications may
    not recursively call the evaluate
    method.

    Node is not thread safe, from Xerces website

    Is Xerces DOM implementation
    thread-safe? No. DOM does not
    require implementations to be thread
    safe. If you need to access the DOM
    from multiple threads, you are
    required to add the appropriate locks
    to your application code.

    ErrorHandler is an interface, so it is up to your implementation of that interface to ensure thread-safety. For pointers on thread-safety you could start here:

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