在Java中， -Xms设置初始Java堆大小，而-Xmx设置最大Java堆大小。

1.一些java -Xms -Xmx示例：

# Start with 128MB of memory, and allow the Java process to use up to 1024MB of memory.
java -Xms128m -Xmx1024m

# Start with 256MB of memory, and allow the Java process to use up to 4G (4096MB) of memory.
java -Xms256m -Xmx4g

2.默认的初始和最大Java堆大小是根据这种人体工程学算法分配的，还请阅读本文– 查找Java堆内存大小

3.如果Java进程超出了-Xmx最大Java堆大小，则将引发流行的java.lang.OutOfMemoryError 。

4.对于其他选项，请运行此java -X

> java -X-Xbatch           disable background compilation-Xbootclasspath/a:<directories and zip/jar files separated by ;>append to end of bootstrap class path-Xcheck:jni       perform additional checks for JNI functions-Xcomp            forces compilation of methods on first invocation-Xdebug           provided for backward compatibility-Xdiag            show additional diagnostic messages-Xfuture          enable strictest checks, anticipating future default-Xint             interpreted mode execution only-Xinternalversiondisplays more detailed JVM version information than the-version option-Xloggc:<file>    log GC status to a file with time stamps-Xmixed           mixed mode execution (default)-Xmn<size>        sets the initial and maximum size (in bytes) of the heapfor the young generation (nursery)-Xms<size>        set initial Java heap size-Xmx<size>        set maximum Java heap size-Xnoclassgc       disable class garbage collection-Xrs              reduce use of OS signals by Java/VM (see documentation)-Xshare:auto      use shared class data if possible (default)-Xshare:off       do not attempt to use shared class data-Xshare:on        require using shared class data, otherwise fail.-XshowSettings    show all settings and continue-XshowSettings:allshow all settings and continue-XshowSettings:localeshow all locale related settings and continue-XshowSettings:propertiesshow all property settings and continue-XshowSettings:vmshow all vm related settings and continue-XshowSettings:system(Linux Only) show host system or containerconfiguration and continue-Xss<size>        set java thread stack size-Xverify          sets the mode of the bytecode verifier

参考文献

• 调整Java虚拟机（JVM）
• Eclipse -Xms / -Xmx
• 人机工程学算法
• 找出您的Java堆内存大小

翻译自: https://mkyong.com/java/java-what-is-xms-and-xmx-parameter/