Here you can find the source of generateContentID()
public static String generateContentID()
//package com.java2s; import java.util.UUID; public class Main { /**//from w w w.j av a 2 s. c om * Calls {@link #generateContentIDFromAddrSpec(String)} with * {@link #generateRFC822AddrSpec()} as parameter. * * @return the generated Content-ID */ public static String generateContentID() { return generateContentIDFromAddrSpec(generateRFC822AddrSpec()); } /** * Helper method to generate a standards-compliant Content-ID header value * from the supplied addrSpec. * * Used rfc-s: RFC2045, RFC822 * * @return the generated Content-ID */ public static String generateContentIDFromAddrSpec(String addrSpec) { return "<" + addrSpec + ">"; } /** * Helper method to generate a standards-compliant, random addr-spec as * described in RFC822. * * @return the generated addrSpec */ public static String generateRFC822AddrSpec() { return UUID.randomUUID().toString() + "@resteasy-multipart"; } }