Java

已检查的异常 类型擦除 缺少操作符重载(例如BigInteger/BigDecimal) 缺少regexp/date/duration /复杂文字 对不可变性的支持很差

C#.

我最讨厌的是:

No multiple inheritance - imagine you could provide whatever GUI framework base class (Control, Window, whatever) with MVC - related stuff, etc... framework / base class agnostic! No "friend" keyword... I know, the RAD - victims would abuse it for all kinds of stinky code and for hilarious malpractices, but it would be nice for the OOD - guys to enforce the law of demeter No language integrated DBC features, there are the Contracts, but I would rather have that Spec# - style with a general purpose "!" - postfix operator No AOP (I don't get it... this language has attributes, it would have been SO EASY to add interception code in the compiler!) No weak event delegates - the observer pattern becomes nothing but a memory leak bait as it is now... :-(

Python:

No standard GUI toolkit (the community goes round and round about this but never seems to settle on anything). The evolution of tools and methods to distribute and install Python apps and libraries has been, well, rocky. (Although lately this seems to be moving closer to getting fixed.) CPython is still slow as interpreters go (although PyPy is looking pretty good these days, if it becomes the "standard" Python this problem goes away). You can't subclass built-in classes (e.g., list and dict) without overriding a lot of methods, even if all you want to do is a simple hook into an event (e.g., to hook into an item being added to or removed from the list, you need to override delitem, append, extend, insert, pop, and remove--there's no subclassable "change" event notification, nor any "protected" methods that factor out common code used by all the above methods). Up until virtualenv was invented, keeping separate Python environments for different purposes on one machine was a real pain.

Lua:

元表是如此令人困惑，直到他们“点击” 缺少像a += 20这样的赋值操作符是一种痛苦 没有集成的面向对象的解决方案意味着每个人和他的狗都使用自己的口味 用于注释(——)的语法排除了加/减前后操作符的可能性 不入侵C端就不可能有任何先发制人的多任务系统

Lua:

The built-in error system is absolutely horrendous You can implement a try-catch system by modifying the Lua interpreter; but it has no compatibility with the errors that are thrown by the built in functions. The fact they have __newindex instead of __setindex as the setter ... and __newindex is only fired when the key doesn't already exist. If it does, no metamethod is called at all. No good type comparison system. There's the type() function but it only handles the basic types (all tables are tables). It really needs to have a metamethod for type comparisons. I've implemented this before with an 'is' operator and a __type metamethod and it works really nicely. It's a bitch to define new keywords. You can do it, but the code inside Lua isn't well documented so it's kind of trial and error to find out how to get the result you want. This is a major issue when you want to implement the things I mentioned above yourself (not so much __setindex though, that's an easy modification). I can't use it in a web browser. Yeah not really a problem with the language itself, but damn, would I love to be able to use Lua instead of Javascript... :)

length属性很容易与length()函数混淆;请改用size() 在选择器字符串中插入变量的语法('" +$。Month + "')臭死了 $(event.currentTarget)并不总是适用于冒泡和捕获 属性语法("[class='foot']")在选择器语法(".foot")不返回任何结果的地方起作用 包含选择器([class~=done])有时会在JavaScript (this.className.search("done") > 0)工作时失败