code: public Builder setCachePrefix(String cachePrefix) {
              this._cachePrefix = cachePrefix;
              if (_cachePrefix != null && _cachePrefix.indexOf(':') != -1) throw new IllegalArgumentException(
                      "param cacheName cannot contain ':' character.");
              return this;
          }
docs: Adds {@code cachePrefix} to the key. This ensures there are no cache
  collisions if the same EVCache app is used across multiple use cases.
  If the cache is not shared we recommend to set this to
  <code>null</code>. Default is <code>null</code>.
  
  @param cacheName.
  The cache prefix cannot contain colon (':') in it.
  @return this {@code Builder} object