java问题

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学习过程中遇到的一些技术问题。

String interning

String interning keeps every String only once in memory.

https://en.wikipedia.org/wiki/String_interning

关于java程序种的内存

Total designated memory, this will equal the configured -Xmx value: Runtime.getRuntime().maxMemory();

Current allocated free memory, is the current allocated space ready for new objects. Caution this is not the total free available memory: Runtime.getRuntime().freeMemory();

Total allocated memory, is the total allocated space reserved for the java process: Runtime.getRuntime().totalMemory();

Used memory, has to be calculated:

usedMemory = Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();

Total free memory, has to be calculated: freeMemory = Runtime.getRuntime().maxMemory() - usedMemory;

如图所示：

参考链接：

https://stackoverflow.com/questions/3571203/what-are-runtime-getruntime-totalmemory-and-freememory