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POjstack output - get tid for java Thread.getId
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  1. POjstack output - get tid for java Thread.getId
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    copied!<p>I had a look at existing questions on getting the thread id like <a href="https://stackoverflow.com/questions/222108/getting-the-java-thread-id-and-stack-trace-of-run-away-java-thread">java-thread-id-and-stack-trace </a>.</p> <p>But I'm not able to figure out something that seemed simple. I want to make a JSP tool to stop a thread in Java.</p> <p>I know it's a bad idea in general but we need it as we can't use JConsole in our environment cause some hardening of JBoss.</p> <p>My questions are, take a sample jstack output:</p> <ol> <li><code>Event Batch Processing (Spring UAA/1.0.2)" daemon prio=10 tid=0x0000000041e27800 nid=0x363b waiting on condition [0x00007f9a89267000]</code> From this which id would be the <code>thread.getId()</code> as defined in <code>java.lang.Thread</code>? What is the last token in this line <code>[0x00007f9a89267000]</code>?</li> <li>How do I convert (Java code would be super) the <code>hex</code> to a Java <code>long</code>? </li> <li><p>Could you tell me why this did not work -> I took a hex <code>tid=</code> from a jstack of a thread that was hung in a never ending loop. I then did this:</p> <pre><code>Thread thrd = null; String thrdId =request.getParameter("thrd"); if(thrdId != null){ out.print("thread " + thrdId + " :"); out.flush(); Map&lt;Thread,StackTraceElement[]&gt; map = Thread.getAllStackTraces(); Set tt = map.keySet(); Iterator&lt;Thread&gt; ti = tt.iterator(); try{ long idFind = Long.parseLong(thrdId); out.print("&lt;br&gt; idFind thread |" + idFind + "| &lt;br&gt;"); boolean found = false; while(ti.hasNext() ){ thrd = ti.next(); if(thrd.getId() == idFind){ out.print("&lt;br&gt; stopping thread " + thrd + " &lt;br&gt;"); out.flush(); thrd.stop(); out.print("&lt;br&gt;stopped " ); found = true; break; } } if(!found){ out.print("&lt;br&gt;not found " ); } }catch(Exception e){ out.println("&lt;br&gt;err " + e + "&lt;br&gt;"); } } </code></pre></li> </ol> <p>Output of this was not found. The input param was the tid - pasted in Windows 7 calc, Programmer mode (hex) and then clicked Dec.</p> <p><strong>UPDATE:</strong></p> <p>In my test code when I made a JSP that loops infinitely, outputting a char every few 10000s iterations - then did a jstack, got:</p> <pre><code>"http-0.0.0.0-8181-4" daemon prio=6 tid=0x000000000d4eb000 nid=0x2f58 waiting on condition [0x0000000010fee000] java.lang.Thread.State: TIMED_WAITING (sleeping) ...(stack trace) at org.apache.jsp.t.testing.loop_jsp._jspService(loop_jsp.java ...more stack trace... </code></pre> <p>I ran jstack a few times and get this entry every time.</p> <p>But when I run my JSP with thread <code>id = 000000000d4eb000</code>, it cant find it, since the app container names threads uniquely I was able to find the thread and when I print: </p> <pre><code>out.print("" + cnt + " \"" + thrd.getName() + "\"| id :" + thrd.getId() + "| hex :" + Long.toHexString(thrd.getId()) + "| &lt;br&gt;"); </code></pre> <p>I get :</p> <pre><code>93 "http-0.0.0.0-8181-4"| id :1389| hex :56d| 93 is the thread number in my internal counter in the loop. </code></pre> <p>So what jstack apparently identifies as finds as <code>0x000000000d4eb000</code> internal JVM knows as <code>1389 hex :56d</code>? Finally changed the JSP to search by name and stop the thread. lucky the thread names are all different. But is this a bug - running Windows, JBoss 4.2, Java 1.6 update 32?</p>
 

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