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copied!<p>This is an answer to the secondary question, "How can you tell if the -XstartOnFirstThread argument is actually being read by the VM?" (or the related question, "how can you detect if -XstartOnFirstThread was passed to the VM?") I looked at <code>java.lang.management.RuntimeMXBean.getInputArguments()</code>, but <code>-XstartOnFirstThread</code> is <em>not</em> included in the returned <code>List</code>. After some research, I was able to figure out something, so I hope this helps someone else who was in my shoes.</p> <p>According to <a href="http://bugs.sun.com/view_bug.do?bug_id=7131021" rel="nofollow">this link</a>, there are several environment variables set by the launcher. Among them are: <code><pre>JAVA_MAIN_CLASS_<em>pid</em> JAVA_STARTED_ON_FIRST_THREAD_<em>pid</em></pre></code></p> <p>Use <code>System.getenv()</code> to obtain a <code>Map</code> of the environment variables. From there, you can iterate through the <code>entrySet()</code> until you find an <code>Entry</code> with a <code>getKey()</code> whose return value starts with <code>"JAVA_MAIN_CLASS_"</code> . If the discovered <code>Entry</code>'s <code>getValue()</code> contains the name of your main class, you can use the rest of the key to determine the <em>pid</em>.</p> <p>Once you have the <em>pid</em>, look up the string <code>"JAVA_STARTED_ON_FIRST_THREAD_<em>pid</em>"</code> in the environment <code>Map</code>. If it exists and has the value <code>"1"</code>, the process was started with <code>-XstartOnFirstThread</code>. Otherwise, the process was started without the flag.</p> <p>This probably won't work in an unsigned WebStart application, since the <code>System.getenv()</code> method is prohibited by default. But in a signed webstart application, or in a regular Java application, this does work.</p> <p>Hope that helps,</p>

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