This project formats JVM info as simple text. It works well as a zero-configuration debugging tool for web-based applications.
There are no classpath dependencies; all utility classes are included and package private.
Direct instantiation:
import com.widen.util.td.ThreadDumpServlet;
JvmThreadDump out = new JvmThreadDump();
String dump = out.generate();
System.out.println(dump);
Servlet configuration:
<web-app>
<servlet>
<servlet-name>threaddump</servlet-name>
<servlet-class>com.widen.util.td.ThreadDumpServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>threaddump</servlet-name>
<url-pattern>/td</url-pattern>
</servlet-mapping>
</web-app>
Overridable methods for customization:
List<String> getMainArguments()- The default method returns an empty list.
Map<String, Object> getCustomValues()- Useful if you have environment specific information to aid in debugging the application.
String.valueOf(...)is used to generate a text representation of the value Object.
The supplied servlet does not support using a custom JvmThreadDump class. We recommend that you copy ThreadDumpServlet.java into your source tree and modify as required.
public class MyAppThreadDumpServlet extends HttpServlet
{
private final String appName;
private final AppEnvironment env;
public ThreadDumpServlet(String appName, AppEnvironment env)
{
this.appName = appName;
this.env = env;
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
Map<String, Object> map = Maps.newHashMap();
map.put("App", appName);
map.put("Environment", env);
JvmThreadDump dump = new MyAppThreadDump(map);
String out = dump.generate();
resp.setContentType("text/plain");
resp.setContentLength(out.length());
resp.setHeader("Cache-Control", "no-cache, no-store, must-revalidate, max-age=0");
resp.setHeader("Expires", "Thu, 01 Jan 1970 12:00:00 +0000");
resp.setHeader("X-Accel-Expires", "off");
resp.setHeader("X-Robots-Tag", "noindex, nofollow");
PrintWriter writer = resp.getWriter();
writer.write(out);
}
private static class MyAppThreadDump extends JvmThreadDump
{
private Map<String, String> map;
public MyAppThreadDump(Map<String, String> map)
{
this.map = map;
}
@Override
protected List<String> getMainArguments()
{
return Splitter.on(" ").splitToList(System.getProperty("app.main-args", ""));
}
@Override
protected Map<String, Object> getCustomValues()
{
return map;
}
}
}
Hostname:System.getenv('HOSTNAME')CPU Load: System, JVMSystem Uptime: Linux only; parsed from file/proc/uptimeMain Arguments: Will be empty unless you override and implementgetMainArguments().
Current Time: 01/30/2019 11:18:17 CST
Default Time Zone: Central Standard Time (America/Chicago)
Java Version: 1.8.0_191-b12 (Oracle Corporation)
Java VM: 25.191-b12 (mixed mode)
Java Home: /Library/Java/JavaVirtualMachines/jdk1.8.0_191.jdk/Contents/Home/jre
Working Directory: /Users/uriah/dev/github/jvm-threaddump/generator
Temp Directory: /var/folders/ws/ydsf0xgn6mn849zk7rp25fgxl7sq5r/T/
Main Arguments:
Default Encoding: UTF-8
JVM System Props: file.encoding=UTF-8
idea.test.cyclic.buffer.size=1048576
Hostname: Not Available
Operating System: Mac OS X (10.14.2)
System Processors: 12 x86_64
System Memory: 2,017 MB available; 32,768 MB total
CPU Load: 0.0000 system; 0.0000 jvm
System Uptime: Not Available
System Idle Time: Not Available
JVM Uptime: 0 days, 0:00:00
JVM CPU Time: 0 days, 0:00:00
JVM Free Memory: 232 MB (of committed)
JVM Maximum Heap: 245 MB
JVM Memory Args: -Xmx256m
Memory: used/max
Heap: 5%/5% init=256 MB used=12 MB commit=245 MB max=245 MB
Non Heap: 93%/0% init=2 MB used=9 MB commit=10 MB max=-1 bytes
Collector: used/max
PS Eden Space: 20%/20% init=64 MB used=12 MB commit=64 MB max=64 MB
PS Survivor Space: 0%/0% init=10 MB used=0 bytes commit=10 MB max=10 MB
PS Old Gen: 0%/0% init=171 MB used=0 bytes commit=171 MB max=171 MB
Code Cache: 88%/1% init=2 MB used=2 MB commit=2 MB max=240 MB
Compressed Class Space: 81%/0% init=0 bytes used=827 KB commit=1 MB max=1,024 MB
Metaspace: 96%/0% init=0 bytes used=6 MB commit=7 MB max=-1 bytes
GC PS Scavenge: spent 0:00:00 doing 0 collections
GC PS MarkSweep: spent 0:00:00 doing 0 collections
Deadlocked Threads: None
Thread Count: 5
"Finalizer" daemon priority=8 id=0x3 group=system cpu=0ms block_cnt=1 wait_cnt=2 WAITING
java.lang.Object.wait(Object.java)
java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144)
java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:165)
java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:216)
"main" priority=5 id=0x1 group=main cpu=405ms block_cnt=0 wait_cnt=0 RUNNABLE
java.lang.Thread.dumpThreads(Thread.java)
java.lang.Thread.getAllStackTraces(Thread.java:1610)
com.widen.util.td.ThreadDumpProducer.getThreads(ThreadDumpProducer.java:24)
com.widen.util.td.JvmThreadDump.doThreads(JvmThreadDump.java:217)
com.widen.util.td.JvmThreadDump.generate(JvmThreadDump.java:58)
com.widen.util.td.TestDump.dumpToStdOut(TestDump.java:14)
sun.reflect.NativeMethodAccessorImpl.invoke0(NativeMethodAccessorImpl.java)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
org.junit.runners.ParentRunner.run(ParentRunner.java:363)
org.junit.runner.JUnitCore.run(JUnitCore.java:137)
com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
"Monitor Ctrl-Break" daemon priority=5 id=0x5 group=main cpu=22ms block_cnt=0 wait_cnt=0 RUNNABLE
java.net.SocketInputStream.socketRead0(SocketInputStream.java)
java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
java.net.SocketInputStream.read(SocketInputStream.java:171)
java.net.SocketInputStream.read(SocketInputStream.java:141)
sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
java.io.InputStreamReader.read(InputStreamReader.java:184)
java.io.BufferedReader.fill(BufferedReader.java:161)
java.io.BufferedReader.readLine(BufferedReader.java:324)
java.io.BufferedReader.readLine(BufferedReader.java:389)
com.intellij.rt.execution.application.AppMainV2$1.run(AppMainV2.java:64)
"Reference Handler" daemon priority=10 id=0x2 group=system cpu=0ms block_cnt=1 wait_cnt=1 WAITING
java.lang.Object.wait(Object.java)
java.lang.Object.wait(Object.java:502)
java.lang.ref.Reference.tryHandlePending(Reference.java:191)
java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)
"Signal Dispatcher" daemon priority=9 id=0x4 group=system cpu=0ms block_cnt=0 wait_cnt=0 RUNNABLE
Apache, Version 2.0