为什么java在以下情况下返回java.util.LinkedHashMap。。。复杂的

我的代码如下

@ResponseBody 
@RequestMapping(value ="/updateAll", method=RequestMethod.POST)  
public JSONObject update( @RequestBody List<T> list){ 
    try{
        T entity = list.get(0);
        System.out.println(entity.getClass());
        dbService.update(entityName + ".update", list);
        return jsonResult(null, null, null, 0);
    }catch(Exception ex){
        return jsonResult(null, null, ex, 0);
    }
}

这将准确地打印实体名称，没有任何问题

谁能解释一下为什么会这样？我在哪里可以了解更多关于这方面的信息

/**
 /**
     * Returns the runtime class of this {@code Object}. The returned
     * {@code Class} object is the object that is locked by {@code
     * static synchronized} methods of the represented class.
     *
     * <p><b>The actual result type is {@code Class<? extends |X|>}
     * where {@code |X|} is the erasure of the static type of the
     * expression on which {@code getClass} is called.</b> For
     * example, no cast is required in this code fragment:</p>
     *
     * <p>
public final native Class<?> getClass();

*返回此{@code对象}的运行时类。返回
*{@code Class}对象是由{@code锁定的对象
*表示的类的静态同步}方法。
*
*实际的结果类型是{@code Class getClass（）；

不管引用类型是什么。方法

getClass（）

返回

运行时类

 /**
     * Returns the runtime class of this {@code Object}. The returned
     * {@code Class} object is the object that is locked by {@code
     * static synchronized} methods of the represented class.
     *
     * <p><b>The actual result type is {@code Class<? extends |X|>}
     * where {@code |X|} is the erasure of the static type of the
     * expression on which {@code getClass} is called.</b> For
     * example, no cast is required in this code fragment:</p>
     *
     * <p>
public final native Class<?> getClass();