https://openjdk.java.net/ 
public interface javax.xml.ws.handler.soap.SOAPHandler<T extends javax.xml.ws.handler.soap.SOAPMessageContext> extends javax.xml.ws.handler.Handler<T>
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: javax.xml.ws.handler.soap.SOAPHandler
  super_class: java.lang.Object
{
  public abstract java.util.Set<javax.xml.namespace.QName> getHeaders();
    descriptor: ()Ljava/util/Set;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: ()Ljava/util/Set<Ljavax/xml/namespace/QName;>;
}
Signature: <T::Ljavax/xml/ws/handler/soap/SOAPMessageContext;>Ljava/lang/Object;Ljavax/xml/ws/handler/Handler<TT;>;
SourceFile: "SOAPHandler.java"