Question

英文好的大哥帮忙翻译一下啊！！！

14.2.2. Dynamic Transformation
Dynamic transformation operates at some time between the JVM request for a class and the loading of that class. Dynamic transformation may occur at the server as specific clients request the class, at an intermediate proxy that transforms classes as they pass through the network [17], or at load time as the classes enter the JVM.
The classloader architecture provided in Java provides a convenient mechanism to alter the semantics of loading a class. A classloader is a user-defined object in Java responsible for locating and obtaining classfiles and handing them to the JVM. While classloaders are intended to enable programmers to control the source location or time of class, they also provide an opportunity for transformation.
Performing the transformation at load time is the only way to guarantee transformation of foreign code, such as applets or servlets loaded from the network. It can apply whole-program transformations to such applications.
In addition to ensuring that every application class supports a given feature, a transformation can also be restrictive, guaranteeing that no application class uses a forbidden feature. For example, a restrictive transformer can limit access to a secure resource by simply disallowing any code that references that resource. The transformer can then safely add its own calls to that resource. Given Java's type-safety, all calls to that resource are guaranteed to be legitimate. (However, see the discussion later on reflection).
Load-time transformation is incremental: The transformer processes individual classes one at a time as they are loaded. The transformer does not control the load order of the classes, and most current JVMs do not allow modification or reloading of already-loaded classes. Transformers thus have only one chance to transform classes and often must do so with incomplete information about the entire application.
This constraint limits the applications for load-time transformation. For example, a dynamic transformer cannot, in general, apply optimizations requiring interprocedural analysis (such as leaf method removal) because the transformation may operate on a call site before the matching method is loaded. Transformer control over the class load order would improve the generality of dynamic transformation but would not solve the problem. For method invocations for which the transformer cannot determine the run-time type of the object, the classloader would require all possible descendents of that object to determine the safety of that method invocation. The current specification of the classfile does not provide that information, and in general, new subclasses may dynamically appear.

Answer 1

14.2.2 。动态转化
动态转化运转一段时间之间的JVM请求为工人阶级和载货一班。动态转化，可发生于服务器作为特定客户要求的阶级，在一个中间代理，能变换班级，因为他们通过网络[ 17 ] ，或在负荷时间为班级进入JVM的。
本类建筑提供了在Java中提供了一个方便的机制，以改变语义装载一类。一类是一个用户定义的对象，在华负责寻找和获取classfiles并移交给JVM的。而classloaders目的是为了让程序员控制源头地点或时间的阶级，他们也提供一个机会转型。
演艺改造，在负荷时间是唯一的出路，以保证改造的外国代码，如应用程序或servlet是由负载网络。它可以适用于整个程序转变为这类申请。
此外，以确保每一个应用类支持某一特定功能，转型也可以限制，也保证不应用类使用禁忌特征。举例来说，一个限制性变压器可以限制进入到一个安全可靠的资源，由单纯不准任何代码，参考资源。变压器便可以安全地放入自己的通话资源。由于Java的类型安全，所有来电，资源有保证，以合法的。 （不过，看到讨论后，就思考） 。
载荷-时间转型是增量：变压器过程中的个别班级一个在一个时间，因为他们已经上膛。变压器并不控制负荷秩序的班，目前大多数jvms不容许修改或重新装载已经加载班。变压器，因此只有一个机会变换班级，往往必须这样做，不完全信息对整个应用。
这一约束限制了申请载荷-时间转型。举例来说，一个充满活力的变压器不能外，一般适用于优化需要跨过程分析（如叶片法去除） ，因为改造，可经营呼唤工地前匹配方法加载。变压器控制班级负荷秩序会改善的一般性的动态转化，但不会解决这个问题。为方法调用，其中变压器不能确定的运行时类型的对象，类将要求所有可能的后裔，那个对象，以确定安全性表示方法调用。目前规格的classfile不提供这方面的资料，并在总体上，新的子类，可动态地出现.

唉!很辛苦翻译下来.优美追加分可拿?

Answer 2

内容太多，给的分又太少，哎，实在不想看。

Answer 3

太多了,眼花缭乱~~~

Answer 4

太长了,你还是用英语翻译软件试试吧...............