java.lang.Runtime Maven / Gradle / Ivy
/*
This is not an official specification document, and usage is restricted.
NOTICE
(c) 2005-2007 Sun Microsystems, Inc. All Rights Reserved.
Neither this file nor any files generated from it describe a complete
specification, and they may only be used as described below. For
example, no permission is given for you to incorporate this file, in
whole or in part, in an implementation of a Java specification.
Sun Microsystems Inc. owns the copyright in this file and it is provided
to you for informative, as opposed to normative, use. The file and any
files generated from it may be used to generate other informative
documentation, such as a unified set of documents of API signatures for
a platform that includes technologies expressed as Java APIs. The file
may also be used to produce "compilation stubs," which allow
applications to be compiled and validated for such platforms.
Any work generated from this file, such as unified javadocs or compiled
stub files, must be accompanied by this notice in its entirety.
This work corresponds to the API signatures of JSR 219: Foundation
Profile 1.1. In the event of a discrepency between this work and the
JSR 219 specification, which is available at
http://www.jcp.org/en/jsr/detail?id=219, the latter takes precedence.
*/
package java.lang;
import java.io.*;
import java.util.StringTokenizer;
/**
* Every Java application has a single instance of class
* Runtime that allows the application to interface with
* the environment in which the application is running. The current
* runtime can be obtained from the getRuntime method.
*
* An application cannot create its own instance of this class.
*
* @author unascribed
* @version 1.57, 05/03/00
* @see java.lang.Runtime#getRuntime()
* @since JDK1.0
*/
public class Runtime
{
private Runtime() { }
/**
* Returns the runtime object associated with the current Java application.
* Most of the methods of class Runtime are instance
* methods and must be invoked with respect to the current runtime object.
*
* @return the Runtime object associated with the current
* Java application.
*/
public static java.lang.Runtime getRuntime() {
return null;
}
/**
* Terminates the currently running Java virtual machine by initiating its
* shutdown sequence. This method never returns normally. The argument
* serves as a status code; by convention, a nonzero status code indicates
* abnormal termination.
*
*
The virtual machine's shutdown sequence consists of two phases. In
* the first phase all registered {@link #addShutdownHook shutdown hooks},
* if any, are started in some unspecified order and allowed to run
* concurrently until they finish. In the second phase all uninvoked
* finalizers are run if finalization-on-exit
* has been enabled. Once this is done the virtual machine {@link #halt
* halts}.
*
*
If this method is invoked after the virtual machine has begun its
* shutdown sequence then if shutdown hooks are being run this method will
* block indefinitely. If shutdown hooks have already been run and on-exit
* finalization has been enabled then this method halts the virtual machine
* with the given status code if the status is nonzero; otherwise, it
* blocks indefinitely.
*
*
The {@link System#exit(int) System.exit} method is the
* conventional and convenient means of invoking this method.
*
* If process model exists, Runtime.exit() must rely on the process
* exiting to release resources.
*
* If process model does not exist, and a security manager exists,
* the security manager by default must prohibit calls to Runtime.exit()
* by throwing SecurityException. Otherwise, the system will hang
* indefinitely when called.
*
* @param status
* Termination status. By convention, a nonzero status code
* indicates abnormal termination.
*
* @throws SecurityException
* If a security manager is present and its {@link
* SecurityManager#checkExit checkExit} method does not permit
* exiting with the specified status
*
* @see java.lang.SecurityException
* @see java.lang.SecurityManager#checkExit(int)
* @see #addShutdownHook
* @see #removeShutdownHook
* @see #halt(int)
*/
public void exit(int status) { }
/**
* Registers a new virtual-machine shutdown hook.
*
*
The Java virtual machine shuts down in response to two kinds
* of events:
*
*
*
*
- The program exits normally, when the last non-daemon
* thread exits or when the {@link #exit exit} (equivalently,
* {@link System#exit(int) System.exit}) method is invoked, or
*
*
- The virtual machine is terminated in response to a
* user interrupt, such as typing ^C, or a system-wide event,
* such as user logoff or system shutdown.
*
*
*
* A shutdown hook is simply an initialized but unstarted
* thread. When the virtual machine begins its shutdown sequence it will
* start all registered shutdown hooks in some unspecified order and let
* them run concurrently. When all the hooks have finished it will then
* run all uninvoked finalizers if finalization-on-exit has been enabled.
* Finally, the virtual machine will halt. Note that daemon threads will
* continue to run during the shutdown sequence, as will non-daemon threads
* if shutdown was initiated by invoking the {@link #exit exit}
* method.
*
*
Once the shutdown sequence has begun it can be stopped only by
* invoking the {@link #halt halt} method, which forcibly
* terminates the virtual machine.
*
*
Once the shutdown sequence has begun it is impossible to register a
* new shutdown hook or de-register a previously-registered hook.
* Attempting either of these operations will cause an
* {@link IllegalStateException} to be thrown.
*
*
Shutdown hooks run at a delicate time in the life cycle of a virtual
* machine and should therefore be coded defensively. They should, in
* particular, be written to be thread-safe and to avoid deadlocks insofar
* as possible. They should also not rely blindly upon services that may
* have registered their own shutdown hooks and therefore may themselves in
* the process of shutting down.
*
*
Shutdown hooks should also finish their work quickly. When a
* program invokes {@link #exit exit} the expectation is
* that the virtual machine will promptly shut down and exit. When the
* virtual machine is terminated due to user logoff or system shutdown the
* underlying operating system may only allow a fixed amount of time in
* which to shut down and exit. It is therefore inadvisable to attempt any
* user interaction or to perform a long-running computation in a shutdown
* hook.
*
*
Uncaught exceptions are handled in shutdown hooks just as in any
* other thread, by invoking the {@link ThreadGroup#uncaughtException
* uncaughtException} method of the thread's {@link
* ThreadGroup} object. The default implementation of this method
* prints the exception's stack trace to {@link System#err} and
* terminates the thread; it does not cause the virtual machine to exit or
* halt.
*
*
In rare circumstances the virtual machine may abort, that is,
* stop running without shutting down cleanly. This occurs when the
* virtual machine is terminated externally, for example with the
* SIGKILL signal on Unix or the TerminateProcess call on
* Microsoft Windows. The virtual machine may also abort if a native method goes awry
* by, for example, corrupting internal data structures or attempting to
* access nonexistent memory. If the virtual machine aborts then no
* guarantee can be made about whether or not any shutdown hooks will be
* run.
*
* @param hook
* An initialized but unstarted {@link Thread} object
*
* @throws IllegalArgumentException
* If the specified hook has already been registered,
* or if it can be determined that the hook is already running or
* has already been run
*
* @throws IllegalStateException
* If the virtual machine is already in the process
* of shutting down
*
* @throws SecurityException
* If a security manager is present and it denies
* {@link RuntimePermission}("shutdownHooks")
*
* @see #removeShutdownHook
* @see #halt(int)
* @see #exit(int)
* @since 1.3
*/
public void addShutdownHook(java.lang.Thread hook) { }
/**
* De-registers a previously-registered virtual-machine shutdown hook.
*
* @param hook the hook to remove
* @return true if the specified hook had previously been
* registered and was successfully de-registered, false
* otherwise.
*
* @throws IllegalStateException
* If the virtual machine is already in the process of shutting
* down
*
* @throws SecurityException
* If a security manager is present and it denies
* {@link RuntimePermission}("shutdownHooks")
*
* @see #addShutdownHook
* @see #exit(int)
* @since 1.3
*/
public boolean removeShutdownHook(java.lang.Thread hook) {
return false;
}
/**
* Forcibly terminates the currently running Java virtual machine. This
* method never returns normally.
*
*
This method should be used with extreme caution. Unlike the
* {@link #exit exit} method, this method does not cause shutdown
* hooks to be started and does not run uninvoked finalizers if
* finalization-on-exit has been enabled. If the shutdown sequence has
* already been initiated then this method does not wait for any running
* shutdown hooks or finalizers to finish their work.
*
* If process model exists, Runtime.halt() must rely on the process
* exiting to release resources.
*
* If process model does not exist, and a security manager exists,
* the security manager by default must prohibit calls to Runtime.halt()
* by throwing SecurityException. Otherwise, the system will hang
* indefinitely when called.
*
*
* @param status
* Termination status. By convention, a nonzero status code
* indicates abnormal termination. If the {@link Runtime#exit
* exit} (equivalently, {@link System#exit(int)
* System.exit}) method has already been invoked then this
* status code will override the status code passed to that method.
*
* @throws SecurityException
* If a security manager is present and its {@link
* SecurityManager#checkExit checkExit} method does not permit
* an exit with the specified status
*
* @see #exit
* @see #addShutdownHook
* @see #removeShutdownHook
* @since 1.3
*/
public void halt(int status) { }
/**
* Executes the specified string command in a separate process.
*
* The command argument is parsed into tokens and then
* executed as a command in a separate process. The token parsing is
* done by a {@link java.util.StringTokenizer} created by the call:
*
* new StringTokenizer(command)
*
* with no further modifications of the character categories.
* This method has exactly the same effect as
* exec(command, null).
*
* If process model exists, Runtime.exec() must behave as it
* does in the J2SE specification.
*
* If process model does not exist, Runtime.exec() and all
* java.lang.Process methods must throw SecurityException.
*
*
* @param command a specified system command.
* @return a Process object for managing the subprocess.
* @exception SecurityException if a security manager exists and its
* checkExec method doesn't allow creation of a subprocess.
* @exception IOException if an I/O error occurs
* @exception NullPointerException if command is
* null
* @exception IllegalArgumentException if command is empty
*
* @see java.lang.Runtime#exec(java.lang.String, java.lang.String[])
* @see java.lang.SecurityManager#checkExec(java.lang.String)
*/
public java.lang.Process exec(java.lang.String command) throws IOException {
return null;
}
/**
* Executes the specified string command in a separate process with the
* specified environment.
*
* This method breaks the command string into tokens and
* creates a new array cmdarray containing the tokens in the
* order that they were produced by the string tokenizer; it
* then performs the call exec(cmdarray, envp). The token
* parsing is done by a {@link java.util.StringTokenizer} created by
* the call:
*
* new StringTokenizer(command)
*
* with no further modification of the character categories.
*
*
* The environment variable settings are specified by envp.
* If envp is null, the subprocess inherits the
* environment settings of the current process.
*
* If process model exists, Runtime.exec() must behave as it
* does in the J2SE specification.
*
* If process model does not exist, Runtime.exec() and all
* java.lang.Process methods must throw SecurityException.
*
*
* @param cmd a specified system command.
* @param envp array of strings, each element of which
* has environment variable settings in format
* name=value.
* @return a Process object for managing the subprocess.
* @exception SecurityException if a security manager exists and its
* checkExec method doesn't allow creation of a subprocess.
* @exception IOException if an I/O error occurs
* @exception NullPointerException if cmd is null
* @exception IllegalArgumentException if cmd is empty
* @see java.lang.Runtime#exec(java.lang.String[])
* @see java.lang.Runtime#exec(java.lang.String[], java.lang.String[])
* @see java.lang.SecurityManager#checkExec(java.lang.String)
*/
public java.lang.Process exec(java.lang.String cmd, java.lang.String[] envp)
throws IOException
{
return null;
}
/**
* Executes the specified string command in a separate process with the
* specified environment and working directory.
*
* This method breaks the command string into tokens and
* creates a new array cmdarray containing the tokens in the
* order that they were produced by the string tokenizer; it
* then performs the call exec(cmdarray, envp). The token
* parsing is done by a {@link java.util.StringTokenizer} created by
* the call:
*
* new StringTokenizer(command)
*
* with no further modification of the character categories.
*
*
* The environment variable settings are specified by envp.
* If envp is null, the subprocess inherits the
* environment settings of the current process.
*
*
* The working directory of the new subprocess is specified by dir.
* If dir is null, the subprocess inherits the
* current working directory of the current process.
*
*
* If process model exists, Runtime.exec() must behave as it
* does in the J2SE specification.
*
* If process model does not exist, Runtime.exec() and all
* java.lang.Process methods must throw SecurityException.
*
*
* @param command a specified system command.
* @param envp array of strings, each element of which
* has environment variable settings in format
* name=value.
* @param dir the working directory of the subprocess, or
* null if the subprocess should inherit
* the working directory of the current process.
* @return a Process object for managing the subprocess.
* @exception SecurityException if a security manager exists and its
* checkExec method doesn't allow creation of a subprocess.
* @exception IOException if an I/O error occurs
* @exception NullPointerException if command is
* null
* @exception IllegalArgumentException if command is empty
* @see java.lang.Runtime#exec(java.lang.String[], java.lang.String[], File)
* @see java.lang.SecurityManager#checkExec(java.lang.String)
* @since 1.3
*/
public java.lang.Process exec(java.lang.String command, java.lang.String[]
envp, File dir) throws IOException
{
return null;
}
/**
* Executes the specified command and arguments in a separate process.
*
* The command specified by the tokens in cmdarray is
* executed as a command in a separate process. This has exactly the
* same effect as exec(cmdarray, null).
*
* If there is a security manager, its checkExec
* method is called with the first component of the array
* cmdarray as its argument. This may result in a security
* exception.
*
*
* If process model exists, Runtime.exec() must behave as it
* does in the J2SE specification.
*
* If process model does not exist, Runtime.exec() and all
* java.lang.Process methods must throw SecurityException.
*
*
* @param cmdarray array containing the command to call and
* its arguments.
* @return a Process object for managing the subprocess.
* @exception SecurityException if a security manager exists and its
* checkExec method doesn't allow creation of a subprocess.
* @exception IOException if an I/O error occurs
* @exception NullPointerException if cmdarray is
* null
* @exception IndexOutOfBoundsException if cmdarray is an
* empty array (has length 0).
* @see java.lang.Runtime#exec(java.lang.String[], java.lang.String[])
* @see java.lang.SecurityManager#checkExec(java.lang.String)
*/
public java.lang.Process exec(java.lang.String[] cmdarray)
throws IOException
{
return null;
}
/**
* Executes the specified command and arguments in a separate process
* with the specified environment.
*
* Given an array of strings cmdarray, representing the
* tokens of a command line, and an array of strings envp,
* representing "environment" variable settings, this method creates
* a new process in which to execute the specified command.
*
*
* If envp is null, the subprocess inherits the
* environment settings of the current process.
*
*
* If process model exists, Runtime.exec() must behave as it
* does in the J2SE specification.
*
* If process model does not exist, Runtime.exec() and all
* java.lang.Process methods must throw SecurityException.
*
*
* @param cmdarray array containing the command to call and
* its arguments.
* @param envp array of strings, each element of which
* has environment variable settings in format
* name=value.
* @return a Process object for managing the subprocess.
* @exception SecurityException if a security manager exists and its
* checkExec method doesn't allow creation of a subprocess.
* @exception IOException if an I/O error occurs
* @exception NullPointerException if cmdarray is
* null
* @exception IndexOutOfBoundsException if cmdarray is an
* empty array (has length 0).
* @see java.lang.Process
* @see java.lang.SecurityException
* @see java.lang.SecurityManager#checkExec(java.lang.String)
*/
public java.lang.Process exec(java.lang.String[] cmdarray,
java.lang.String[] envp) throws IOException
{
return null;
}
/**
* Executes the specified command and arguments in a separate process with
* the specified environment and working directory.
*
* If there is a security manager, its checkExec
* method is called with the first component of the array
* cmdarray as its argument. This may result in a security
* exception.
*
* Given an array of strings cmdarray, representing the
* tokens of a command line, and an array of strings envp,
* representing "environment" variable settings, this method creates
* a new process in which to execute the specified command.
*
*
* If envp is null, the subprocess inherits the
* environment settings of the current process.
*
*
* The working directory of the new subprocess is specified by dir.
* If dir is null, the subprocess inherits the
* current working directory of the current process.
*
*
*
* If process model exists, Runtime.exec() must behave as it
* does in the J2SE specification.
*
* If process model does not exist, Runtime.exec() and all
* java.lang.Process methods must throw SecurityException.
*
*
* @param cmdarray array containing the command to call and
* its arguments.
* @param envp array of strings, each element of which
* has environment variable settings in format
* name=value.
* @param dir the working directory of the subprocess, or
* null if the subprocess should inherit
* the working directory of the current process.
* @return a Process object for managing the subprocess.
* @exception SecurityException if a security manager exists and its
* checkExec method doesn't allow creation of a
* subprocess.
* @exception NullPointerException if cmdarray is
* null
* @exception IndexOutOfBoundsException if cmdarray is an
* empty array (has length 0).
* @exception IOException if an I/O error occurs.
* @see java.lang.Process
* @see java.lang.SecurityException
* @see java.lang.SecurityManager#checkExec(java.lang.String)
* @since 1.3
*/
public java.lang.Process exec(java.lang.String[] cmdarray,
java.lang.String[] envp, File dir) throws IOException
{
return null;
}
/**
* Returns the number of processors available to the Java virtual machine.
*
*
This value may change during a particular invocation of the virtual
* machine. Applications that are sensitive to the number of available
* processors should therefore occasionally poll this property and adjust
* their resource usage appropriately.
*
* @return the maximum number of processors available to the virtual
* machine; never smaller than one
*/
public int availableProcessors() {
return 0;
}
/**
* Returns the amount of free memory in the Java Virtual Machine.
* Calling the
* gc method may result in increasing the value returned
* by freeMemory.
*
* @return an approximation to the total amount of memory currently
* available for future allocated objects, measured in bytes.
*/
public long freeMemory() {
return -1;
}
/**
* Returns the total amount of memory in the Java virtual machine.
* The value returned by this method may vary over time, depending on
* the host environment.
*
* Note that the amount of memory required to hold an object of any
* given type may be implementation-dependent.
*
* @return the total amount of memory currently available for current
* and future objects, measured in bytes.
*/
public long totalMemory() {
return -1;
}
/**
* Returns the maximum amount of memory that the Java virtual machine will
* attempt to use. If there is no inherent limit then the value {@link
* java.lang.Long#MAX_VALUE} will be returned.
*
* @return the maximum amount of memory that the virtual machine will
* attempt to use, measured in bytes
*/
public long maxMemory() {
return -1;
}
/**
* Runs the garbage collector.
* Calling this method suggests that the Java virtual machine expend
* effort toward recycling unused objects in order to make the memory
* they currently occupy available for quick reuse. When control
* returns from the method call, the virtual machine has made
* its best effort to recycle all discarded objects.
*
* The name gc stands for "garbage
* collector". The virtual machine performs this recycling
* process automatically as needed, in a separate thread, even if the
* gc method is not invoked explicitly.
*
* The method {@link System#gc()} is the conventional and convenient
* means of invoking this method.
*/
public void gc() { }
/**
* Runs the finalization methods of any objects pending finalization.
* Calling this method suggests that the Java virtual machine expend
* effort toward running the finalize methods of objects
* that have been found to be discarded but whose finalize
* methods have not yet been run. When control returns from the
* method call, the virtual machine has made a best effort to
* complete all outstanding finalizations.
*
* The virtual machine performs the finalization process
* automatically as needed, in a separate thread, if the
* runFinalization method is not invoked explicitly.
*
* The method {@link System#runFinalization()} is the conventional
* and convenient means of invoking this method.
*
* @see java.lang.Object#finalize()
*/
public void runFinalization() { }
/**
* Enables/Disables tracing of instructions.
* If the boolean argument is true, this
* method suggests that the Java virtual machine emit debugging
* information for each instruction in the virtual machine as it
* is executed. The format of this information, and the file or other
* output stream to which it is emitted, depends on the host environment.
* The virtual machine may ignore this request if it does not support
* this feature. The destination of the trace output is system
* dependent.
*
* If the boolean argument is false, this
* method causes the virtual machine to stop performing the
* detailed instruction trace it is performing.
*
* @param on true to enable instruction tracing;
* false to disable this feature.
*/
public void traceInstructions(boolean on) { }
/**
* Enables/Disables tracing of method calls.
* If the boolean argument is true, this
* method suggests that the Java virtual machine emit debugging
* information for each method in the virtual machine as it is
* called. The format of this information, and the file or other output
* stream to which it is emitted, depends on the host environment. The
* virtual machine may ignore this request if it does not support
* this feature.
*
* Calling this method with argument false suggests that the
* virtual machine cease emitting per-call debugging information.
*
* @param on true to enable instruction tracing;
* false to disable this feature.
*/
public void traceMethodCalls(boolean on) { }
/**
* Loads the specified filename as a dynamic library. The filename
* argument must be a complete path name.
* From java_g it will automagically insert "_g" before the
* ".so" (for example
* Runtime.getRuntime().load("/home/avh/lib/libX11.so");).
*
* First, if there is a security manager, its checkLink
* method is called with the filename as its argument.
* This may result in a security exception.
*
* This is similar to the method {@link #loadLibrary(String)}, but it
* accepts a general file name as an argument rather than just a library
* name, allowing any file of native code to be loaded.
*
* The method {@link System#load(String)} is the conventional and
* convenient means of invoking this method.
*
* @param filename the file to load.
* @exception SecurityException if a security manager exists and its
* checkLink method doesn't allow
* loading of the specified dynamic library
* @exception UnsatisfiedLinkError if the file does not exist.
* @see java.lang.Runtime#getRuntime()
* @see java.lang.SecurityException
* @see java.lang.SecurityManager#checkLink(java.lang.String)
*/
public void load(java.lang.String filename) { }
/**
* Loads the dynamic library with the specified library name.
* A file containing native code is loaded from the local file system
* from a place where library files are conventionally obtained. The
* details of this process are implementation-dependent. The
* mapping from a library name to a specific filename is done in a
* system-specific manner.
*
* First, if there is a security manager, its checkLink
* method is called with the libname as its argument.
* This may result in a security exception.
*
* The method {@link System#loadLibrary(String)} is the conventional
* and convenient means of invoking this method. If native
* methods are to be used in the implementation of a class, a standard
* strategy is to put the native code in a library file (call it
* LibFile) and then to put a static initializer:
*
* static { System.loadLibrary("LibFile"); }
*
* within the class declaration. When the class is loaded and
* initialized, the necessary native code implementation for the native
* methods will then be loaded as well.
*
* If this method is called more than once with the same library
* name, the second and subsequent calls are ignored.
*
* @param libname the name of the library.
* @exception SecurityException if a security manager exists and its
* checkLink method doesn't allow
* loading of the specified dynamic library
* @exception UnsatisfiedLinkError if the library does not exist.
* @see java.lang.SecurityException
* @see java.lang.SecurityManager#checkLink(java.lang.String)
*/
public void loadLibrary(java.lang.String libname) { }
}