question: public void put ( String id , String str ) { tab . put ( id , str ) ; if ( str . endsWith ( ".dtd" ) ) { int i = str . lastIndexOf ( File . separator ) ; if ( i >= 0 ) { tab . put ( str . substring ( i + 1 , str . length ( ) - 4 ) , str ) ; } } }
target:  Add a mapping from a public identifier to a path.