question: public char [ ] readPassword ( String fmt , Object ... args ) { char [ ] passwd = null ; synchronized ( writeLock ) { synchronized ( readLock ) { try { echoOff = echo ( false ) ; } catch ( IOException x ) { throw new IOError ( x ) ; } IOError ioe = null ; try { if ( fmt . length ( ) != 0 ) pw . format ( fmt , args ) ; passwd = readline ( true ) ; } catch ( IOException x ) { ioe = new IOError ( x ) ; } finally { try { echoOff = echo ( true ) ; } catch ( IOException x ) { if ( ioe == null ) ioe = new IOError ( x ) ; else ioe . addSuppressed ( x ) ; } if ( ioe != null ) throw ioe ; } pw . println ( ) ; } } return passwd ; }
target:  Provides a formatted prompt, then reads a password or passphrase from the console with echoing disabled.