$ jruby -e "%x{ruby -e 'sleep 10'}"
^\2010-05-27 10:40:35
Full thread dump Java HotSpot(TM) Client VM (16.3-b01-279 mixed mode):

"Thread-2" daemon prio=5 tid=0000000029863000 nid=0xb1225000 in Object.wait() [00000000b1224000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	- waiting on <0000000004ae95f8> (a java.lang.Object)
	at org.jruby.util.ShellLauncher$StreamPumper.run(ShellLauncher.java:1149)
	- locked <0000000004ae95f8> (a java.lang.Object)

"Thread-1" daemon prio=5 tid=0000000029862800 nid=0xb1123000 in Object.wait() [00000000b1122000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	- waiting on <0000000004acbb60> (a java.io.PipedInputStream)
	at java.io.PipedInputStream.read(PipedInputStream.java:310)
	- locked <0000000004acbb60> (a java.io.PipedInputStream)
	at java.io.PipedInputStream.read(PipedInputStream.java:361)
	- locked <0000000004acbb60> (a java.io.PipedInputStream)
	at java.io.InputStream.read(InputStream.java:85)
	at org.jruby.util.ShellLauncher$StreamPumper.run(ShellLauncher.java:1157)

"Thread-0" daemon prio=5 tid=0000000029861400 nid=0xb1021000 in Object.wait() [00000000b1020000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	- waiting on <0000000004acb730> (a java.io.PipedInputStream)
	at java.io.PipedInputStream.read(PipedInputStream.java:310)
	- locked <0000000004acb730> (a java.io.PipedInputStream)
	at java.io.PipedInputStream.read(PipedInputStream.java:361)
	- locked <0000000004acb730> (a java.io.PipedInputStream)
	at java.io.InputStream.read(InputStream.java:85)
	at org.jruby.util.ShellLauncher$StreamPumper.run(ShellLauncher.java:1157)

"ScriptThreadProcess: -e" daemon prio=5 tid=000000002982d000 nid=0xb0f1f000 in Object.wait() [00000000b0f1e000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	- waiting on <0000000004b1c548> (a org.jruby.RubyThread)
	at org.jruby.RubyThread.sleep(RubyThread.java:758)
	- locked <0000000004b1c548> (a org.jruby.RubyThread)
	- locked <0000000004b1c548> (a org.jruby.RubyThread)
	at org.jruby.RubyKernel.sleep(RubyKernel.java:806)
	at org.jruby.RubyKernel$s_method_0_1$RUBYINVOKER$sleep.call(org/jruby/RubyKernel$s_method_0_1$RUBYINVOKER$sleep.gen:65535)
	at org.jruby.internal.runtime.methods.JavaMethod$JavaMethodN.call(JavaMethod.java:630)
	at org.jruby.internal.runtime.methods.DynamicMethod.call(DynamicMethod.java:186)
	at org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:309)
	at org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:148)
	at ruby.__dash_e__.__file__(-e:1)
	at ruby.__dash_e__.load(-e)
	at org.jruby.Ruby.runScript(Ruby.java:680)
	at org.jruby.Ruby.runNormally(Ruby.java:563)
	at org.jruby.Ruby.runFromMain(Ruby.java:409)
	at org.jruby.Main.run(Main.java:286)
	at org.jruby.Main.run(Main.java:128)
	at org.jruby.util.ShellLauncher$ScriptThreadProcess.run(ShellLauncher.java:136)
	at java.lang.Thread.run(Thread.java:637)

"Low Memory Detector" daemon prio=5 tid=00000000018bbc00 nid=0xb0d1b000 runnable [0000000000000000]
   java.lang.Thread.State: RUNNABLE

"CompilerThread0" daemon prio=9 tid=00000000018ba400 nid=0xb0c19000 waiting on condition [0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Signal Dispatcher" daemon prio=9 tid=00000000018b9800 nid=0xb0b17000 waiting on condition [0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Surrogate Locker Thread (CMS)" daemon prio=5 tid=00000000018b8800 nid=0xb0a15000 waiting on condition [0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Finalizer" daemon prio=8 tid=00000000018aac00 nid=0xb080f000 in Object.wait() [00000000b080e000]
   java.lang.Thread.State: WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	- waiting on <0000000004810b10> (a java.lang.ref.ReferenceQueue$Lock)
	at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
	- locked <0000000004810b10> (a java.lang.ref.ReferenceQueue$Lock)
	at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)
	at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159)

"Reference Handler" daemon prio=10 tid=00000000018aa000 nid=0xb070d000 in Object.wait() [00000000b070c000]
   java.lang.Thread.State: WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	- waiting on <0000000004810a18> (a java.lang.ref.Reference$Lock)
	at java.lang.Object.wait(Object.java:485)
	at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116)
	- locked <0000000004810a18> (a java.lang.ref.Reference$Lock)

"main" prio=5 tid=0000000001801000 nid=0xb0101000 in Object.wait() [00000000b0100000]
   java.lang.Thread.State: WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	- waiting on <0000000004ae8fb0> (a org.jruby.util.ShellLauncher$StreamPumper)
	at java.lang.Thread.join(Thread.java:1167)
	- locked <0000000004ae8fb0> (a org.jruby.util.ShellLauncher$StreamPumper)
	at java.lang.Thread.join(Thread.java:1220)
	at org.jruby.util.ShellLauncher.handleStreams(ShellLauncher.java:1255)
	at org.jruby.util.ShellLauncher.runAndWait(ShellLauncher.java:391)
	at org.jruby.RubyKernel.backquote(RubyKernel.java:1423)
	at org.jruby.RubyKernel$s_method_1_0$RUBYINVOKER$backquote.call(org/jruby/RubyKernel$s_method_1_0$RUBYINVOKER$backquote.gen:65535)
	at org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:309)
	at org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:148)
	at ruby.__dash_e__.__file__(-e:1)
	at ruby.__dash_e__.load(-e)
	at org.jruby.Ruby.runScript(Ruby.java:680)
	at org.jruby.Ruby.runNormally(Ruby.java:563)
	at org.jruby.Ruby.runFromMain(Ruby.java:409)
	at org.jruby.Main.run(Main.java:286)
	at org.jruby.Main.run(Main.java:128)
	at org.jruby.Main.main(Main.java:97)

"VM Thread" prio=9 tid=00000000018a8400 nid=0xb060b000 runnable

"Gang worker#0 (Parallel GC Threads)" prio=9 tid=0000000001803000 nid=0xb0305000 runnable

"Gang worker#1 (Parallel GC Threads)" prio=9 tid=0000000001804000 nid=0xb0407000 runnable

"Concurrent Mark-Sweep GC Thread" prio=9 tid=0000000001869400 nid=0xb0509000 runnable
"VM Periodic Task Thread" prio=10 tid=00000000018cd800 nid=0xb0e1d000 waiting on condition

"Exception Catcher Thread" prio=10 tid=0000000001802000 nid=0xb0203000 runnable
JNI global references: 813

Heap
 par new generation   total 14784K, used 4531K [0000000004810000, 0000000005810000, 0000000006810000)
  eden space 13184K,  34% used [0000000004810000, 0000000004c7ccd0, 00000000054f0000)
  from space 1600K,   0% used [00000000054f0000, 00000000054f0000, 0000000005680000)
  to   space 1600K,   0% used [0000000005680000, 0000000005680000, 0000000005810000)
 concurrent mark-sweep generation total 49152K, used 0K [0000000006810000, 0000000009810000, 0000000023c10000)
 concurrent-mark-sweep perm gen total 12288K, used 11588K [0000000023c10000, 0000000024810000, 0000000027c10000)