Java tutorial
//package com.java2s; import android.util.Base64; import java.nio.ByteBuffer; import java.util.UUID; public class Main { /** * Generates a Base64 version of UUID * @return a string in Base64 URL-safe format without padding at the end and no wrapping */ public static String randomUuidBase64() { UUID uuid = UUID.randomUUID(); ByteBuffer bb = ByteBuffer.wrap(new byte[16]); bb.putLong(uuid.getMostSignificantBits()); bb.putLong(uuid.getLeastSignificantBits()); return encodeUrlSafe64(bb.array()); } public static String encodeUrlSafe64(byte[] array) { int flags = Base64.NO_PADDING | Base64.NO_WRAP | Base64.URL_SAFE; return Base64.encodeToString(array, flags); } }