How to let the HotSpot VM be in debug mode?

Question

The reason that I need the HotSpot VM be in debug mode, is that I want some JVM options, like ``` -XX:+PrintCFGFile ``` , be supported. My current JVM version is like ``` java version "1.6.0_24" OpenJDK Runtime Environment (IcedTea6 1.11.1) (suse-3.1-x86_64) OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode) ``` Do I have to install some tool/patch to achieve that? Thanks!

Accepted Answer

After searching a while, the problem looks more clear now.

The reason that I can't use the option

```
-XX:PrintCFGToFile
```

is because the JVM I used is the product version, not debug version.

I found such a website which provides the debug version of JVM. Below is the link: http://download.java.net/jdk6/6u25/promoted/b03/index.html

I have tested the version

```
jdk-6u25-ea-bin-b03-windows-i586-debug-27_feb_2011.jar
```

It works well, the option I mentioned above can be used, and an `output.cfg` file would be produced after execution of a Java program.

After installation, there would be such a series of folders `\jdk1.6.0_25\fastdebug>`. And I get the following version info:

```
java version "1.6.0_25-ea-fastdebug"
Java(TM) SE Runtime Environment (build 1.6.0_25-ea-fastdebug-b03)
Java HotSpot(TM) Client VM (build 20.0-b10-fastdebug, mixed mode)
```

How to let the HotSpot VM be in debug mode?

Solution

Problem