java 我如何知道为 Sun JVM 启用了哪些默认设置？
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How do i know which default settings are enabled for Sun JVM?
提问by Janning
i want to try CompressedOops on my JVM. No I wonder if it might be enabled by default. I run this jvm on debian/squeeze:
我想在我的 JVM 上尝试 CompressedOops。不，我想知道它是否可能默认启用。我在 debian/squeeze 上运行这个 jvm：
$ java -version
java version "1.6.0_22"
Java(TM) SE Runtime Environment (build 1.6.0_22-b04)
Java HotSpot(TM) 64-Bit Server VM (build 17.1-b03, mixed mode)
Some people say it is enabled by default, some say it is not:
有人说它默认启用，有人说它不是：
from: http://forums.yourkit.com/viewtopic.php?f=3&t=3185
来自：http: //forums.yourkit.com/viewtopic.php?f=3&t=3185
Yes, you are right, I also checked it and Compressed Oops is not activated by default in Java6u21 64-bit, I do not understand why it said so in the links I provided.
是的，你是对的，我也检查过，在 Java6u21 64 位中默认没有激活压缩的 Oops，我不明白为什么在我提供的链接中这么说。
I tried to check it with jconsole/JMX but had no luck to find an attribute named CompressedOops or alike.
我试图用 jconsole/JMX 检查它，但没有找到一个名为 CompressedOops 或类似的属性。
Does anybody know where i get a list of all jvm options for a specific build with their default values?
有谁知道我在哪里获得特定构建的所有 jvm 选项及其默认值的列表？
regards Janning
问候詹宁
回答by staffan
You can run with -XX:+PrintFlagsFinalto print the values of all flags at startup of the JVM.
您可以-XX:+PrintFlagsFinal在 JVM 启动时运行 with打印所有标志的值。
Alternatively, you can use the jinfotool to check the value of a flag in a running JVM:
或者，您可以使用该jinfo工具检查正在运行的 JVM 中标志的值：
> jinfo -flag UseCompressedOops 7364
-XX:+UseCompressedOops
Use jpsto find the pid of the process.
使用jps查找进程的PID。
