java.lang.Object | |
↳ | java.lang.Runtime |
Allows Java applications to interface with the environment in which they are
running. Applications can not create an instance of this class, but they can
get a singleton instance by invoking getRuntime()
.
Public Methods | |||||||||||
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Registers a VM shutdown hook.
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Returns the number of processor cores available to the VM, at least 1.
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Executes the specified command and its arguments in a separate native
process.
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Executes the specified program in a separate native process.
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Executes the specified command and its arguments in a separate native
process.
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Executes the specified program in a separate native process.
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Executes the specified program in a separate native process.
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Executes the specified command and its arguments in a separate native
process.
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Causes the VM to stop running and the program to exit.
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Returns the number of bytes currently available on the heap without expanding the heap.
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Indicates to the VM that it would be a good time to run the
garbage collector.
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This method was deprecated
in API level 1.
Use
InputStreamReader instead.
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This method was deprecated
in API level 1.
Use
OutputStreamWriter instead.
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Returns the single
Runtime instance for the current application. | |||||||||||
Causes the VM to stop running, and the program to exit with the given return code.
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Loads and links the dynamic library that is identified through the
specified path.
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Loads and links the library with the specified name.
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Returns the maximum number of bytes the heap can expand to.
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Unregisters a previously registered VM shutdown hook.
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Provides a hint to the VM that it would be useful to attempt
to perform any outstanding object finalization.
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This method was deprecated
in API level 1.
This method is unsafe.
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Returns the number of bytes taken by the heap at its current size.
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Switches the output of debug information for instructions on or off.
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Switches the output of debug information for methods on or off.
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[Expand]
Inherited Methods | |||||||||||
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From class
java.lang.Object
|
Registers a VM shutdown hook. A shutdown hook is a
Thread
that is ready to run, but has not yet been started. All
registered shutdown hooks will be executed when the VM
terminates normally (typically when the exit(int)
method is called).
Note that on Android, the application lifecycle does not include VM termination,
so calling this method will not ensure that your code is run. Instead, you should
use the most appropriate lifecycle notification (Activity.onPause
, say).
Shutdown hooks are run concurrently and in an unspecified order. Hooks
failing due to an unhandled exception are not a problem, but the stack
trace might be printed to the console. Once initiated, the whole shutdown
process can only be terminated by calling halt()
.
If runFinalizersOnExit(boolean)
has been called with a true
argument, garbage collection and finalization will take place after
all hooks are either finished or have failed. Then the VM
terminates.
It is recommended that shutdown hooks do not do any time-consuming activities, in order to not hold up the shutdown process longer than necessary.
hook | the shutdown hook to register. |
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IllegalArgumentException | if the hook has already been started or if it has already been registered. |
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IllegalStateException | if the VM is already shutting down. |
Returns the number of processor cores available to the VM, at least 1. Traditionally this returned the number currently online, but many mobile devices are able to take unused cores offline to save power, so releases newer than Android 4.2 (Jelly Bean) return the maximum number of cores that could be made available if there were no power or heat constraints.
Executes the specified command and its arguments in a separate native
process. The new process uses the environment provided in envp
.
Calling this method is equivalent to calling
exec(progArray, envp, null)
.
progArray | the array containing the program to execute as well as any arguments to the program. |
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envp | the array containing the environment to start the new process in. |
Process
object that represents the native
process.IOException | if the requested program can not be executed. |
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Executes the specified program in a separate native process. The new
process uses the environment provided in envp
and the working
directory specified by directory
.
prog | the name of the program to execute. |
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envp | the array containing the environment to start the new process in. |
directory | the directory in which to execute the program. If null ,
execute if in the same directory as the parent process. |
Process
object that represents the native
process.IOException | if the requested program can not be executed. |
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Executes the specified command and its arguments in a separate native
process. The new process uses the environment provided in envp
and the working directory specified by directory
.
progArray | the array containing the program to execute as well as any arguments to the program. |
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envp | the array containing the environment to start the new process in. |
directory | the directory in which to execute the program. If null ,
execute if in the same directory as the parent process. |
Process
object that represents the native
process.IOException | if the requested program can not be executed. |
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Executes the specified program in a separate native process. The new
process uses the environment provided in envp
. Calling this
method is equivalent to calling exec(prog, envp, null)
.
prog | the name of the program to execute. |
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envp | the array containing the environment to start the new process in. |
Process
object that represents the native
process.IOException | if the requested program can not be executed. |
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Executes the specified program in a separate native process. The new
process inherits the environment of the caller. Calling this method is
equivalent to calling exec(prog, null, null)
.
prog | the name of the program to execute. |
---|
Process
object that represents the native
process.IOException | if the requested program can not be executed. |
---|
Executes the specified command and its arguments in a separate native
process. The new process inherits the environment of the caller. Calling
this method is equivalent to calling exec(progArray, null, null)
.
progArray | the array containing the program to execute as well as any arguments to the program. |
---|
Process
object that represents the native
process.IOException | if the requested program can not be executed. |
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Causes the VM to stop running and the program to exit.
If runFinalizersOnExit(boolean)
has been previously invoked with a
true
argument, then all objects will be properly
garbage-collected and finalized first.
Use 0 to signal success to the calling process and 1 to signal failure.
This method is unlikely to be useful to an Android application.
Returns the number of bytes currently available on the heap without expanding the heap. See
totalMemory()
for the heap's current size. When these bytes are exhausted, the heap
may expand. See maxMemory()
for that limit.
Indicates to the VM that it would be a good time to run the garbage collector. Note that this is a hint only. There is no guarantee that the garbage collector will actually be run.
This method was deprecated
in API level 1.
Use InputStreamReader
instead.
Returns the localized version of the specified input stream. The input stream that is returned automatically converts all characters from the local character set to Unicode after reading them from the underlying stream.
stream | the input stream to localize. |
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This method was deprecated
in API level 1.
Use OutputStreamWriter
instead.
Returns the localized version of the specified output stream. The output stream that is returned automatically converts all characters from Unicode to the local character set before writing them to the underlying stream.
stream | the output stream to localize. |
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Returns the single Runtime
instance for the current application.
Causes the VM to stop running, and the program to exit with the given return code. Use 0 to signal success to the calling process and 1 to signal failure. Neither shutdown hooks nor finalizers are run before exiting. This method is unlikely to be useful to an Android application.
Loads and links the dynamic library that is identified through the
specified path. This method is similar to loadLibrary(String)
,
but it accepts a full path specification whereas loadLibrary
just
accepts the name of the library to load.
pathName | the absolute (platform dependent) path to the library to load. |
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UnsatisfiedLinkError | if the library can not be loaded. |
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Loads and links the library with the specified name. The mapping of the specified library name to the full path for loading the library is implementation-dependent.
libName | the name of the library to load. |
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UnsatisfiedLinkError | if the library can not be loaded. |
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Returns the maximum number of bytes the heap can expand to. See totalMemory()
for the
current number of bytes taken by the heap, and freeMemory()
for the current number of
those bytes actually used by live objects.
Unregisters a previously registered VM shutdown hook.
hook | the shutdown hook to remove. |
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true
if the hook has been removed successfully; false
otherwise.IllegalStateException | if the VM is already shutting down. |
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Provides a hint to the VM that it would be useful to attempt to perform any outstanding object finalization.
This method was deprecated
in API level 1.
This method is unsafe.
Sets the flag that indicates whether all objects are finalized when the VM is about to exit. Note that all finalization which occurs when the system is exiting is performed after all running threads have been terminated.
run | true to enable finalization on exit, false to
disable it. |
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Returns the number of bytes taken by the heap at its current size. The heap may expand or
contract over time, as the number of live objects increases or decreases. See
maxMemory()
for the maximum heap size, and freeMemory()
for an idea of how much
the heap could currently contract.
Switches the output of debug information for instructions on or off. On Android, this method does nothing.
Switches the output of debug information for methods on or off.