Android APIs
public final class

Debug

extends Object
java.lang.Object
   ↳ android.os.Debug

Class Overview

Provides various debugging methods for Android applications, including tracing and allocation counts.

Logging Trace Files

Debug can create log files that give details about an application, such as a call stack and start/stop times for any running methods. See Traceview: A Graphical Log Viewer for information about reading trace files. To start logging trace files, call one of the startMethodTracing() methods. To stop tracing, call stopMethodTracing().

Summary

Nested Classes
class Debug.InstructionCount API for gathering and querying instruction counts. 
class Debug.MemoryInfo This class is used to retrieved various statistics about the memory mappings for this process. 
Constants
int SHOW_CLASSLOADER
int SHOW_FULL_DETAIL Flags for printLoadedClasses().
int SHOW_INITIALIZED
int TRACE_COUNT_ALLOCS Flags for startMethodTracing().
Public Methods
static void changeDebugPort(int port)
This method was deprecated in API level 3. no longer needed or useful
static void dumpHprofData(String fileName)
Dump "hprof" data to the specified file.
static boolean dumpService(String name, FileDescriptor fd, String[] args)
Get a debugging dump of a system service by name.
static void enableEmulatorTraceOutput()
Enable "emulator traces", in which information about the current method is made available to the "emulator -trace" feature.
final static int getBinderDeathObjectCount()
Returns the number of death notification links to Binder objects that exist in the current process.
final static int getBinderLocalObjectCount()
Returns the number of active local Binder objects that exist in the current process.
final static int getBinderProxyObjectCount()
Returns the number of references to remote proxy Binder objects that exist in the current process.
static int getBinderReceivedTransactions()
Returns the number of received transactions from the binder driver.
static int getBinderSentTransactions()
Returns the number of sent transactions from this process.
static int getGlobalAllocCount()
Returns the global count of objects allocated by the runtime between a start and stop.
static int getGlobalAllocSize()
Returns the global size, in bytes, of objects allocated by the runtime between a start and stop.
static int getGlobalClassInitCount()
Returns the number of classes successfully initialized (ie those that executed without throwing an exception) between a start and stop.
static int getGlobalClassInitTime()
Returns the time spent successfully initializing classes between a start and stop.
static int getGlobalExternalAllocCount()
This method was deprecated in API level 11. This method is now obsolete.
static int getGlobalExternalAllocSize()
This method was deprecated in API level 11. This method is now obsolete.
static int getGlobalExternalFreedCount()
This method was deprecated in API level 11. This method is now obsolete.
static int getGlobalExternalFreedSize()
This method was deprecated in API level 11. This method is now obsolete.
static int getGlobalFreedCount()
Returns the global count of objects freed by the runtime between a start and stop.
static int getGlobalFreedSize()
Returns the global size, in bytes, of objects freed by the runtime between a start and stop.
static int getGlobalGcInvocationCount()
Returns the number of non-concurrent GC invocations between a start and stop.
static int getLoadedClassCount()
Get the number of loaded classes.
static void getMemoryInfo(Debug.MemoryInfo memoryInfo)
Retrieves information about this processes memory usages.
static long getNativeHeapAllocatedSize()
Returns the amount of allocated memory in the native heap.
static long getNativeHeapFreeSize()
Returns the amount of free memory in the native heap.
static long getNativeHeapSize()
Returns the size of the native heap.
static long getPss()
Retrieves the PSS memory used by the process as given by the smaps.
static int getThreadAllocCount()
Returns the thread-local count of objects allocated by the runtime between a start and stop.
static int getThreadAllocSize()
Returns the thread-local size of objects allocated by the runtime between a start and stop.
static int getThreadExternalAllocCount()
This method was deprecated in API level 11. This method is now obsolete.
static int getThreadExternalAllocSize()
This method was deprecated in API level 11. This method is now obsolete.
static int getThreadGcInvocationCount()
Returns the number of thread-local non-concurrent GC invocations between a start and stop.
static boolean isDebuggerConnected()
Determine if a debugger is currently attached.
static void printLoadedClasses(int flags)
Dump a list of all currently loaded class to the log file.
static void resetAllCounts()
Clears all the global and thread-local memory allocation counters.
static void resetGlobalAllocCount()
Clears the global count of objects allocated.
static void resetGlobalAllocSize()
Clears the global size of objects allocated.
static void resetGlobalClassInitCount()
Clears the count of classes initialized.
static void resetGlobalClassInitTime()
Clears the count of time spent initializing classes.
static void resetGlobalExternalAllocCount()
This method was deprecated in API level 11. This method is now obsolete.
static void resetGlobalExternalAllocSize()
This method was deprecated in API level 11. This method is now obsolete.
static void resetGlobalExternalFreedCount()
This method was deprecated in API level 11. This method is now obsolete.
static void resetGlobalExternalFreedSize()
This method was deprecated in API level 11. This method is now obsolete.
static void resetGlobalFreedCount()
Clears the global count of objects freed.
static void resetGlobalFreedSize()
Clears the global size of objects freed.
static void resetGlobalGcInvocationCount()
Clears the count of non-concurrent GC invocations.
static void resetThreadAllocCount()
Clears the thread-local count of objects allocated.
static void resetThreadAllocSize()
Clears the thread-local count of objects allocated.
static void resetThreadExternalAllocCount()
This method was deprecated in API level 11. This method is now obsolete.
static void resetThreadExternalAllocSize()
This method was deprecated in API level 11. This method is now obsolete.
static void resetThreadGcInvocationCount()
Clears the thread-local count of non-concurrent GC invocations.
static int setAllocationLimit(int limit)
This method was deprecated in API level 11. This method is now obsolete.
static int setGlobalAllocationLimit(int limit)
This method was deprecated in API level 11. This method is now obsolete.
static void startAllocCounting()
This method was deprecated in API level 18. Accurate counting is a burden on the runtime and may be removed.
static void startMethodTracing(String traceName)
Start method tracing, specifying the trace log file name.
static void startMethodTracing()
Start method tracing with default log name and buffer size.
static void startMethodTracing(String traceName, int bufferSize, int flags)
Start method tracing, specifying the trace log file name and the buffer size.
static void startMethodTracing(String traceName, int bufferSize)
Start method tracing, specifying the trace log file name and the buffer size.
static void startNativeTracing()
Enable qemu tracing.
static void stopAllocCounting()
Stop counting the number and aggregate size of memory allocations.
static void stopMethodTracing()
Stop method tracing.
static void stopNativeTracing()
Stop qemu tracing.
static long threadCpuTimeNanos()
Get an indication of thread CPU usage.
static void waitForDebugger()
Wait until a debugger attaches.
static boolean waitingForDebugger()
Returns "true" if one or more threads is waiting for a debugger to attach.
[Expand]
Inherited Methods
From class java.lang.Object

Constants

public static final int SHOW_CLASSLOADER

Added in API level 1

Constant Value: 2 (0x00000002)

public static final int SHOW_FULL_DETAIL

Added in API level 1

Flags for printLoadedClasses(). Default behavior is to only show the class name.

Constant Value: 1 (0x00000001)

public static final int SHOW_INITIALIZED

Added in API level 1

Constant Value: 4 (0x00000004)

public static final int TRACE_COUNT_ALLOCS

Added in API level 1

Flags for startMethodTracing(). These can be ORed together. TRACE_COUNT_ALLOCS adds the results from startAllocCounting to the trace key file.

Constant Value: 1 (0x00000001)

Public Methods

public static void changeDebugPort (int port)

Added in API level 1

This method was deprecated in API level 3.
no longer needed or useful

Change the JDWP port.

public static void dumpHprofData (String fileName)

Added in API level 3

Dump "hprof" data to the specified file. This may cause a GC.

Parameters
fileName Full pathname of output file (e.g. "/sdcard/dump.hprof").
Throws
UnsupportedOperationException if the VM was built without HPROF support.
IOException if an error occurs while opening or writing files.

public static boolean dumpService (String name, FileDescriptor fd, String[] args)

Added in API level 8

Get a debugging dump of a system service by name.

Most services require the caller to hold android.permission.DUMP.

Parameters
name of the service to dump
fd to write dump output to (usually an output log file)
args to pass to the service's dump method, may be null
Returns
  • true if the service was dumped successfully, false if the service could not be found or had an error while dumping

public static void enableEmulatorTraceOutput ()

Added in API level 1

Enable "emulator traces", in which information about the current method is made available to the "emulator -trace" feature. There is no corresponding "disable" call -- this is intended for use by the framework when tracing should be turned on and left that way, so that traces captured with F9/F10 will include the necessary data. This puts the VM into "profile" mode, which has performance consequences. To temporarily enable tracing, use startNativeTracing().

public static final int getBinderDeathObjectCount ()

Added in API level 1

Returns the number of death notification links to Binder objects that exist in the current process.

public static final int getBinderLocalObjectCount ()

Added in API level 1

Returns the number of active local Binder objects that exist in the current process.

public static final int getBinderProxyObjectCount ()

Added in API level 1

Returns the number of references to remote proxy Binder objects that exist in the current process.

public static int getBinderReceivedTransactions ()

Added in API level 1

Returns the number of received transactions from the binder driver.

Returns
  • The number of received transactions or -1 if it could not read the stats.

public static int getBinderSentTransactions ()

Added in API level 1

Returns the number of sent transactions from this process.

Returns
  • The number of sent transactions or -1 if it could not read t.

public static int getGlobalAllocCount ()

Added in API level 1

Returns the global count of objects allocated by the runtime between a start and stop.

public static int getGlobalAllocSize ()

Added in API level 1

Returns the global size, in bytes, of objects allocated by the runtime between a start and stop.

public static int getGlobalClassInitCount ()

Added in API level 8

Returns the number of classes successfully initialized (ie those that executed without throwing an exception) between a start and stop.

public static int getGlobalClassInitTime ()

Added in API level 8

Returns the time spent successfully initializing classes between a start and stop.

public static int getGlobalExternalAllocCount ()

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

This method exists for compatibility and always returns 0.

public static int getGlobalExternalAllocSize ()

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

This method exists for compatibility and always returns 0.

public static int getGlobalExternalFreedCount ()

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

This method exists for compatibility and always returns 0.

public static int getGlobalExternalFreedSize ()

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

This method exists for compatibility and has no effect.

public static int getGlobalFreedCount ()

Added in API level 1

Returns the global count of objects freed by the runtime between a start and stop.

public static int getGlobalFreedSize ()

Added in API level 1

Returns the global size, in bytes, of objects freed by the runtime between a start and stop.

public static int getGlobalGcInvocationCount ()

Added in API level 1

Returns the number of non-concurrent GC invocations between a start and stop.

public static int getLoadedClassCount ()

Added in API level 1

Get the number of loaded classes.

Returns
  • the number of loaded classes.

public static void getMemoryInfo (Debug.MemoryInfo memoryInfo)

Added in API level 1

Retrieves information about this processes memory usages. This information is broken down by how much is in use by dalivk, the native heap, and everything else.

public static long getNativeHeapAllocatedSize ()

Added in API level 1

Returns the amount of allocated memory in the native heap.

Returns
  • The allocated size in bytes.

public static long getNativeHeapFreeSize ()

Added in API level 1

Returns the amount of free memory in the native heap.

Returns
  • The freed size in bytes.

public static long getNativeHeapSize ()

Added in API level 1

Returns the size of the native heap.

Returns
  • The size of the native heap in bytes.

public static long getPss ()

Added in API level 14

Retrieves the PSS memory used by the process as given by the smaps.

public static int getThreadAllocCount ()

Added in API level 1

Returns the thread-local count of objects allocated by the runtime between a start and stop.

public static int getThreadAllocSize ()

Added in API level 1

Returns the thread-local size of objects allocated by the runtime between a start and stop.

Returns
  • The allocated size in bytes.

public static int getThreadExternalAllocCount ()

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

This method exists for compatibility and has no effect.

public static int getThreadExternalAllocSize ()

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

This method exists for compatibility and has no effect.

public static int getThreadGcInvocationCount ()

Added in API level 1

Returns the number of thread-local non-concurrent GC invocations between a start and stop.

public static boolean isDebuggerConnected ()

Added in API level 1

Determine if a debugger is currently attached.

public static void printLoadedClasses (int flags)

Added in API level 1

Dump a list of all currently loaded class to the log file.

Parameters
flags See constants above.

public static void resetAllCounts ()

Added in API level 1

Clears all the global and thread-local memory allocation counters.

public static void resetGlobalAllocCount ()

Added in API level 1

Clears the global count of objects allocated.

public static void resetGlobalAllocSize ()

Added in API level 1

Clears the global size of objects allocated.

public static void resetGlobalClassInitCount ()

Added in API level 8

Clears the count of classes initialized.

public static void resetGlobalClassInitTime ()

Added in API level 8

Clears the count of time spent initializing classes.

public static void resetGlobalExternalAllocCount ()

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

This method exists for compatibility and has no effect.

public static void resetGlobalExternalAllocSize ()

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

This method exists for compatibility and has no effect.

public static void resetGlobalExternalFreedCount ()

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

This method exists for compatibility and has no effect.

public static void resetGlobalExternalFreedSize ()

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

This method exists for compatibility and has no effect.

public static void resetGlobalFreedCount ()

Added in API level 1

Clears the global count of objects freed.

public static void resetGlobalFreedSize ()

Added in API level 1

Clears the global size of objects freed.

public static void resetGlobalGcInvocationCount ()

Added in API level 1

Clears the count of non-concurrent GC invocations.

public static void resetThreadAllocCount ()

Added in API level 1

Clears the thread-local count of objects allocated.

public static void resetThreadAllocSize ()

Added in API level 1

Clears the thread-local count of objects allocated.

public static void resetThreadExternalAllocCount ()

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

This method exists for compatibility and has no effect.

public static void resetThreadExternalAllocSize ()

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

This method exists for compatibility and has no effect.

public static void resetThreadGcInvocationCount ()

Added in API level 1

Clears the thread-local count of non-concurrent GC invocations.

public static int setAllocationLimit (int limit)

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

Establish an object allocation limit in the current thread. This feature was never enabled in release builds. The allocation limits feature was removed in Honeycomb. This method exists for compatibility and always returns -1 and has no effect.

public static int setGlobalAllocationLimit (int limit)

Added in API level 1

This method was deprecated in API level 11.
This method is now obsolete.

Establish a global object allocation limit. This feature was never enabled in release builds. The allocation limits feature was removed in Honeycomb. This method exists for compatibility and always returns -1 and has no effect.

public static void startAllocCounting ()

Added in API level 1

This method was deprecated in API level 18.
Accurate counting is a burden on the runtime and may be removed.

Start counting the number and aggregate size of memory allocations.

The start method resets the counts and enables counting. The stop method disables the counting so that the analysis code doesn't cause additional allocations. The various get methods return the specified value. And the various reset methods reset the specified count.

Counts are kept for the system as a whole (global) and for each thread. The per-thread counts for threads other than the current thread are not cleared by the "reset" or "start" calls.

public static void startMethodTracing (String traceName)

Added in API level 1

Start method tracing, specifying the trace log file name. The trace file will be put under "/sdcard" unless an absolute path is given. See Traceview: A Graphical Log Viewer for information about reading trace files.

Parameters
traceName Name for the trace log file to create. If traceName is null, this value defaults to "/sdcard/dmtrace.trace". If the files already exist, they will be truncated. If the trace file given does not end in ".trace", it will be appended for you.

public static void startMethodTracing ()

Added in API level 1

Start method tracing with default log name and buffer size. See Traceview: A Graphical Log Viewer for information about reading these files. Call stopMethodTracing() to stop tracing.

public static void startMethodTracing (String traceName, int bufferSize, int flags)

Added in API level 1

Start method tracing, specifying the trace log file name and the buffer size. The trace files will be put under "/sdcard" unless an absolute path is given. See Traceview: A Graphical Log Viewer for information about reading trace files.

When method tracing is enabled, the VM will run more slowly than usual, so the timings from the trace files should only be considered in relative terms (e.g. was run #1 faster than run #2). The times for native methods will not change, so don't try to use this to compare the performance of interpreted and native implementations of the same method. As an alternative, consider using "native" tracing in the emulator via startNativeTracing().

Parameters
traceName Name for the trace log file to create. If traceName is null, this value defaults to "/sdcard/dmtrace.trace". If the files already exist, they will be truncated. If the trace file given does not end in ".trace", it will be appended for you.
bufferSize The maximum amount of trace data we gather. If not given, it defaults to 8MB.
flags Flags to control method tracing. The only one that is currently defined is TRACE_COUNT_ALLOCS.

public static void startMethodTracing (String traceName, int bufferSize)

Added in API level 1

Start method tracing, specifying the trace log file name and the buffer size. The trace files will be put under "/sdcard" unless an absolute path is given. See Traceview: A Graphical Log Viewer for information about reading trace files.

Parameters
traceName Name for the trace log file to create. If traceName is null, this value defaults to "/sdcard/dmtrace.trace". If the files already exist, they will be truncated. If the trace file given does not end in ".trace", it will be appended for you.
bufferSize The maximum amount of trace data we gather. If not given, it defaults to 8MB.

public static void startNativeTracing ()

Added in API level 1

Enable qemu tracing. For this to work requires running everything inside the qemu emulator; otherwise, this method will have no effect. The trace file is specified on the command line when the emulator is started. For example, the following command line
emulator -trace foo
will start running the emulator and create a trace file named "foo". This method simply enables writing the trace records to the trace file.

The main differences between this and startMethodTracing() are that tracing in the qemu emulator traces every cpu instruction of every process, including kernel code, so we have more complete information, including all context switches. We can also get more detailed information such as cache misses. The sequence of calls is determined by post-processing the instruction trace. The qemu tracing is also done without modifying the application or perturbing the timing of calls because no instrumentation is added to the application being traced.

One limitation of using this method compared to using startMethodTracing() on the real device is that the emulator does not model all of the real hardware effects such as memory and bus contention. The emulator also has a simple cache model and cannot capture all the complexities of a real cache.

public static void stopAllocCounting ()

Added in API level 1

Stop counting the number and aggregate size of memory allocations.

public static void stopMethodTracing ()

Added in API level 1

Stop method tracing.

public static void stopNativeTracing ()

Added in API level 1

Stop qemu tracing. See startNativeTracing() to start tracing.

Tracing can be started and stopped as many times as desired. When the qemu emulator itself is stopped then the buffered trace records are flushed and written to the trace file. In fact, it is not necessary to call this method at all; simply killing qemu is sufficient. But starting and stopping a trace is useful for examining a specific region of code.

public static long threadCpuTimeNanos ()

Added in API level 1

Get an indication of thread CPU usage. The value returned indicates the amount of time that the current thread has spent executing code or waiting for certain types of I/O. The time is expressed in nanoseconds, and is only meaningful when compared to the result from an earlier call. Note that nanosecond resolution does not imply nanosecond accuracy. On system which don't support this operation, the call returns -1.

public static void waitForDebugger ()

Added in API level 1

Wait until a debugger attaches. As soon as the debugger attaches, this returns, so you will need to place a breakpoint after the waitForDebugger() call if you want to start tracing immediately.

public static boolean waitingForDebugger ()

Added in API level 1

Returns "true" if one or more threads is waiting for a debugger to attach.