question: public static String replace ( String source , String target , String replacement ) { StringBuilder sbSource = new StringBuilder ( source ) ; StringBuilder sbSourceLower = new StringBuilder ( source . toLowerCase ( ) ) ; String searchString = target . toLowerCase ( ) ; int idx = 0 ; while ( ( idx = sbSourceLower . indexOf ( searchString , idx ) ) != - 1 ) { sbSource . replace ( idx , idx + searchString . length ( ) , replacement ) ; sbSourceLower . replace ( idx , idx + searchString . length ( ) , replacement ) ; idx += replacement . length ( ) ; } sbSourceLower . setLength ( 0 ) ; sbSourceLower . trimToSize ( ) ; return sbSource . toString ( ) ; }
target:  Reemplaza todas las apariciones del string buscado con el string de reemplazo