This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
u can use setEchochar method of text field for this purpose.
public void setEchoChar(char c) Sets the echo character for this text field. An echo character is useful for text fields where user input should not be echoed to the screen, as in the case of a text field for entering a password. Setting echoChar = 0 allows user input to be echoed to the screen again.