问题
What does it mean when the Dalvik Virtual Machine got a "Shared Constant Pool" compared to the Java Virtual Machine?
How is this a benefit and how does the Dalvik Machine achieve this?
回答1:
The Java virtual machine stores each class in an individual .class file. Each class file has a constant pool for things like strings, method names, class names, etc. If multiple classes reference the same string, then each class file will have a copy of that string in its constant pool.
The Dalvik virtual machine stores multiple classes in a single dex file, with a single constant pool. So if multiple classes reference the same string, there will only be one copy of that string in the "global" constant pool for that dex file.
The benefit is that it is more space efficient, and since dalvik memory maps these dex files into memory, it is also more memory efficient.
来源：https://stackoverflow.com/questions/16690815/shared-constant-pool