code: public void setCrossDomainMappings(Map newCrossDomainMappings) {
          Assert.notNull(newCrossDomainMappings, "A valid list of HTTPS cross domain name mappings must be provided");
  
          crossDomainMappings.clear();
  
          Iterator it = newCrossDomainMappings.entrySet().iterator();
  
          while (it.hasNext()) {
              Map.Entry entry = (Map.Entry) it.next();
              crossDomainMappings.put((String) entry.getKey(), (String) entry.getValue());
          }
  
          if (crossDomainMappings.size() < 1) {
              throw new IllegalArgumentException("must map at least one cross domain name");
          }
      }
docs: Set to map the cross domain respectively to port mappings defined in the {@link PortMapper}
  In a Spring XML ApplicationContext, a definition would look something like this:
  <pre>
  &lt;property name="crossDomainMappings">
  &lt;map>
  &lt;entry key="company.com">&lt;value>sso.company.com&lt;/value>&lt;/entry>
  &lt;entry key="internal.company.com">&lt;value>auth.internal.company.com&lt;/value>&lt;/entry>
  &lt;/map>
  &lt;/property></pre>
  
  @param newCrossDomainMappings - A Map consisting of String keys and String values, where for each entry the key is the string
  representation of an HTTP cross domain, and the value is the string representation of the corresponding integer HTTPS cross domain.
  
  @throws IllegalArgumentException if input map does not consist of String keys and values.