-XX
標準選擇（Standard Options）
These are the most commonly used options that are supported by all implementations of the JVM.

示例：

-XX:+UseConcMarkSweepGC
-XX:+CMSParallelRemarkEnable
-XX:+UseFastAccessorMethods

-X
非標準選擇（Non-Standard Options）
These options are general purpose options that are specific to the Java HotSpot Virtual Machine.

示例：

-Xmx256m
-Xms256m
-Xmn768m
-Xss256k

-D
設定系統屬性值（Sets a system property value）
-D屬性名稱=屬性值
Sets a system property value. The property variable is a string with no spaces that represents the name of the property.
The value variable is a string that represents the value of the property. If value is a string with spaces, then enclose it in quotation marks (for example -Dfoo="foo bar").

示例：

-Dspring.profiles.active=release
-Dspring.config.location=/opt/app/conf/

* 如果屬性值中間有空格，需要用雙引號括住，例如-Dclotho="clotho property value"

在IDEA中通過Run/Debug configurations中的VM.options配置

* 如果預設沒顯示，可點選Build and run右邊的Modify options -> Java -> Add VM options