public void setZookeeperConfig(ZookeeperConfig zookeeperConfig) {
    this.zookeeperConfig = zookeeperConfig;
  }
load( or override) priority: jvm &gt; system &gt; file(yaml, properties) &gt; classpath(yaml,
properties)

TODO(zheng): support more environment source command line &gt; jvm &gt; system &gt; jndi &gt;
file &gt; classpath
src/main/java/com/eudemon/ratelimiter/env/RateLimiterConfig.java