java-毕业论文外文文献翻译.doc

Advantages of Managed Code Microsoft intermediate language shares with Java byte code the idea that it is a low-level language with a simple syntax , which can be very quickly translated into native machine code. Having this well-defined universal syntax for code has significant advantages. Platform independence First, it means that the same file containing byte code instructions can be placed on any platform; at runtime the final stage of compilation can then be easily accomplished so that the code will run on that particular platform. In other words, by compiling to IL we obtain platform independence for .NET, in much the same way as compiling to Java byte code gives Java platform independence. Performance improvement IL is actually a bit more ambitious than Java byte code. IL is always Just-In-Time compiled (known as JIT), whereas Java byte code was often interpreted. One of the disadvantages of Java was that, on execution, the process of translating from Java byte code to native executable resulted in a loss of performance. Instead of compiling the entire application in one go (which could lead to a slow start-up time), the JIT compiler simply compiles each portion of code as it is called (just-in-time). When code has been compiled.once, the resultant native executable is stored until the application exits, so that it does not need to be recompiled the next time that portion of code is run. Microsoft argues that this process is more efficient than compiling the entire application code at the start, because of the likelihood that large portions of any application code will not actually be executed in any given run. Using the JIT compiler, such code will never be compiled. This explains why we can expect that execution of managed IL code will be almost as fast as executing native machine code. What it doesn’t explain is why Microsoft expects that we will get a performance improvement. The reason given for this is that, since the final stage of compilation takes p