java.lang.Object
- dalvik.system.VMRuntime

```
public final class VMRuntime
extends Object
```
Provides an interface to VM-global, Dalvik-specific features. An application cannot create its own Runtime instance, and must obtain one from the getRuntime method.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`long`	`addressOf(Object array)`	Returns the address of array[0].
`String`	`bootClassPath()`	Returns the VM's boot class path.
`void`	`clampGrowthLimit()`	Make the current growth limit the new non growth limit capacity by releasing pages which are after the growth limit but before the non growth limit capacity.
`String`	`classPath()`	Returns the VM's class path.
`void`	`clearGrowthLimit()`	Removes any growth limits, allowing the application to allocate up to the maximum heap size.
`void`	`concurrentGC()`
`void`	`disableJitCompilation()`	Tells the VM to disable the JIT compiler.
`void`	`gcSoftReferences()`	Deprecated.
`static String`	`getCurrentInstructionSet()`	Returns the instruction set of the current runtime.
`long`	`getExternalBytesAllocated()`	Deprecated.
`static String`	`getInstructionSet(String abi)`	Returns the runtime instruction set corresponding to a given ABI.
`long`	`getMinimumHeapSize()`	Deprecated.
`static VMRuntime`	`getRuntime()`	Returns the object that represents the VM instance's Dalvik-specific runtime environment.
`float`	`getTargetHeapUtilization()`	Gets the current ideal heap utilization, represented as a number between zero and one.
`int`	`getTargetSdkVersion()`	Gets the target SDK version.
`boolean`	`is64Bit()`	Returns whether the VM is running in 64-bit mode.
`static boolean`	`is64BitAbi(String abi)`
`static boolean`	`is64BitInstructionSet(String instructionSet)`
`static boolean`	`isBootClassPathOnDisk(String instructionSet)`	Return false if the boot class path for the given instruction set mapped from disk storage, versus being interpretted from dirty pages in memory.
`boolean`	`isCheckJniEnabled()`	Returns whether the VM is running with JNI checking enabled.
`boolean`	`isDebuggerActive()`	Returns true if either a Java debugger or native debugger is active.
`Object`	`newNonMovableArray(Class<?> componentType, int length)`	Returns an array allocated in an area of the Java heap where it will never be moved.
`Object`	`newUnpaddedArray(Class<?> componentType, int minLength)`	Returns an array of at least minLength, but potentially larger.
`void`	`preloadDexCaches()`	Fill in dex caches with classes, fields, and methods that are already loaded.
`String[]`	`properties()`	Returns a copy of the VM's command-line property settings.
`static void`	`registerAppInfo(String appDir, String processName, String pkgname)`	Register application info
`void`	`registerNativeAllocation(int bytes)`	Registers a native allocation so that the heap knows about it and performs GC as required.
`void`	`registerNativeFree(int bytes)`	Registers a native free by reducing the number of native bytes accounted for.
`void`	`requestConcurrentGC()`
`void`	`requestHeapTrim()`
`static void`	`runFinalization(long timeout)`	Wait for objects to be finalized.
`void`	`runFinalizationSync()`	Deprecated.
`void`	`runHeapTasks()`
`long`	`setMinimumHeapSize(long size)`	Deprecated.
`float`	`setTargetHeapUtilization(float newTarget)`	Sets the current ideal heap utilization, represented as a number between zero and one.
`void`	`setTargetSdkVersion(int targetSdkVersion)`	Sets the target SDK version.
`void`	`startHeapTaskProcessor()`
`void`	`startJitCompilation()`	Tells the VM to enable the JIT compiler.
`void`	`stopHeapTaskProcessor()`
`boolean`	`trackExternalAllocation(long size)`	Deprecated.
`void`	`trackExternalFree(long size)`	Deprecated.
`void`	`trimHeap()`
`void`	`updateProcessState(int state)`	Let the heap know of the new process state.
`String`	`vmInstructionSet()`	Returns the VM's instruction set.
`String`	`vmLibrary()`	Returns the name of the shared library providing the VM implementation.
`String`	`vmVersion()`	Returns the VM's version.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - getRuntime
```
public static VMRuntime getRuntime()
```
    Returns the object that represents the VM instance's Dalvik-specific runtime environment.
    
    Returns:
    
    the runtime object
  - properties
```
public String[] properties()
```
    Returns a copy of the VM's command-line property settings. These are in the form "name=value" rather than "-Dname=value".
  - bootClassPath
```
public String bootClassPath()
```
    Returns the VM's boot class path.
  - classPath
```
public String classPath()
```
    Returns the VM's class path.
  - vmVersion
```
public String vmVersion()
```
    Returns the VM's version.
  - vmLibrary
```
public String vmLibrary()
```
    Returns the name of the shared library providing the VM implementation.
  - vmInstructionSet
```
public String vmInstructionSet()
```
    Returns the VM's instruction set.
  - is64Bit
```
public boolean is64Bit()
```
    Returns whether the VM is running in 64-bit mode.
  - isCheckJniEnabled
```
public boolean isCheckJniEnabled()
```
    Returns whether the VM is running with JNI checking enabled.
  - getTargetHeapUtilization
```
public float getTargetHeapUtilization()
```
    Gets the current ideal heap utilization, represented as a number between zero and one. After a GC happens, the Dalvik heap may be resized so that (size of live objects) / (size of heap) is equal to this number.
    
    Returns:
    
    the current ideal heap utilization
  - setTargetHeapUtilization
```
public float setTargetHeapUtilization(float newTarget)
```
    Sets the current ideal heap utilization, represented as a number between zero and one. After a GC happens, the Dalvik heap may be resized so that (size of live objects) / (size of heap) is equal to this number.
    This is only a hint to the garbage collector and may be ignored.
    
    Parameters:
    
    newTarget - the new suggested ideal heap utilization. This value may be adjusted internally.
    
    Returns:
    
    the previous ideal heap utilization
    
    Throws:
    
    IllegalArgumentException - if newTarget is <= 0.0 or >= 1.0
  - setTargetSdkVersion
```
public void setTargetSdkVersion(int targetSdkVersion)
```
    Sets the target SDK version. Should only be called before the app starts to run, because it may change the VM's behavior in dangerous ways. Use 0 to mean "current" (since callers won't necessarily know the actual current SDK version, and the allocated version numbers start at 1), and 10000 to mean CUR_DEVELOPMENT.
  - getTargetSdkVersion
```
public int getTargetSdkVersion()
```
    Gets the target SDK version. See setTargetSdkVersion(int) for special values.
  - getMinimumHeapSize
```
@Deprecated
public long getMinimumHeapSize()
```
    Deprecated.
    
    This method exists for binary compatibility. It was part of a heap sizing API which was removed in Android 3.0 (Honeycomb).
  - setMinimumHeapSize
```
@Deprecated
public long setMinimumHeapSize(long size)
```
    Deprecated.
    
    This method exists for binary compatibility. It was part of a heap sizing API which was removed in Android 3.0 (Honeycomb).
  - gcSoftReferences
```
@Deprecated
public void gcSoftReferences()
```
    Deprecated.
    
    This method exists for binary compatibility. It used to perform a garbage collection that cleared SoftReferences.
  - runFinalizationSync
```
@Deprecated
public void runFinalizationSync()
```
    Deprecated.
    
    This method exists for binary compatibility. It is equivalent to System.runFinalization().
  - trackExternalAllocation
```
@Deprecated
public boolean trackExternalAllocation(long size)
```
    Deprecated.
    
    This method exists for binary compatibility. It was part of the external allocation API which was removed in Android 3.0 (Honeycomb).
  - trackExternalFree
```
@Deprecated
public void trackExternalFree(long size)
```
    Deprecated.
    
    This method exists for binary compatibility. It was part of the external allocation API which was removed in Android 3.0 (Honeycomb).
  - getExternalBytesAllocated
```
@Deprecated
public long getExternalBytesAllocated()
```
    Deprecated.
    
    This method exists for binary compatibility. It was part of the external allocation API which was removed in Android 3.0 (Honeycomb).
  - startJitCompilation
```
public void startJitCompilation()
```
    Tells the VM to enable the JIT compiler. If the VM does not have a JIT implementation, calling this method should have no effect.
  - disableJitCompilation
```
public void disableJitCompilation()
```
    Tells the VM to disable the JIT compiler. If the VM does not have a JIT implementation, calling this method should have no effect.
  - newNonMovableArray
```
public Object newNonMovableArray(Class<?> componentType,
                                 int length)
```
    Returns an array allocated in an area of the Java heap where it will never be moved. This is used to implement native allocations on the Java heap, such as DirectByteBuffers and Bitmaps.
  - newUnpaddedArray
```
public Object newUnpaddedArray(Class<?> componentType,
                               int minLength)
```
    Returns an array of at least minLength, but potentially larger. The increased size comes from avoiding any padding after the array. The amount of padding varies depending on the componentType and the memory allocator implementation.
  - addressOf
```
public long addressOf(Object array)
```
    Returns the address of array[0]. This differs from using JNI in that JNI might lie and give you the address of a copy of the array when in forcecopy mode.
  - clearGrowthLimit
```
public void clearGrowthLimit()
```
    Removes any growth limits, allowing the application to allocate up to the maximum heap size.
  - clampGrowthLimit
```
public void clampGrowthLimit()
```
    Make the current growth limit the new non growth limit capacity by releasing pages which are after the growth limit but before the non growth limit capacity.
  - isDebuggerActive
```
public boolean isDebuggerActive()
```
    Returns true if either a Java debugger or native debugger is active.
  - registerNativeAllocation
```
public void registerNativeAllocation(int bytes)
```
    Registers a native allocation so that the heap knows about it and performs GC as required. If the number of native allocated bytes exceeds the native allocation watermark, the function requests a concurrent GC. If the native bytes allocated exceeds a second higher watermark, it is determined that the application is registering native allocations at an unusually high rate and a GC is performed inside of the function to prevent memory usage from excessively increasing.
  - registerNativeFree
```
public void registerNativeFree(int bytes)
```
    Registers a native free by reducing the number of native bytes accounted for.
  - runFinalization
```
public static void runFinalization(long timeout)
```
    Wait for objects to be finalized. If finalization takes longer than timeout, then the function returns before all objects are finalized.
    
    Parameters:
    
    timeout - timeout in nanoseconds of the maximum time to wait until all pending finalizers are run. If timeout is 0, then there is no timeout. Note that the timeout does not stop the finalization process, it merely stops the wait.
    
    See Also:
    
    Object.wait(long,int)
  - requestConcurrentGC
```
public void requestConcurrentGC()
```
  - concurrentGC
```
public void concurrentGC()
```
  - requestHeapTrim
```
public void requestHeapTrim()
```
  - trimHeap
```
public void trimHeap()
```
  - startHeapTaskProcessor
```
public void startHeapTaskProcessor()
```
  - stopHeapTaskProcessor
```
public void stopHeapTaskProcessor()
```
  - runHeapTasks
```
public void runHeapTasks()
```
  - updateProcessState
```
public void updateProcessState(int state)
```
    Let the heap know of the new process state. This can change allocation and garbage collection behavior regarding trimming and compaction.
  - preloadDexCaches
```
public void preloadDexCaches()
```
    Fill in dex caches with classes, fields, and methods that are already loaded. Typically used after Zygote preloading.
  - registerAppInfo
```
public static void registerAppInfo(String appDir,
                                   String processName,
                                   String pkgname)
```
    Register application info
  - getInstructionSet
```
public static String getInstructionSet(String abi)
```
    Returns the runtime instruction set corresponding to a given ABI. Multiple compatible ABIs might map to the same instruction set. For example armeabi-v7a and armeabi might map to the instruction set arm. This influences the compilation of the applications classes.
  - is64BitInstructionSet
```
public static boolean is64BitInstructionSet(String instructionSet)
```
  - is64BitAbi
```
public static boolean is64BitAbi(String abi)
```
  - isBootClassPathOnDisk
```
public static boolean isBootClassPathOnDisk(String instructionSet)
```
    Return false if the boot class path for the given instruction set mapped from disk storage, versus being interpretted from dirty pages in memory.
  - getCurrentInstructionSet
```
public static String getCurrentInstructionSet()
```
    Returns the instruction set of the current runtime.

Class VMRuntime

Method Summary

Methods inherited from class java.lang.Object

Method Detail

getRuntime

properties

bootClassPath

classPath

vmVersion

vmLibrary

vmInstructionSet

is64Bit

isCheckJniEnabled

getTargetHeapUtilization

setTargetHeapUtilization

setTargetSdkVersion

getTargetSdkVersion

getMinimumHeapSize

setMinimumHeapSize

gcSoftReferences

runFinalizationSync

trackExternalAllocation

trackExternalFree

getExternalBytesAllocated

startJitCompilation

disableJitCompilation

newNonMovableArray

newUnpaddedArray

addressOf

clearGrowthLimit

clampGrowthLimit

isDebuggerActive

registerNativeAllocation

registerNativeFree

runFinalization

requestConcurrentGC

concurrentGC

requestHeapTrim

trimHeap

startHeapTaskProcessor

stopHeapTaskProcessor

runHeapTasks

updateProcessState

preloadDexCaches

registerAppInfo

getInstructionSet

is64BitInstructionSet

is64BitAbi

isBootClassPathOnDisk

getCurrentInstructionSet