@Override public HeadersRequestCondition combine(HeadersRequestCondition other){
  Set<HeaderExpression> set=new LinkedHashSet<>(this.expressions);
  set.addAll(other.expressions);
  return new HeadersRequestCondition(set);
}

@ Override public HeadersRequestCondition combine ( HeadersRequestCondition other ) { Set < HeaderExpression > set = new LinkedHashSet < > ( this . expressions ) ; set . addAll ( other . expressions ) ; return new HeadersRequestCondition ( set ) ; }
returns a new instance with the union of the header expressions from " this " and the " other " instance .
