question: public TrustManagerBuilder add ( TrustManager ... mgrs ) { for ( TrustManager tm : mgrs ) { if ( tm instanceof X509TrustManager ) { mgr . add ( ( X509TrustManager ) tm ) ; } } return ( this ) ; }
target:  Use this to add arbitrary TrustManagers to the mix. Only the X509TrustManager instances in the array will be used. This is also used, under the covers, by most of the other builder methods, to add configured trust managers.