如何在不删除电子邮件的情况下删除Gmail附件？(How Remove Gmail Attachments In Place Without Deleting Email?)

 
 
 是本地代码汇编语言？ 
 
 
 汇编语言是编写代码的一种方式， 汇编程序将汇编成机器代码，这就是写入可执行文件等的代码。 也就是说，汇编代码是人类的源代码，仅处于非常低的水平; 机器码是在该源代码上运行汇编程序的结果。 （这与您编写像C ++这样的更高级语言并使用编译器将其编译为机器代码相似。） 
 
 
 
 jvm究竟做了什么，通过编码和解释为本地代码 
 
 
 可以编写JVM来解释字节码，但现代JVM不这么做; 他们有一个内置的即时编译器 （JIT），它可以获取字节码，并将其实时组装到机器代码中。 实际上，Sun的JVM有两阶段的JIT：一个阶段运行速度非常快（因此应用程序和类在运行时快速转换为机器代码，以避免启动延迟），另一个阶段是启动优化，它在代码中标识“热点”（代码运行很多）时使用（以便性能关键代码可以快速运行）。 
 
 所以现代JVM从.class文件中读取字节码，通过JIT运行它将其编译为机器码，并使计算机运行该机器码。 在这样做的时候，一个好的监测热点并积极地优化它们，创建更有效的新的替代机器代码。 

 
 
is native code assembly language?
 
 
Assembly language is a way of writing code that will be assembled (by an assembler) into machine code, which is what is written to executable files and such. That is, assembly code is source code for humans, just at a very low level; machine code is the result of running an assembler on that source code. (This is analogous to when you write a higher-level language like C++ and compile it to machine code with a compiler.)
 
 
 
what does exactly jvm do takes bytycode and interpret to native code
 
 
A JVM could be written that just interpreted bytecode, but modern JVMs don't do that; they have a built-in Just-In-Time Compiler (JIT) which takes the bytecode and, effectively, assembles it on the-fly into machine code. In fact, Sun's JVM has a two-stage JIT: One stage that runs really quickly (so apps and classes get converted to machine code quickly when run, to avoid startup delays), and another stage it kicks in that does aggressive optimization, which it uses when it identifies "hot spots" (code that runs a lot) in the code (so that performance-critical code runs quickly).
 
So modern JVMs read bytecode from .class files, run it through the JIT to compile it to machine code, and have the computer run that machine code. While doing that, a good one monitors hot spots and aggressively optimizes them, creating new, replacement machine code that's more efficient.