In the JAVA program, a 6-bit verification code (composed of 0-9a-ZA-Z) is randomly generated. Ask the expert to help, thank you.

Common string get () {stringstr = ""; for(int I = 0； I<6; i++){ int itmp = random . nextint(26)+65； char ctmp =(char)itmp； str+= ctmp； } return str}