It checks if the JQuery is active or not and wait till it is active.

ajax.java

Boolean isJqueryUsed = (Boolean)((JavascriptExecutor)driver).executeScript("return (typeof(jQuery) != 'undefined')"));
if(isJqueryUsed){
  while (true){
    // JavaScript test to verify jQuery is active or not
    Boolean ajaxIsComplete = (Boolean)(((JavascriptExecutor)driver).executeScript("return jQuery.active == 0"));
    if (ajaxIsComplete) break;
    try{
      Thread.sleep(100);
    }catch (InterruptedException e) {}
  }
}