public CertificateTypeExtension(ExtensionType type,boolean isClient){
  super(type);
  this.isClientExtension=isClient;
  this.certificateTypes=new ArrayList<CertificateType>();
}

public CertificateTypeExtension ( ExtensionType type , boolean isClient ) { super ( type ) ; this . isClientExtension = isClient ; this . certificateTypes = new ArrayList < CertificateType > ( ) ; }
constructs an empty certificate type extension . if it is client - sided there is a list of supported certificate type ( ordered by preference ) ; server - side only 1 certificate type is chosen .
