https://openjdk.java.net/ 
public interface javax.xml.xpath.XPathFunctionResolver
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: javax.xml.xpath.XPathFunctionResolver
  super_class: java.lang.Object
{
  public abstract javax.xml.xpath.XPathFunction resolveFunction(javax.xml.namespace.QName, int);
    descriptor: (Ljavax/xml/namespace/QName;I)Ljavax/xml/xpath/XPathFunction;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
              Name  Flags
      functionName  
      arity         
}
SourceFile: "XPathFunctionResolver.java"