DTrace Probes in HotSpot VM

Overview

With the introduction of DTrace on Solaris 10, DTrace support has been added to the Java SE 6 HotSpot VM. The hotspot and hotspot_jni providers make available probes that can be used to monitor JVM internal state and activities as well as the Java application that is running. All of the probes are USDT probes and are accessed using the process-id of the JVM process. The probe details are listed in the next section, and the API is provided in the reference section.

The hotspot Provider

The hotspot provider makes available probes that can be used to track the lifespan of the VM, thread start and stop events, GC and memory pool statistics, method compilations, and monitor activity. With a startup flag, additional probes are enabled which can be used to monitor the running Java program, such as method enter and return probes, and object allocations. All of the hotspot probes originate in the VM library (libjvm.so), so they are also provided from programs which embed the VM.

Many of the probes in the provider have arguments that can be examined to provide further details on the state of the VM. Many of these probes' arguments are opaque IDs which can be used to link probe firings to each other, however strings and other data are also provided. When string values are provided, they are always present as a pair: a pointer to unterminated modified UTF-8 data (see JVM spec :4.4.7) , and a length value which indicates the extent of that data. Because the string data (even when none of the characters are outside the ASCII range) is not guaranteed to be terminated by a NUL character, it is necessary to use the length-terminated copyinstr() intrinsic to read the string data from the process.

VM Life-cycle Probes

The probes that relate to the VM life-cycle are indicated below. None have any arguments at this time.

vm-init-begin Probe that fires just as the VM initialization begins
vm-init-end Probe that fires when the VM initialization finishes, and the VM is ready to start running application code
vm-shutdown Probe that fires as the VM is shutting down due to program termination or an error

Thread Lifecycle Probes

Two probes are available for tracking thread start and stop events.

thread-start Probe that fires when a thread is started. Provides the arguments listed below
thread-stop Probe that fires when the thread has completed. Provides the arguments listed below

Each of these probes has the following arguments:

args[0] A pointer to UTF-8 string data which contains the thread name
args[1] The length of the thread name data (in bytes)
args[2] The Java thread ID. This is the value that will match other HotSpot VM probes which contain a thread argument
args[3] The native/OS thread ID. This is the ID assigned by the host operating system
args[4] A boolean value which indicates if this thread is a daemon or not. A value of 0 indicates a non-daemon thread

Classloading Probes

Two probes are available for tracking class loading and unloading activity.

class-loaded Probe that fires when a class has been loaded
class-unloaded Probe that fires when a class has been unloaded from the system

Each of these probes has the following arguments:

args[0] A pointer to UTF-8 string data which contains the name of the class that was loaded
args[1] The length of the class name data (in bytes)
args[2] The class loader ID, which is a unique identifier for a class loader in the VM. This is the class loader that loaded the class
args[3] A boolean value which indicates if the class is a shared class (if the class was loaded from the shared archive)

Garbage Collection Probes

Probes are available that can be used to measure the duration of a system-wide garbage collection cycle (for those garbage collectors that have a defined begin and end). Each memory pool can be tracked independently. The probes for individual pools pass the memory manager's name, the pool name, and pool usage information at both the begin and end of pool collection.

The provided GC-related probes are:

gc-begin Probe that fires when a system-wide collection is about to start. It's one argument (arg[0]) is a boolean value which indicates if this is to be a Full GC.
gc-end Probe that fires when a system-wide collection has completed. No arguments.
mem-pool-gc-begin Probe that fires when an individual memory pool is about to be collected. Provides the arguments listed below
mem-pool-gc-end Probe that fires after an individual memory pool has been collected. Provides the arguments listed below

Memory pool probe arguments:

args[0] A pointer to UTF-8 string data which contains the name of the manager which manages this memory pool
args[1] The length of the manager name data (in bytes)
args[2] A pointer to UTF-8 string data which contains the name of the memory pool
args[3] The length of the memory pool name data (in bytes)
args[4] The initial size of the memory pool (in bytes)
args[5] The amount of memory in use in the memory pool (in bytes)
args[6] The number of committed pages in the memory pool
args[7] The maximum size of the memory pool

Method Compilation Probes

Probes are available to indicate which methods are being compiled and by which compiler. Probes are also available to track the installing and uninstalling of compiled methods.

Probes that mark the begin and end of method compilation:

method-compile-begin Probe that fires as method compilation begins. Provides the arguments listed below
method-compile-end Probe that fires when method compilation completes. In addition to the arguments listed below, argv[8] is a boolean value which indicates if the compilation was successful

Method compilation probe arguments:

args[0] A pointer to UTF-8 string data which contains the name of the compiler which is compiling this method
args[1] The length of the compiler name data (in bytes)
args[2] A pointer to UTF-8 string data which contains the name of the class of the method being compiled
args[3] The length of the class name data (in bytes)
args[4] A pointer to UTF-8 string data which contains the name of the method being compiled
args[5] The length of the method name data (in bytes)
args[6] A pointer to UTF-8 string data which contains the signature of the method being compiled
args[7] The length of the signature data (in bytes)

When compiled methods are installed for execution or uninstalled, the following probes are fired:

compiled-method-load Probe that fires when a compiled method is installed. In addition to the arguments listed below, argv[6] contains a pointer to the compiled code, and argv[7] is the size of the compiled code
compiled-method-unload Probe that fires when a compiled method is uninstalled. Provides the arguments listed below

Compiled method loading probe arguments:

args[0] A pointer to UTF-8 string data which contains the name of the class of the method being installed
args[1] The length of the class name data (in bytes)
args[2] A pointer to UTF-8 string data which contains the name of the method being installed
args[3] The length of the method name data (in bytes)
args[4] A pointer to UTF-8 string data which contains the signature of the method being installed
args[5] The length of the signature data (in bytes)

Monitor Probes

As the Java application runs, threads will enter and exit monitors, wait on monitors, and perform notifications. Probes are available for all wait and notification events, as well as for contended monitor entry and exit events. A contended monitor entry is the situation where a thread attempts to enter a monitor when another thread is already in the monitor. A contended monitor exit event occurs when a thread leaves a monitor and other threads are waiting to enter to the monitor. Thus, contended enter and contended exit events may not match up to each other in relation to the thread that encounters these events, though it is expected that a contended exit from one thread should match up to a contended enter on another thread (the thread waiting to enter the monitor).

All monitor events provide the thread ID, a monitor ID, and the type of the class of the object as arguments. It is expected that the thread and the class will help map back to the Java program, while the monitor ID can provide matching information between probe firings.

Since the existence of these probes in the VM causes performance degradation, they will only fire if the VM flag -XX:+ExtendedDTraceProbes is set on the java command line. This flag can be turned on and off dynamically at runtime by using the jinfo utility.

If the above flag is off, the monitor probes are still present in the probe listing obtainable from dtrace, but will remain dormant and will never fire. It is intended that this restriction be removed in future releases of the VM, where these probes will be enabled all the time with no impact to performance.

The available probes:

monitor-contended-enter Probe that fires as a thread attempts to enter a contended monitor
monitor-contended-entered Probe that fires when a thread successfully enters the contended monitor
monitor-contended-exit Probe that fires when a thread leaves a monitor and other threads are waiting to enter
monitor-wait Probe that fires as a thread begins a wait on a monitor via Object.wait(). The probe has an additional argument, args[4] which is a 'long' value which indicates the timeout being used.
monitor-waited Probe that fires when a thread completes an Object.wait().
monitor-notify Probe that fires when a thread calls Object.notify() to notify waiters on a monitor
monitor-notifyAll Probe that fires when a thread calls Object.notifyAll() to notify waiters on a monitor

Monitor probe arguments:

args[0] The Java thread identifier for the thread performing the monitor operation
args[1] A unique, but opaque identifier for the specific monitor that the action is performed upon
args[2] A pointer to UTF-8 string data which contains the class name of the object being acted upon
args[3] The length of the class name data (in bytes)

Application Tracking Probes

A few probes are provided to allow fine-grained examination of Java thread execution. These consist of probes that fire anytime a method is entered or returned from, as well as a probe that fires whenever a Java object has been allocated.

Since the existence of these probes in the VM causes performance degradation, they will only fire if the VM has the ExtendedDTraceProbes flag enabled. By default the probes are all present in any listing of the probes in the VM, but are dormant without the appropriate flag. It is intended that this restriction be removed in future releases of the VM, where these probes will be enabled all the time with no impact to performance.

The method entry and return probes:

method-entry Probe that fires when a method is being entered.
method-return Probe that fires when a method returns, either normally or due to an exception.

Method probe arguments:

args[0] The Java thread ID of the thread that is entering or leaving the method
args[1] A pointer to UTF-8 string data which contains the name of the class of the method
args[2] The length of the class name data (in bytes)
args[3] A pointer to UTF-8 string data which contains the name of the method
args[4] The length of the method name data (in bytes)
args[5] A pointer to UTF-8 string data which contains the signature of the method
args[6] The length of the signature data (in bytes)

The available allocation probe:

object-alloc Probe that fires when any object is allocated, provided that the ExtendedDTraceProbes flag is enabled.

The object allocation probe has the following arguments:

args[0] The Java thread ID of the thread that is allocating the object
args[1] A pointer to UTF-8 string data which contains the class name of the object being allocated
args[2] The length of the class name data (in bytes)
args[3] The size of the object being allocated

The hotspot_jni Provider

In order to call from native code to Java code, due to embedding of the VM in an application or execution of native code within a Java application, the native code must make a call through the JNI interface. The JNI interface provides a number of methods for invoking Java code and examining the state of the VM. DTrace probes are provided at the entry point and return point for each of these methods. The probes are provided by the hotspot_jni provider. The name of the probe is the name of the JNI method, appended with "-entry" for entry probes, and "-return" for return probes. The arguments available at each entry probe are the arguments that were provided to the function (with the exception of the Invoke* methods, which omit the arguments that are passed to the Java method). The return probes have the return value of the method as an argument (if available).

Reference

provider hotspot {
  probe vm-init-begin();
  probe vm-init-end();
  probe vm-shutdown();
  probe class-loaded(
      char* class_name, uintptr_t class_name_len, uintptr_t class_loader_id, bool is_shared);
  probe class-unloaded(
      char* class_name, uintptr_t class_name_len, uintptr_t class_loader_id, bool is_shared);
  probe gc-begin(bool is_full);
  probe gc-end();
  probe mem-pool-gc-begin(
      char* mgr_name, uintptr_t mgr_name_len, char* pool_name, uintptr_t pool_name_len, 
      uintptr_t initial_size, uintptr_t used, uintptr_t committed, uintptr_t max_size);
  probe mem-pool-gc-end(
      char* mgr_name, uintptr_t mgr_name_len, char* pool_name, uintptr_t pool_name_len, 
      uintptr_t initial_size, uintptr_t used, uintptr_t committed, uintptr_t max_size);
  probe thread-start(
      char* thread_name, uintptr_t thread_name_length, 
      uintptr_t java_thread_id, uintptr_t native_thread_id, bool is_daemon);
  probe thread-stop(
      char* thread_name, uintptr_t thread_name_length, 
      uintptr_t java_thread_id, uintptr_t native_thread_id, bool is_daemon);
  probe method-compile-begin(
      char* class_name, uintptr_t class_name_len, 
      char* method_name, uintptr_t method_name_len,
      char* signature, uintptr_t signature_len);
  probe method-compile-end(
      char* class_name, uintptr_t class_name_len, 
      char* method_name, uintptr_t method_name_len,
      char* signature, uintptr_t signature_len,
      bool is_success);
  probe compiled-method-load(
      char* class_name, uintptr_t class_name_len, 
      char* method_name, uintptr_t method_name_len,
      char* signature, uintptr_t signature_len,
      void* code, uintptr_t code_size);
  probe compiled-method-unload(
      char* class_name, uintptr_t class_name_len, 
      char* method_name, uintptr_t method_name_len,
      char* signature, uintptr_t signature_len);
  probe monitor-contended-enter(
      uintptr_t java_thread_id, uintptr_t monitor_id, 
      char* class_name, uintptr_t class_name_len);
  probe monitor-contended-entered(
      uintptr_t java_thread_id, uintptr_t monitor_id, 
      char* class_name, uintptr_t class_name_len);
  probe monitor-contended-exit(
      uintptr_t java_thread_id, uintptr_t monitor_id, 
      char* class_name, uintptr_t class_name_len);
  probe monitor-wait(
      uintptr_t java_thread_id, uintptr_t monitor_id, 
      char* class_name, uintptr_t class_name_len,
      uintptr_t timeout);
  probe monitor-waited(
      uintptr_t java_thread_id, uintptr_t monitor_id, 
      char* class_name, uintptr_t class_name_len);
  probe monitor-notify(
      uintptr_t java_thread_id, uintptr_t monitor_id, 
      char* class_name, uintptr_t class_name_len);
  probe monitor-notifyAll(
      uintptr_t java_thread_id, uintptr_t monitor_id, 
      char* class_name, uintptr_t class_name_len);
  probe method-entry(
      uintptr_t java_thread_id, char* class_name, uintptr_t class_name_len,
      char* method_name, uintptr_t method_name_len,
      char* signature, uintptr_t signature_len);
  probe method-return(
      uintptr_t java_thread_id, char* class_name, uintptr_t class_name_len,
      char* method_name, uintptr_t method_name_len,
      char* signature, uintptr_t signature_len);
  probe object-alloc(
      uintptr_t java_thread_id, char* class_name, uintptr_t class_name_len,
      uintptr_t size);
};

provider hotspot_jni {
  probe AllocObject-entry(void*, void*);
  probe AllocObject-return(void*);
  probe AttachCurrentThreadAsDaemon-entry(void*, void**, void*);
  probe AttachCurrentThreadAsDaemon-return(uint32_t);
  probe AttachCurrentThread-entry(void*, void**, void*);
  probe AttachCurrentThread-return(uint32_t);
  probe CallBooleanMethodA-entry(void*, void*, uintptr_t);
  probe CallBooleanMethodA-return(uintptr_t);
  probe CallBooleanMethod-entry(void*, void*, uintptr_t);
  probe CallBooleanMethod-return(uintptr_t);
  probe CallBooleanMethodV-entry(void*, void*, uintptr_t);
  probe CallBooleanMethodV-return(uintptr_t);
  probe CallByteMethodA-entry(void*, void*, uintptr_t);
  probe CallByteMethodA-return(char);
  probe CallByteMethod-entry(void*, void*, uintptr_t);
  probe CallByteMethod-return(char);
  probe CallByteMethodV-entry(void*, void*, uintptr_t);

  probe CallByteMethodV-return(char);
  probe CallCharMethodA-entry(void*, void*, uintptr_t);
  probe CallCharMethodA-return(uint16_t);
  probe CallCharMethod-entry(void*, void*, uintptr_t);
  probe CallCharMethod-return(uint16_t);
  probe CallCharMethodV-entry(void*, void*, uintptr_t);
  probe CallCharMethodV-return(uint16_t);
  probe CallDoubleMethodA-entry(void*, void*, uintptr_t);
  probe CallDoubleMethodA-return(double);
  probe CallDoubleMethod-entry(void*, void*, uintptr_t);
  probe CallDoubleMethod-return(double);
  probe CallDoubleMethodV-entry(void*, void*, uintptr_t);
  probe CallDoubleMethodV-return(double);
  probe CallFloatMethodA-entry(void*, void*, uintptr_t);
  probe CallFloatMethodA-return(float);
  probe CallFloatMethod-entry(void*, void*, uintptr_t);
  probe CallFloatMethod-return(float);
  probe CallFloatMethodV-entry(void*, void*, uintptr_t);
  probe CallFloatMethodV-return(float);
  probe CallIntMethodA-entry(void*, void*, uintptr_t);
  probe CallIntMethodA-return(uint32_t);
  probe CallIntMethod-entry(void*, void*, uintptr_t);
  probe CallIntMethod-return(uint32_t);
  probe CallIntMethodV-entry(void*, void*, uintptr_t);
  probe CallIntMethodV-return(uint32_t);
  probe CallLongMethodA-entry(void*, void*, uintptr_t);
  probe CallLongMethodA-return(uintptr_t);
  probe CallLongMethod-entry(void*, void*, uintptr_t);
  probe CallLongMethod-return(uintptr_t);
  probe CallLongMethodV-entry(void*, void*, uintptr_t);
  probe CallLongMethodV-return(uintptr_t);
  probe CallNonvirtualBooleanMethodA-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualBooleanMethodA-return(uintptr_t);
  probe CallNonvirtualBooleanMethod-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualBooleanMethod-return(uintptr_t);
  probe CallNonvirtualBooleanMethodV-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualBooleanMethodV-return(uintptr_t);
  probe CallNonvirtualByteMethodA-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualByteMethodA-return(char);
  probe CallNonvirtualByteMethod-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualByteMethod-return(char);
  probe CallNonvirtualByteMethodV-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualByteMethodV-return(char);
  probe CallNonvirtualCharMethodA-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualCharMethodA-return(uint16_t);
  probe CallNonvirtualCharMethod-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualCharMethod-return(uint16_t);
  probe CallNonvirtualCharMethodV-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualCharMethodV-return(uint16_t);
  probe CallNonvirtualDoubleMethodA-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualDoubleMethodA-return(double);
  probe CallNonvirtualDoubleMethod-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualDoubleMethod-return(double);
  probe CallNonvirtualDoubleMethodV-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualDoubleMethodV-return(double);
  probe CallNonvirtualFloatMethodA-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualFloatMethodA-return(float);
  probe CallNonvirtualFloatMethod-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualFloatMethod-return(float);
  probe CallNonvirtualFloatMethodV-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualFloatMethodV-return(float);
  probe CallNonvirtualIntMethodA-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualIntMethodA-return(uint32_t);
  probe CallNonvirtualIntMethod-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualIntMethod-return(uint3t);
  probe CallNonvirtualIntMethodV-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualIntMethodV-return(uint32_t);
  probe CallNonvirtualLongMethodA-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualLongMethodA-return(uintptr_t);
  probe CallNonvirtualLongMethod-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualLongMethod-return(uintptr_t);
  probe CallNonvirtualLongMethodV-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualLongMethodV-return(uintptr_t);
  probe CallNonvirtualObjectMethodA-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualObjectMethodA-return(void*);
  probe CallNonvirtualObjectMethod-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualObjectMethod-return(void*);
  probe CallNonvirtualObjectMethodV-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualObjectMethodV-return(void*);
  probe CallNonvirtualShortMethodA-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualShortMethodA-return(uint16_t);
  probe CallNonvirtualShortMethod-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualShortMethod-return(uint16_t);
  probe CallNonvirtualShortMethodV-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualShortMethodV-return(uint16_t);
  probe CallNonvirtualVoidMethodA-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualVoidMethodA-return();
  probe CallNonvirtualVoidMethod-entry(void*, void*, void*, uintptr_t);
  probe CallNonvirtualVoidMethod-return();
  probe CallNonvirtualVoidMethodV-entry(void*, void*, void*, uintptr_t);  
  probe CallNonvirtualVoidMethodV-return();
  probe CallObjectMethodA-entry(void*, void*, uintptr_t);
  probe CallObjectMethodA-return(void*);
  probe CallObjectMethod-entry(void*, void*, uintptr_t);
  probe CallObjectMethod-return(void*);
  probe CallObjectMethodV-entry(void*, void*, uintptr_t);
  probe CallObjectMethodV-return(void*);
  probe CallShortMethodA-entry(void*, void*, uintptr_t);
  probe CallShortMethodA-return(uint16_t);
  probe CallShortMethod-entry(void*, void*, uintptr_t);
  probe CallShortMethod-return(uint16_t);
  probe CallShortMethodV-entry(void*, void*, uintptr_t);
  probe CallShortMethodV-return(uint16_t);
  probe CallStaticBooleanMethodA-entry(void*, void*, uintptr_t);
  probe CallStaticBooleanMethodA-return(uintptr_t);
  probe CallStaticBooleanMethod-entry(void*, void*, uintptr_t);
  probe CallStaticBooleanMethod-return(uintptr_t);
  probe CallStaticBooleanMethodV-entry(void*, void*, uintptr_t);
  probe CallStaticBooleanMethodV-return(uintptr_t);
  probe CallStaticByteMethodA-entry(void*, void*, uintptr_t);
  probe CallStaticByteMethodA-return(char);
  probe CallStaticByteMethod-entry(void*, void*, uintptr_t);
  probe CallStaticByteMethod-return(char);
  probe CallStaticByteMethodV-entry(void*, void*, uintptr_t);
  probe CallStaticByteMethodV-return(char);
  probe CallStaticCharMethodA-entry(void*, void*, uintptr_t);
  probe CallStaticCharMethodA-return(uint16_t);
  probe CallStaticCharMethod-entry(void*, void*, uintptr_t);
  probe CallStaticCharMethod-return(uint16_t);
  probe CallStaticCharMethodV-entry(void*, void*, uintptr_t);
  probe CallStaticCharMethodV-return(uint16_t);
  probe CallStaticDoubleMethodA-entry(void*, void*, uintptr_t);
  probe CallStaticDoubleMethodA-return(double);
  probe CallStaticDoubleMethod-entry(void*, void*, uintptr_t);
  probe CallStaticDoubleMethod-return(double);
  probe CallStaticDoubleMethodV-entry(void*, void*, uintptr_t);
  probe CallStaticDoubleMethodV-return(double);
  probe CallStaticFloatMethodA-entry(void*, void*, uintptr_t);
  probe CallStaticFloatMethodA-return(float);
  probe CallStaticFloatMethod-entry(void*, void*, uintptr_t);
  probe CallStaticFloatMethod-return(float);
  probe CallStaticFloatMethodV-entry(void*, void*, uintptr_t);
  probe CallStaticFloatMethodV-return(float);
  probe CallStaticIntMethodA-entry(void*, void*, uintptr_t);
  probe CallStaticIntMethodA-return(uint32_t);
  probe CallStaticIntMethod-entry(void*, void*, uintptr_t);
  probe CallStaticIntMethod-return(uint32_t);
  probe CallStaticIntMethodentry(void*, void*, uintptr_t);
  probe CallStaticIntMethodV-return(uint32_t);
  probe CallStaticLongMethodA-entry(void*, void*, uintptr_t);
  probe CallStaticLongMethodA-return(uintptr_t);
  probe CallStaticLongMethod-entry(void*, void*, uintptr_t);
  probe CallStaticLongMethod-return(uintptr_t);
  probe CallStaticLongMethodV-entry(void*, void*, uintptr_t);
  probe CallStaticLongMethodV-return(uintptr_t);
  probe CallStaticObjectMethodA-entry(void*, void*, uintptr_t);
  probe CallStaticObjectMethodA-return(void*);
  probe CallStaticObjectMethod-entry(void*, void*, uintptr_t);
  probe CallStaticObjectMethod-return(void*);
  probe CallStaticObjectMethodV-entry(void*, void*, uintptr_t);
  probe CallStaticObjectMethodV-return(void*);
  probe CallStaticShortMethodA-entry(void*, void*, uintptr_t);
  probe CallStaticShortMethodA-return(uint16_t);
  probe CallStaticShortMethod-entry(void*, void*, uintptr_t);
  probe CallStaticShortMethod-return(uint16_t);
  probe CallStaticShortMethodV-entry(void*, void*, uintptr_t);
  probe CallStaticShortMethodV-return(uint16_t);
  probe CallStaticVoidMethodA-entry(void*, void*, uintptr_t);
  probe CallStaticVoidMethodA-return();
  probe CallStaticVoidMethod-entry(void*, void*, uintptr_t);
  probe CallStaticVoidMethod-return(); 
  probe CallStaticVoidMethodV-entry(void*, void*, uintptr_t);  
  probe CallStaticVoidMethodV-return();
  probe CallVoidMethodA-entry(void*, void*, uintptr_t);  
  probe CallVoidMethodA-return();
  probe CallVoidMethod-entry(void*, void*, uintptr_t);  
  probe CallVoidMethod-return(); 
  probe CallVoidMethodV-entry(void*, void*, uintptr_t);  
  probe CallVoidMethodV-return();
  probe CreateJavaVM-entry(void**, void**, void*);
  probe CreateJavaVM-return(uint32_t);
  probe DefineClass-entry(void*, const char*, void*, char, uintptr_t);
  probe DefineClass-return(void*);
  probe DeleteGlobalRef-entry(void*, void*);
  probe DeleteGlobalRef-return();
  probe DeleteLocalRef-entry(void*, void*);
  probe DeleteLocalRef-return();
  probe DeleteWeakGlobalRef-entry(void*, void*);
  probe DeleteWeakGlobalRef-return();
  probe DestroyJavaVM-entry(void*);
  probe DestroyJavaVM-return(uint32_t);
  probe DetachCurrentThread-entry(void*);
  probe DetachCurrentThread-return(uint32_t);
  probe EnsureLocalCapacity-entry(void*, uint32_t);
  probe EnsureLocalCapacity-return(uint32_t);
  probe ExceptionCheck-entry(void*);
  probe ExceptionCheck-return(uintptr_t);
  probe ExceptionClear-entry(void*);
  probe ExceptionClear-return();
  probe ExceptionDescribe-entry(void*);  
  probe ExceptionDescribe-return();
  probe ExceptionOccurred-entry(void*);
  probe ExceptionOccurred-return(void*);
  probe FatalError-entry(void* env, const char*);
  probe FatalError-return();
  probe FindClass-entry(void*, const char*);
  probe FindClass-return(void*);
  probe FromReflectedField-entry(void*, void*);
  probe FromReflectedField-return(uintptr_t);
  probe FromReflectedMethod-entry(void*, void*);
  probe FromReflectedMethod-return(uintptr_t);
  probe GetArrayLength-entry(void*, void*);
  probe GetArrayLength-return(uintptr_t);
  probe GetBooleanArrayElements-entry(void*, void*, uintptr_t*);
  probe GetBooleanArrayElements-return(uintptr_t*);
  probe GetBooleanArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, uintptr_t*);
  probe GetBooleanArrayRegion-return();
  probe GetBooleanField-entry(void*, void*, uintptr_t);
  probe GetBooleanField-return(uintptr_t);
  probe GetByteArrayElements-entry(void*, void*, uintptr_t*);
  probe GetByteArrayElements-return(char*);
  probe GetByteArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, char*);
  probe GetByteArrayRegion-return();
  probe GetByteField-entry(void*, void*, uintptr_t);
  probe GetByteField-return(char);
  probe GetCharArrayElements-entry(void*, void*, uintptr_t*);
  probe GetCharArrayElements-return(uint16_t*);
  probe GetCharArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, uint16_t*);
  probe GetCharArrayRegion-return();
  probe GetCharField-entry(void*, void*, uintptr_t);
  probe GetCharField-return(uint16_t);
  probe GetCreatedJavaVMs-eintptr_t*);
  probe GetCreatedJavaVMs-return(uintptr_t);
  probe GetCreateJavaVMs-entry(void*, uintptr_t, uintptr_t*);
  probe GetCreateJavaVMs-return(uint32_t);
  probe GetDefaultJavaVMInitArgs-entry(void*);
  probe GetDefaultJavaVMInitArgs-return(uint32_t);
  probe GetDirectBufferAddress-entry(void*, void*);
  probe GetDirectBufferAddress-return(void*);
  probe GetDirectBufferCapacity-entry(void*, void*);
  probe GetDirectBufferCapacity-return(uintptr_t);
  probe GetDoubleArrayElements-entry(void*, void*, uintptr_t*);
  probe GetDoubleArrayElements-return(double*);
  probe GetDoubleArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, double*);
  probe GetDoubleArrayRegion-return();
  probe GetDoubleField-entry(void*, void*, uintptr_t);
  probe GetDoubleField-return(double);
  probe GetEnv-entry(void*, void*, void*);
  probe GetEnv-return(uint32_t);
  probe GetFieldID-entry(void*, void*, const char*, const char*);
  probe GetFieldID-return(uintptr_t);
  probe GetFloatArrayElements-entry(void*, void*, uintptr_t*);
  probe GetFloatArrayElements-return(float*);
  probe GetFloatArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, float*);
  probe GetFloatArrayRegion-return();
  probe GetFloatField-entry(void*, void*, uintptr_t);
  probe GetFloatField-return(float);
  probe GetIntArrayElements-entry(void*, void*, uintptr_t*);
  probe GetIntArrayElements-return(uint32_t*);
  probe GetIntArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, uint32_t*);
  probe GetIntArrayRegion-return();
  probe GetIntField-entry(void*, void*, uintptr_t);
  probe GetIntField-return(uint32_t);
  probe GetJavaVM-entry(void*, void**);
  probe GetJavaVM-return(uint32_t);
  probe GetLongArrayElements-entry(void*, void*, uintptr_t*);
  probe GetLongArrayElements-return(uintptr_t*);
  probe GetLongArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, uintptr_t*);
  probe GetLongArrayRegion-return();
  probe GetLongField-entry(void*, void*, uintptr_t);
  probe GetLongField-return(uintptr_t);
  probe GetMethodID-entry(void*, void*, const char*, const char*);
  probe GetMethodID-return(uintptr_t);
  probe GetObjectArrayElement-entry(void*, void*, uintptr_t);
  probe GetObjectArrayElement-return(void*);
  probe GetObjectClass-entry(void*, void*);
  probe GetObjectClass-return(void*);
  probe GetObjectField-entry(void*, void*, uintptr_t);
  probe GetObjectField-return(void*);
  probe GetObjectRefType-entry(void*, void*);
  probe GetObjectRefType-return(void*);
  probe GetPrimitiveArrayCritical-entry(void*, void*, uintptr_t*);
  probe GetPrimitiveArrayCritical-return(void*);
  probe GetShortArrayElements-entry(void*, void*, uintptr_t*);
  probe GetShortArrayElements-return(uint16_t*);
  probe GetShortArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, uint16_t*);
  probe GetShortArrayRegion-return();
  probe GetShortField-entry(void*, void*, uintptr_t);
  probe GetShortField-return(uint16_t);
  probe GetStaticBooleanField-entry(void*, void*, uintptr_t);
  probe GetStaticBooleanField-return(uintptr_t);
  probe GetStaticByteField-entry(void*, void*, uintptr_t);
  probe GetStaticByteField-return(char);
  probe GetStaticCharField-entry(void*, void*, uintptr_t);
  probe GetStaticCharField-return(uint16_t);
  probe GetStaticDoubleField-entry(void*, void*, uintptr_t);
  probe GetStaticDoubleField-return(double);
  probe GetStaticFieldID-entry(void*, void*, const char*, const char*);
  probe GetStaticFieldID-return(uintptr_t);
  probe GetStaticFloatField-entry(void*, void*, uintptr_t);
  probe GetStaticFloatField-return(float);
  probe GetStaticIntField-entry(void*, void*, uintptr_t);
  probe GetStaticIntField-return(uint32_t);
  probe GetStaticLongField-entry(void*, void*, uintptr_t);
  probe GetStaticLongField-return(uintptr_t);
  probe GetStaticMethodID-entry(void*, void*, const char*, const char*);
  probe GetStaticMethodID-return(uintptr_t);
  probe GetStaticObjectField-entry(void*, void*, uintptr_t);
  probe GetStaticObjectField-return(void*);
  probe GetStaticShortField-entry(void*, void*, uintptr_t);
  probe GetStaticShortField-return(uint16_t);
  pro GetStringChars-entry(void*, void*, uintptr_t*);
  probe GetStringChars-return(const uint16_t*);
  probe GetStringCritical-entry(void*, void*, uintptr_t*);
  probe GetStringCritical-return(const uint16_t*);
  probe GetStringLength-entry(void*, void*);
  probe GetStringLength-return(uintptr_t);
  probe GetStringRegion-entry(void*, void*, uintptr_t, uintptr_t, uint16_t*);
  probe GetStringRegion-return();
  probe GetStringUTFChars-entry(void*, void*, uintptr_t*);
  probe GetStringUTFChars-return(const char*);
  probe GetStringUTFLength-entry(void*, void*);
  probe GetStringUTFLength-return(uintptr_t);
  probe GetStringUTFRegion-entry(void*, void*, uintptr_t, uintptr_t, char*);
  probe GetStringUTFRegion-return();
  probe GetSuperclass-entry(void*, void*);
  probe GetSuperclass-return(void*);
  probe GetVersion-entry(void*);
  probe GetVersion-return(uint32_t);
  probe IsAssignableFrom-entry(void*, void*, void*);
  probe IsAssignableFrom-return(uintptr_t);
  probe IsInstanceOf-entry(void*, void*, void*);
  probe IsInstanceOf-return(uintptr_t);
  probe IsSameObject-entry(void*, void*, void*);
  probe IsSameObject-return(uintptr_t);
  probe MonitorEnter-entry(void*, void*);
  probe MonitorEnter-return(uint32_t);
  probe MonitorExit-entry(void*, void*);
  probe MonitorExit-return(uint32_t);
  probe NewBooleanArray-entry(void*, uintptr_t);
  probe NewBooleanArray-return(void*);
  probe NewByteArray-entry(void*, uintptr_t);
  probe NewByteArray-return(void*);
  probe NewCharArray-entry(void*, uintptr_t);
  probe NewCharArray-return(void*);
  probe NewDirectByteBuffer-entry(void*, void*, uintptr_t);
  probe NewDirectByteBuffer-return(void*);
  probe NewDoubleArray-entry(void*, uintptr_t);
  probe NewDoubleArray-return(void*);
  probe NewFloatArray-entry(void*, uintptr_t);
  probe NewFloatArray-return(void*);
  probe NewGlobalRef-entry(void*, void*);
  probe NewGlobalRef-return(void*);
  probe NewIntArray-entry(void*, uintptr_t);
  probe NewIntArray-return(void*);
  probe NewLocalRef-entry(void*, void*);
  probe NewLocalRef-return(void*);
  probe NewLongArray-entry(void*, uintptr_t);
  probe NewLongArray-return(void*);
  probe NewObjectA-entry(void*, void*, uintptr_t);  
  probe NewObjectA-return(void*);
  probe NewObjectArray-entry(void*, uintptr_t, void*, void*);
  probe NewObjectArray-return(void*);
  probe NewObject-entry(void*, void*, uintptr_t); 
  probe NewObject-return(void*);
  probe NewObjectV-entry(void*, void*, uintptr_t);  
  probe NewObjectV-return(void*);
  probe NewShortArray-entry(void*, uintptr_t);
  probe NewShortArray-return(void*);
  probe NewString-entry(void*, const uint16_t*, uintptr_t);
  probe NewString-return(void*);
  probe NewStringUTF-entry(void*, const char*);
  probe NewStringUTF-return(void*);
  probe NewWeakGlobalRef-entry(void*, void*);
  probe NewWeakGlobalRef-return(void*);
  probe PopLocalFrame-entry(void*, void*);
  probe PopLocalFrame-return(void*);
  probe PushLocalFrame-entry(void*, uint32_t);
  probe PushLocalFrame-return(uint32_t);
  probe RegisterNatives-entry(void*, void*, const void*, uint32_t);  
  probe RegisterNatives-return(uint32_t);
  probe ReleaseBooleanArrayElements-entry(void*, void*, uintptr_t*, uint32_t);
  probe ReleaseBooleanArrayElements-return();
  probe ReleaseByteArrayElements-entry(void*, void*, char*, uint32_t);
  probe ReleaseByteArrayElements-return();
  probe ReleaseCharArrayElements-entry(void*, void*, uint16_t*, uint32_t);
  probe ReleaseCharArrayElements-return();
  probe ReleaseDoubleArrayElements-entry(void*, void*, double*, uint32_t);
  probe ReleaseDoubleArrayElements-return();
  probe ReleaseFloatArrayElements-entry(void*, void*, float*, uint32_t);
  probe ReleaseFloatArrayElements-return();
  probe ReleaseIntArrayElements-entry(void*, void*, uint32_t*, uint32_t);
  probe ReleaseIntArrayElements-return();
  probe ReleaseLongArrayElements-entry(void*, void*, uintptr_t*, uint32_t);
  probe ReleaseLongArrayElements-return();
  probe ReleaseObjectArrayElements-entry(void*, void*, void**, uint32_t);
  probe ReleaseObjectArrayElements-return();
  probe Releasey(void*, void*, void*, uint32_t);
  probe ReleasePrimitiveArrayCritical-return();
  probe ReleaseShortArrayElements-entry(void*, void*, uint16_t*, uint32_t);
  probe ReleaseShortArrayElements-return();
  probe ReleaseStringChars-entry(void*, void*, const uint16_t*);
  probe ReleaseStringChars-return();
  probe ReleaseStringCritical-entry(void*, void*, const uint16_t*);
  probe ReleaseStringCritical-return();
  probe ReleaseStringUTFChars-entry(void*, void*, const char*);
  probe ReleaseStringUTFChars-return();
  probe SetBooleanArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, const uintptr_t*);
  probe SetBooleanArrayRegion-return();
  probe SetBooleanField-entry(void*, void*, uintptr_t, uintptr_t);
  probe SetBooleanField-return();
  probe SetByteArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, const char*);
  probe SetByteArrayRegion-return();
  probe SetByteField-entry(void*, void*, uintptr_t, char);
  probe SetByteField-return();
  probe SetCharArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, const uint16_t*);
  probe SetCharArrayRegion-return();
  probe SetCharField-entry(void*, void*, uintptr_t, uint16_t);
  probe SetCharField-return();
  probe SetDoubleArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, const double*);
  probe SetDoubleArrayRegion-return();
  probe SetDoubleField-entry(void*, void*, uintptr_t, double);
  probe SetDoubleField-return();
  probe SetFloatArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, const float*);
  probe SetFloatArrayRegion-return();
  probe SetFloatField-entry(void*, void*, uintptr_t, float);
  probe SetFloatField-return();
  probe SetIntArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, const uint32_t*);
  probe SetIntArrayRegion-return();
  probe SetIntField-entry(void*, void*, uintptr_t, uint32_t);
  probe SetIntField-return();
  probe SetLongArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, const uintptr_t*);
  probe SetLongArrayRegion-return();
  probe SetLongField-entry(void*, void*, uintptr_t, uintptr_t);
  probe SetLongField-return();
  probe SetObjectArrayElement-entry(void*, void*, uintptr_t, void*);
  probe SetObjectArrayElement-return();
  probe SetObjectField-entry(void*, void*, uintptr_t, void*);
  probe SetObjectField-return();
  probe SetShortArrayRegion-entry(void*, void*, uintptr_t, uintptr_t, const uint16_t*);
  probe SetShortArrayRegion-return();
  probe SetShortField-entry(void*, void*, uintptr_t, uint16_t);
  probe SetShortField-return();
  probe SetStaticBooleanField-entry(void*, void*, uintptr_t, uintptr_t);
  probe SetStaticBooleanField-return();
  probe SetStaticByteField-entry(void*, void*, uintptr_t, char);
  probe SetStaticByteField-return();
  probe SetStaticCharField-entry(void*, void*, uintptr_t, uint16_t);
  probe SetStaticCharField-return();
  probe SetStaticDoubleField-entry(void*, void*, uintptr_t, double);
  probe SetStaticDoubleField-return();
  probe SetStaticFloatField-entry(void*, void*, uintptr_t, float);
  probe SetStaticFloatField-return();
  probe SetStaticIntField-entry(void*, void*, uintptr_t, uint32_t);
  probe SetStaticIntField-return();
  probe SetStaticLongField-entry(void*, void*, uintptr_t, uintptr_t);
  probe SetStaticLongField-return();
  probe SetStaticObjectField-entry(void*, void*, uintptr_t, void*);
  probe SetStaticObjectField-return();
  probe SetStaticShortField-entry(void*, void*, uintptr_t, uint16_t);
  probe SetStaticShortField-return();
  probe Throw-entry(void*, void*);
  probe ThrowNew-entry(void*, void*, const char*);  
  probe ThrowNew-return(uint32_t);
  probe Throw-return(uint32_t);
  probe ToReflectedField-entry(void*, void*, uintptr_t, uintptr_t);
  probe ToReflectedField-return(void*);
  probe ToReflectedMethod-entry(void*, void*, uintptr_t, uintptr_t);
  probe ToReflectedMethod-return(void*);
  probe UnregisterNatives-entry(void*, void*);  
  probe UnregisterNatives-return(uint32_t);
};