The stray double quote is not coming form this line:

htmlBuf.append("<CENTER><IMG SRC=http://localhost:8080/dirx/servlets");

but from this one
      htmlBuf.append("\" USEMAP=\"#expression\" BORDER=\"0
----------------------^^
which has the escaped quote just there. You can fix this by amending the
first line as follows, from

htmlBuf.append("<CENTER><IMG SRC=http://localhost:8080/dirx/servlets");
// to
htmlBuf.append("<CENTER><IMG SRC=\"http://localhost:8080/dirx/servlets");

---------------------------------^^

or removing the escaped quote as follows from:

      htmlBuf.append("\" USEMAP=\"#expression\" BORDER=\"0		//
to
      htmlBuf.append(" USEMAP=\"#expression\" BORDER=\"0               
----------------------^ // missing quote here

chanoch