Serialization Deserilization thread safety issue resolved by using FastDateFormat in Google's GSON

DateTimeSerializer.java

import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;
import org.apache.commons.lang3.time.DateFormatUtils;
import org.apache.commons.lang3.time.DateUtils;

import java.lang.reflect.Type;
import java.text.ParseException;
import java.util.Date;
public class DateTimeSerializer implements JsonSerializer<Date>, JsonDeserializer<Date> {

  private String dateFormat;

  public DateTimeSerializer(String dateFormat) {
    this.dateFormat = dateFormat;
  }

  @Override
  public JsonElement serialize(Date date, Type typeOfSrc, JsonSerializationContext context) {
    return new JsonPrimitive(DateFormatUtils.format(date, dateFormat));// uses FastDateFormat singleton
  }

  @Override
  public Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
      throws JsonParseException {
    try {
      return DateUtils.parseDate(json.getAsString(), dateFormat);
    } catch (ParseException e) {
      return null;
    }
  }
}

ThreadSafeGsonSample.java

public class MyClass {
     private static Gson gson = new GsonBuilder()
      .registerTypeAdapter(Date.class, new DateTimeSerializer("yyyy-MM-dd HH:mm:ss"))// any format is fine
      .registerTypeAdapter(java.sql.Date.class, new DateTimeSerializer("yyyy-MM-dd HH:mm:ss"))
      .create();
  
    public static String foo_serialize(Object bar) {
      return gson.toJson(bar);
    }
    public static Bar foo_deserialize(String bar) {
      return gson.fromJson(bar,Bar.class);
    }
}