ph-schematron/src/main/java/com/helger/schematron/pure/bound/xpath/PSXPathBoundSchema.java
@Nullable
  private static XPathExpression _compileXPath (@Nonnull final XPath aXPathContext,
                                                @Nonnull final String sXPathExpression) throws XPathExpressionException
  {
    XPathExpression ret = null;
    try
    {
      ret = aXPathContext.compile (sXPathExpression);
    }
    catch (final XPathExpressionException ex)
    {
      // Do something with it
      throw ex;
    }
    return ret;
  }
@Nullable
  private static XPathExpression _compileXPath (@Nonnull final XPath aXPathContext,
                                                @Nonnull final String sXPathExpression) throws XPathExpressionException
  {
    XPathExpression ret = null;
    try
    {
      ret = aXPathContext.compile (sXPathExpression);
    }
    catch (final XPathExpressionException ex)
    {
      // Do something with it
      throw ex;
    }
    return ret;
  }
Compile an XPath expression string to an {@link XPathExpressionException}
object. If expression contains any variables, the
{@link XPathVariableResolver} will be used to resolve them within this
method!

@param aXPathContext
Context to use. May not be <code>null</code>.
@param sXPathExpression
The expression to be compiled. May not be <code>null</code>.
@return The precompiled {@link XPathExpression}
@throws XPathExpressionException
If expression cannot be compiled.