* An application cannot create its own instance of this class. * * @author unascribed * @see java.lang.Runtime#getRuntime() * @since 1.0 */ public class Runtime { private static final Runtime currentRuntime = new Runtime(); private static Version version; /** * Returns the runtime object associated with the current Java application. * Most of the methods of class {@code Runtime} are instance * methods and must be invoked with respect to the current runtime object. * * @return the {@code Runtime} object associated with the current * Java application. */ public static Runtime getRuntime() { return currentRuntime; } /** Don't let anyone else instantiate this class */ private Runtime() {} /** * 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 {@link #runFinalizersOnExit 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. * * @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 #runFinalizersOnExit * @see #halt(int) */ public void exit(int status) { SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkExit(status); } Shutdown.exit(status); } /** * Registers a new virtual-machine shutdown hook. * *
The Java virtual machine shuts down in response to two kinds * of events: * *
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. Attempts to use other thread-based * services such as the AWT event-dispatch thread, for example, may lead to * deadlocks. * *
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 * {@code SIGKILL} signal on Unix or the {@code 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(Thread hook) { SecurityManager sm = System.getSecurityManager(); if (sm != null) { sm.checkPermission(new RuntimePermission("shutdownHooks")); } ApplicationShutdownHooks.add(hook); } /** * De-registers a previously-registered virtual-machine shutdown hook. * * @param hook the hook to remove * @return {@code true} if the specified hook had previously been * registered and was successfully de-registered, {@code 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(Thread hook) { SecurityManager sm = System.getSecurityManager(); if (sm != null) { sm.checkPermission(new RuntimePermission("shutdownHooks")); } return ApplicationShutdownHooks.remove(hook); } /** * 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. * * @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) { SecurityManager sm = System.getSecurityManager(); if (sm != null) { sm.checkExit(status); } Shutdown.halt(status); } /** * Enable or disable finalization on exit; doing so specifies that the * finalizers of all objects that have finalizers that have not yet been * automatically invoked are to be run before the Java runtime exits. * By default, finalization on exit is disabled. * *
If there is a security manager, * its {@code checkExit} method is first called * with 0 as its argument to ensure the exit is allowed. * This could result in a SecurityException. * * @param value true to enable finalization on exit, false to disable * @deprecated This method is inherently unsafe. It may result in * finalizers being called on live objects while other threads are * concurrently manipulating those objects, resulting in erratic * behavior or deadlock. * This method is subject to removal in a future version of Java SE. * * @throws SecurityException * if a security manager exists and its {@code checkExit} * method doesn't allow the exit. * * @see java.lang.Runtime#exit(int) * @see java.lang.Runtime#gc() * @see java.lang.SecurityManager#checkExit(int) * @since 1.1 */ @Deprecated(since="1.2", forRemoval=true) public static void runFinalizersOnExit(boolean value) { SecurityManager security = System.getSecurityManager(); if (security != null) { try { security.checkExit(0); } catch (SecurityException e) { throw new SecurityException("runFinalizersOnExit"); } } Shutdown.setRunFinalizersOnExit(value); } /** * Executes the specified string command in a separate process. * *
This is a convenience method. An invocation of the form * {@code exec(command)} * behaves in exactly the same way as the invocation * {@link #exec(String, String[], File) exec}{@code (command, null, null)}. * * @param command a specified system command. * * @return A new {@link Process} object for managing the subprocess * * @throws SecurityException * If a security manager exists and its * {@link SecurityManager#checkExec checkExec} * method doesn't allow creation of the subprocess * * @throws IOException * If an I/O error occurs * * @throws NullPointerException * If {@code command} is {@code null} * * @throws IllegalArgumentException * If {@code command} is empty * * @see #exec(String[], String[], File) * @see ProcessBuilder */ public Process exec(String command) throws IOException { return exec(command, null, null); } /** * Executes the specified string command in a separate process with the * specified environment. * *
This is a convenience method. An invocation of the form * {@code exec(command, envp)} * behaves in exactly the same way as the invocation * {@link #exec(String, String[], File) exec}{@code (command, envp, null)}. * * @param command a specified system command. * * @param envp array of strings, each element of which * has environment variable settings in the format * name=value, or * {@code null} if the subprocess should inherit * the environment of the current process. * * @return A new {@link Process} object for managing the subprocess * * @throws SecurityException * If a security manager exists and its * {@link SecurityManager#checkExec checkExec} * method doesn't allow creation of the subprocess * * @throws IOException * If an I/O error occurs * * @throws NullPointerException * If {@code command} is {@code null}, * or one of the elements of {@code envp} is {@code null} * * @throws IllegalArgumentException * If {@code command} is empty * * @see #exec(String[], String[], File) * @see ProcessBuilder */ public Process exec(String command, String[] envp) throws IOException { return exec(command, envp, null); } /** * Executes the specified string command in a separate process with the * specified environment and working directory. * *
This is a convenience method. An invocation of the form * {@code exec(command, envp, dir)} * behaves in exactly the same way as the invocation * {@link #exec(String[], String[], File) exec}{@code (cmdarray, envp, dir)}, * where {@code cmdarray} is an array of all the tokens in * {@code command}. * *
More precisely, the {@code command} string is broken * into tokens using a {@link StringTokenizer} created by the call * {@code new {@link StringTokenizer}(command)} with no * further modification of the character categories. The tokens * produced by the tokenizer are then placed in the new string * array {@code cmdarray}, in the same order. * * @param command a specified system command. * * @param envp array of strings, each element of which * has environment variable settings in the format * name=value, or * {@code null} if the subprocess should inherit * the environment of the current process. * * @param dir the working directory of the subprocess, or * {@code null} if the subprocess should inherit * the working directory of the current process. * * @return A new {@link Process} object for managing the subprocess * * @throws SecurityException * If a security manager exists and its * {@link SecurityManager#checkExec checkExec} * method doesn't allow creation of the subprocess * * @throws IOException * If an I/O error occurs * * @throws NullPointerException * If {@code command} is {@code null}, * or one of the elements of {@code envp} is {@code null} * * @throws IllegalArgumentException * If {@code command} is empty * * @see ProcessBuilder * @since 1.3 */ public Process exec(String command, String[] envp, File dir) throws IOException { if (command.length() == 0) throw new IllegalArgumentException("Empty command"); StringTokenizer st = new StringTokenizer(command); String[] cmdarray = new String[st.countTokens()]; for (int i = 0; st.hasMoreTokens(); i++) cmdarray[i] = st.nextToken(); return exec(cmdarray, envp, dir); } /** * Executes the specified command and arguments in a separate process. * *
This is a convenience method. An invocation of the form * {@code exec(cmdarray)} * behaves in exactly the same way as the invocation * {@link #exec(String[], String[], File) exec}{@code (cmdarray, null, null)}. * * @param cmdarray array containing the command to call and * its arguments. * * @return A new {@link Process} object for managing the subprocess * * @throws SecurityException * If a security manager exists and its * {@link SecurityManager#checkExec checkExec} * method doesn't allow creation of the subprocess * * @throws IOException * If an I/O error occurs * * @throws NullPointerException * If {@code cmdarray} is {@code null}, * or one of the elements of {@code cmdarray} is {@code null} * * @throws IndexOutOfBoundsException * If {@code cmdarray} is an empty array * (has length {@code 0}) * * @see ProcessBuilder */ public Process exec(String cmdarray[]) throws IOException { return exec(cmdarray, null, null); } /** * Executes the specified command and arguments in a separate process * with the specified environment. * *
This is a convenience method. An invocation of the form * {@code exec(cmdarray, envp)} * behaves in exactly the same way as the invocation * {@link #exec(String[], String[], File) exec}{@code (cmdarray, envp, null)}. * * @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 the format * name=value, or * {@code null} if the subprocess should inherit * the environment of the current process. * * @return A new {@link Process} object for managing the subprocess * * @throws SecurityException * If a security manager exists and its * {@link SecurityManager#checkExec checkExec} * method doesn't allow creation of the subprocess * * @throws IOException * If an I/O error occurs * * @throws NullPointerException * If {@code cmdarray} is {@code null}, * or one of the elements of {@code cmdarray} is {@code null}, * or one of the elements of {@code envp} is {@code null} * * @throws IndexOutOfBoundsException * If {@code cmdarray} is an empty array * (has length {@code 0}) * * @see ProcessBuilder */ public Process exec(String[] cmdarray, String[] envp) throws IOException { return exec(cmdarray, envp, null); } /** * Executes the specified command and arguments in a separate process with * the specified environment and working directory. * *
Given an array of strings {@code cmdarray}, representing the * tokens of a command line, and an array of strings {@code envp}, * representing "environment" variable settings, this method creates * a new process in which to execute the specified command. * *
This method checks that {@code cmdarray} is a valid operating * system command. Which commands are valid is system-dependent, * but at the very least the command must be a non-empty list of * non-null strings. * *
If {@code envp} is {@code null}, the subprocess inherits the * environment settings of the current process. * *
A minimal set of system dependent environment variables may * be required to start a process on some operating systems. * As a result, the subprocess may inherit additional environment variable * settings beyond those in the specified environment. * *
{@link ProcessBuilder#start()} is now the preferred way to * start a process with a modified environment. * *
The working directory of the new subprocess is specified by {@code dir}. * If {@code dir} is {@code null}, the subprocess inherits the * current working directory of the current process. * *
If a security manager exists, its * {@link SecurityManager#checkExec checkExec} * method is invoked with the first component of the array * {@code cmdarray} as its argument. This may result in a * {@link SecurityException} being thrown. * *
Starting an operating system process is highly system-dependent. * Among the many things that can go wrong are: *
In such cases an exception will be thrown. The exact nature * of the exception is system-dependent, but it will always be a * subclass of {@link IOException}. * *
If the operating system does not support the creation of * processes, an {@link UnsupportedOperationException} will be thrown. * * * @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 the format * name=value, or * {@code null} if the subprocess should inherit * the environment of the current process. * * @param dir the working directory of the subprocess, or * {@code null} if the subprocess should inherit * the working directory of the current process. * * @return A new {@link Process} object for managing the subprocess * * @throws SecurityException * If a security manager exists and its * {@link SecurityManager#checkExec checkExec} * method doesn't allow creation of the subprocess * * @throws UnsupportedOperationException * If the operating system does not support the creation of processes. * * @throws IOException * If an I/O error occurs * * @throws NullPointerException * If {@code cmdarray} is {@code null}, * or one of the elements of {@code cmdarray} is {@code null}, * or one of the elements of {@code envp} is {@code null} * * @throws IndexOutOfBoundsException * If {@code cmdarray} is an empty array * (has length {@code 0}) * * @see ProcessBuilder * @since 1.3 */ public Process exec(String[] cmdarray, String[] envp, File dir) throws IOException { return new ProcessBuilder(cmdarray) .environment(envp) .directory(dir) .start(); } /** * 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 * @since 1.4 */ public native int availableProcessors(); /** * Returns the amount of free memory in the Java Virtual Machine. * Calling the * {@code gc} method may result in increasing the value returned * by {@code freeMemory.} * * @return an approximation to the total amount of memory currently * available for future allocated objects, measured in bytes. */ public native long freeMemory(); /** * 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 native long totalMemory(); /** * 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 * @since 1.4 */ public native long maxMemory(); /** * 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 {@code gc} stands for "garbage * collector". The virtual machine performs this recycling * process automatically as needed, in a separate thread, even if the * {@code gc} method is not invoked explicitly. *
* The method {@link System#gc()} is the conventional and convenient * means of invoking this method. */ public native void gc(); /* Wormhole for calling java.lang.ref.Finalizer.runFinalization */ private static native void runFinalization0(); /** * Runs the finalization methods of any objects pending finalization. * Calling this method suggests that the Java virtual machine expend * effort toward running the {@code finalize} methods of objects * that have been found to be discarded but whose {@code 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 * {@code 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() { runFinalization0(); } /** * Not implemented, does nothing. * * @deprecated * This method was intended to control instruction tracing. * It has been superseded by JVM-specific tracing mechanisms. * * @param on ignored */ @Deprecated(since="9", forRemoval=true) public void traceInstructions(boolean on) { } /** * Not implemented, does nothing. * * @deprecated * This method was intended to control method call tracing. * It has been superseded by JVM-specific tracing mechanisms. * * @param on ignored */ @Deprecated(since="9", forRemoval=true) public void traceMethodCalls(boolean on) { } /** * Loads the native library specified by the filename argument. The filename * argument must be an absolute path name. * (for example * {@code Runtime.getRuntime().load("/home/avh/lib/libX11.so");}). * * If the filename argument, when stripped of any platform-specific library * prefix, path, and file extension, indicates a library whose name is, * for example, L, and a native library called L is statically linked * with the VM, then the JNI_OnLoad_L function exported by the library * is invoked rather than attempting to load a dynamic library. * A filename matching the argument does not have to exist in the file * system. See the JNI Specification for more details. * * Otherwise, the filename argument is mapped to a native library image in * an implementation-dependent manner. *
* First, if there is a security manager, its {@code checkLink} * method is called with the {@code 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 * {@code checkLink} method doesn't allow * loading of the specified dynamic library * @exception UnsatisfiedLinkError if either the filename is not an * absolute path name, the native library is not statically * linked with the VM, or the library cannot be mapped to * a native library image by the host system. * @exception NullPointerException if {@code filename} is * {@code null} * @see java.lang.Runtime#getRuntime() * @see java.lang.SecurityException * @see java.lang.SecurityManager#checkLink(java.lang.String) */ @CallerSensitive public void load(String filename) { load0(Reflection.getCallerClass(), filename); } synchronized void load0(Class fromClass, String filename) { SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkLink(filename); } if (!(new File(filename).isAbsolute())) { throw new UnsatisfiedLinkError( "Expecting an absolute path of the library: " + filename); } ClassLoader.loadLibrary(fromClass, filename, true); } /** * Loads the native library specified by the {@code libname} * argument. The {@code libname} argument must not contain any platform * specific prefix, file extension or path. If a native library * called {@code libname} is statically linked with the VM, then the * JNI_OnLoad_{@code libname} function exported by the library is invoked. * See the JNI Specification for more details. * * Otherwise, the libname argument is loaded from a system library * location and mapped to a native library image in an implementation- * dependent manner. *
* First, if there is a security manager, its {@code checkLink} * method is called with the {@code 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 * {@code LibFile}) and then to put a static initializer: *
* static { System.loadLibrary("LibFile"); }
* * 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 * {@code checkLink} method doesn't allow * loading of the specified dynamic library * @exception UnsatisfiedLinkError if either the libname argument * contains a file path, the native library is not statically * linked with the VM, or the library cannot be mapped to a * native library image by the host system. * @exception NullPointerException if {@code libname} is * {@code null} * @see java.lang.SecurityException * @see java.lang.SecurityManager#checkLink(java.lang.String) */ @CallerSensitive public void loadLibrary(String libname) { loadLibrary0(Reflection.getCallerClass(), libname); } synchronized void loadLibrary0(Class fromClass, String libname) { SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkLink(libname); } if (libname.indexOf((int)File.separatorChar) != -1) { throw new UnsatisfiedLinkError( "Directory separator should not appear in library name: " + libname); } ClassLoader.loadLibrary(fromClass, libname, false); } /** * Creates a localized version of an input stream. This method takes * an {@code InputStream} and returns an {@code InputStream} * equivalent to the argument in all respects except that it is * localized: as characters in the local character set are read from * the stream, they are automatically converted from the local * character set to Unicode. *
* If the argument is already a localized stream, it may be returned * as the result. * * @param in InputStream to localize * @return a localized input stream * @see java.io.InputStream * @see java.io.BufferedReader#BufferedReader(java.io.Reader) * @see java.io.InputStreamReader#InputStreamReader(java.io.InputStream) * @deprecated As of JDK 1.1, the preferred way to translate a byte * stream in the local encoding into a character stream in Unicode is via * the {@code InputStreamReader} and {@code BufferedReader} * classes. * This method is subject to removal in a future version of Java SE. */ @Deprecated(since="1.1", forRemoval=true) public InputStream getLocalizedInputStream(InputStream in) { return in; } /** * Creates a localized version of an output stream. This method * takes an {@code OutputStream} and returns an * {@code OutputStream} equivalent to the argument in all respects * except that it is localized: as Unicode characters are written to * the stream, they are automatically converted to the local * character set. *
* If the argument is already a localized stream, it may be returned * as the result. * * @deprecated As of JDK 1.1, the preferred way to translate a * Unicode character stream into a byte stream in the local encoding is via * the {@code OutputStreamWriter}, {@code BufferedWriter}, and * {@code PrintWriter} classes. * This method is subject to removal in a future version of Java SE. * * @param out OutputStream to localize * @return a localized output stream * @see java.io.OutputStream * @see java.io.BufferedWriter#BufferedWriter(java.io.Writer) * @see java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream) * @see java.io.PrintWriter#PrintWriter(java.io.OutputStream) */ @Deprecated(since="1.1", forRemoval=true) public OutputStream getLocalizedOutputStream(OutputStream out) { return out; } /** * Returns the version of the Java Runtime Environment as a {@link * Runtime.Version}. * * @return the {@link Runtime.Version} of the Java Runtime Environment * * @since 9 */ public static Version version() { if (version == null) { version = new Version(VersionProps.versionNumbers(), VersionProps.pre(), VersionProps.build(), VersionProps.optional()); } return version; } /** * A representation of a version string for an implementation of the * Java SE Platform. A version string contains a version number * optionally followed by pre-release and build information. * *
A version number, {@code $VNUM}, is a non-empty sequence * of elements separated by period characters (U+002E). An element is * either zero, or a unsigned integer numeral without leading zeros. The * final element in a version number must not be zero. The format is: *
* *
* ^[1-9][0-9]*(((\.0)*\.[1-9][0-9]*)*)*$
* The sequence may be of arbitrary length but the first three * elements are assigned specific meanings, as follows:
* *
* $MAJOR.$MINOR.$SECURITY
* {@code $MAJOR} --- The major version * number, incremented for a major release that contains significant new * features as specified in a new edition of the Java SE Platform * Specification, e.g., JSR 337 for * Java SE 8. Features may be removed in a major release, given * advance notice at least one major release ahead of time, and * incompatible changes may be made when justified. The {@code $MAJOR} * version number of JDK 8 is {@code 8}; the {@code $MAJOR} version * number of JDK 9 is {@code 9}. When {@code $MAJOR} is incremented, * all subsequent elements are removed.
{@code $MINOR} --- The minor version * number, incremented for a minor update release that may contain * compatible bug fixes, revisions to standard APIs mandated by a * Maintenance Release * of the relevant Platform Specification, and implementation features * outside the scope of that Specification such as new JDK-specific APIs, * additional service providers, new garbage collectors, and ports to new * hardware architectures.
{@code $SECURITY} --- The security * level, incremented for a security update release that contains critical * fixes including those necessary to improve security. {@code $SECURITY} * is not reset when {@code $MINOR} is incremented. A * higher value of {@code $SECURITY} for a given {@code $MAJOR} value, * therefore, always indicates a more secure release, regardless of the * value of {@code $MINOR}.
The fourth and later elements of a version number are free for use * by downstream consumers of this code base. Such a consumer may, * e.g., use the fourth element to identify patch releases which * contain a small number of critical non-security fixes in addition to * the security fixes in the corresponding security release.
* *The version number does not include trailing zero elements; * i.e., {@code $SECURITY} is omitted if it has the value zero, * and {@code $MINOR} is omitted if both {@code $MINOR} and {@code * $SECURITY} have the value zero.
* *The sequence of numerals in a version number is compared to another * such sequence in numerical, pointwise fashion; e.g., {@code * 9.9.1} is less than {@code 9.10.3}. If one sequence is shorter than * another then the missing elements of the shorter sequence are * considered to be less than the corresponding elements of the longer * sequence; e.g., {@code 9.1.2} is less than {@code 9.1.2.1}. *
* *A version string, {@code $VSTR}, consists of a version * number {@code $VNUM}, as described above, optionally followed by * pre-release and build information, in the format
* *
* $VNUM(-$PRE)?(\+($BUILD)?(-$OPT)?)?
* where:
* *{@code $PRE}, matching {@code ([a-zA-Z0-9]+)} * --- A pre-release identifier. Typically {@code ea}, for a * potentially unstable early-access release under active development, * or {@code internal}, for an internal developer build. * *
{@code $BUILD}, matching {@code * (0|[1-9][0-9]*)} --- The build number, incremented for each promoted * build. {@code $BUILD} is reset to {@code 1} when any portion of {@code * $VNUM} is incremented.
* *{@code $OPT}, matching {@code * ([-a-zA-Z0-9\.]+)} --- Additional build information, if desired. In * the case of an {@code internal} build this will often contain the date * and time of the build.
* *A version number {@code 10-ea} matches {@code $VNUM = "10"} and * {@code $PRE = "ea"}. The version number {@code 10+-ea} matches * {@code $VNUM = "10"} and {@code $OPT = "ea"}.
* *When comparing two version strings, the value of {@code $OPT}, if * present, may or may not be significant depending on the chosen * comparison method. The comparison methods {@link #compareTo(Version) * compareTo()} and {@link #compareToIgnoreOptional(Version) * compareToIgnoreOptional()} should be used consistently with the * corresponding methods {@link #equals(Object) equals()} and {@link * #equalsIgnoreOptional(Object) equalsIgnoreOptional()}.
* *A short version string, {@code $SVSTR}, often useful in * less formal contexts, is a version number optionally followed by a * pre-release identifier: * *
* $VNUM(-$PRE)?
* Each of the components in the version is * compared in the follow order of precedence: version numbers, * pre-release identifiers, build numbers, optional build information. *
* *Comparison begins by examining the sequence of version numbers. * If one sequence is shorter than another, then the missing elements * of the shorter sequence are considered to be less than the * corresponding elements of the longer sequence.
* *A version with a pre-release identifier is always considered to * be less than a version without one. Pre-release identifiers are * compared numerically when they consist only of digits, and * lexicographically otherwise. Numeric identifiers are considered to * be less than non-numeric identifiers.
* *A version without a build number is always less than one with a * build number; otherwise build numbers are compared numerically.
* *The optional build information is compared lexicographically. * During this comparison, a version with optional build information is * considered to be greater than a version without one.
* *A version is not comparable to any other type of object. * * @param ob * The object to be compared * * @return A negative integer, zero, or a positive integer if this * {@code Version} is less than, equal to, or greater than the * given {@code Version} * * @throws NullPointerException * If the given object is {@code null} */ @Override public int compareTo(Version ob) { return compare(ob, false); } /** * Compares this version to another disregarding optional build * information. * *
Two versions are compared by examining the version string as * described in {@link #compareTo(Version)} with the exception that the * optional build information is always ignored.
* * A version is not comparable to any other type of object.
*
* @param ob
* The object to be compared
*
* @return A negative integer, zero, or a positive integer if this
* {@code Version} is less than, equal to, or greater than the
* given {@code Version}
*
* @throws NullPointerException
* If the given object is {@code null}
*/
public int compareToIgnoreOptional(Version ob) {
return compare(ob, true);
}
private int compare(Version ob, boolean ignoreOpt) {
if (ob == null)
throw new NullPointerException("Invalid argument");
int ret = compareVersion(ob);
if (ret != 0)
return ret;
ret = comparePre(ob);
if (ret != 0)
return ret;
ret = compareBuild(ob);
if (ret != 0)
return ret;
if (!ignoreOpt)
return compareOptional(ob);
return 0;
}
private int compareVersion(Version ob) {
int size = version.size();
int oSize = ob.version().size();
int min = Math.min(size, oSize);
for (int i = 0; i < min; i++) {
Integer val = version.get(i);
Integer oVal = ob.version().get(i);
if (val != oVal)
return val - oVal;
}
if (size != oSize)
return size - oSize;
return 0;
}
private int comparePre(Version ob) {
Optional Two {@code Version}s are equal if and only if they represent the
* same version string.
*
* This method satisfies the general contract of the {@link
* Object#equals(Object) Object.equals} method. Two {@code Version}s are equal if and only if they represent the
* same version string disregarding the optional build information.
*
* @param ob
* The object to which this {@code Version} is to be compared
*
* @return {@code true} if, and only if, the given object is a {@code
* Version} that is identical to this {@code Version}
* ignoring the optinal build information
*
*/
public boolean equalsIgnoreOptional(Object ob) {
if (this == ob)
return true;
if (!(ob instanceof Version))
return false;
Version that = (Version)ob;
return (this.version().equals(that.version())
&& this.pre().equals(that.pre())
&& this.build().equals(that.build()));
}
/**
* Returns the hash code of this version.
*
* This method satisfies the general contract of the {@link
* Object#hashCode Object.hashCode} method.
*
* @return The hashcode of this version
*/
@Override
public int hashCode() {
int h = 1;
int p = 17;
h = p * h + version.hashCode();
h = p * h + pre.hashCode();
h = p * h + build.hashCode();
h = p * h + optional.hashCode();
return h;
}
}
private static class VersionBuilder {
// $VNUM(-$PRE)?(\+($BUILD)?(\-$OPT)?)?
// RE limits the format of version strings
// ([1-9][0-9]*(?:(?:\.0)*\.[1-9][0-9]*)*)(?:-([a-zA-Z0-9]+))?(?:(\+)(0|[1-9][0-9]*)?)?(?:-([-a-zA-Z0-9.]+))?
private static final String VNUM
= "(?[a-zA-Z0-9]+))?";
private static final String PRE_GROUP = "PRE";
private static final String BUILD
= "(?:(?