question: boolean alias ( String src , String target ) { if ( src == null ) return false ; PluginHolder < T > a = registry . get ( src ) ; if ( a == null ) return false ; PluginHolder < T > b = registry . get ( target ) ; if ( b != null ) return false ; registry . put ( target , a ) ; return true ; }
target:  make a plugin available in an alternate name. This is an internal API and not for public use