Java 内存限制 -Xmx 后缀：大写与小写 m/M 和 g/G
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Java Memory Limit -Xmx suffix: upper vs lower case m/M and g/G
提问by MinecraftShamrock
It is commonly known that it is possible to limit the Java heap size with -Xmx<amount><unit>, where unitis the data amount unit like Gigabyte, Megabyte, etc.
I know that -Xmx128Mmeans 128 Mebibytes (= 128 * 1024 * 1024 bytes).
众所周知，可以使用 来限制 Java 堆大小-Xmx<amount><unit>，其中unit数据量单位是千兆字节、兆字节等。我知道这-Xmx128M意味着 128兆字节（= 128 * 1024 * 1024 字节）。
But is it true, that it is also possible to use decimal units like megabytes using -Xmx100m(which would be 100 * 1000 * 1000 bytes)?
但是真的-Xmx100m吗，也可以使用像兆字节这样的十进制单位（即 100 * 1000 * 1000 字节）？
So is it possible to use this decimal units by using lower-case unit suffixes like k, m, ginstead of K, M, G?
那么是否可以通过使用小写单位后缀k, m, g而不是K, M, G?
采纳答案by Sanjeev
There is no difference between k and K both means kibibyteand so does m/M = mebibyte& g/G = gibibyte. you can set 100mas the value and it will be 100 * 1024 * 1024 bytes. generally it is advised to use this value in powers of 2.
k 和 K 之间没有区别，kibibytem/M = mebibyte& g/G = 也是如此gibibyte。您可以设置100m为值，它将是100 * 1024 * 1024 bytes. 通常建议在powers of 2.
Hope it helps.
希望能帮助到你。
回答by apangin
Why don't you just try -Xmx100mand -Xmx100Mand check if there is any difference.k, m, gwork exactly like K, M, G- they all mean binary units.
你为什么不尝试-Xmx100m并-Xmx100M检查是否有任何区别。k, m, g工作方式完全一样K, M, G——它们都是二进制单位。
回答by TerekC
All memory sizes used by the JVM command line arguments are specified in binary units (Kibibyte, Mebibyte, etc.) regardless of unit capitalization; where a 'kilobyte' is 1024 bytes, and the others are increasing powers of 1024.
JVM 命令行参数使用的所有内存大小均以二进制单位（Kibibyte、Mebibyte 等）指定，而不管单位大小写；其中“千字节”为 1024 字节，其他为 1024 的递增幂。
This answergoes into a more complete technical answer to the question.
这个答案是对这个问题的更完整的技术答案。
