wro4j-core/src/main/java/ro/isdc/wro/model/resource/processor/factory/ConfigurableProcessorsFactory.java
private Map<String, ResourcePostProcessor> getPostProcessorsMap() {
    if (this.postProcessorsMap == null) {
      synchronized (this) {
        if (this.postProcessorsMap == null) {
          this.postProcessorsMap = newPostProcessorsMap();
        }
      }
    }
    return this.postProcessorsMap;
  }
private Map<String, ResourcePostProcessor> getPostProcessorsMap() {
    if (this.postProcessorsMap == null) {
      synchronized (this) {
        if (this.postProcessorsMap == null) {
          this.postProcessorsMap = newPostProcessorsMap();
        }
      }
    }
    return this.postProcessorsMap;
  }
To be used for internal usage. Ensure that returned object is not null.