java.lang.Object
- org.apache.commons.lang3.SystemUtils

```
public class SystemUtils
extends java.lang.Object
```
Helpers for java.lang.System.

If a system property cannot be read due to security restrictions, the corresponding field in this class will be set to null and a message will be written to System.err.

#ThreadSafe#

Since:

1.0

Field Summary

Fields
Modifier and Type	Field	Description
`static java.lang.String`	`AWT_TOOLKIT`	The `awt.toolkit` System Property.
`static java.lang.String`	`FILE_ENCODING`	The `file.encoding` System Property.
`static java.lang.String`	`FILE_SEPARATOR`	Deprecated. Use `File.separator`, since it is guaranteed to be a string containing a single character and it does not require a privilege check.
`static boolean`	`IS_JAVA_1_1`	Is `true` if this is Java version 1.1 (also 1.1.x versions).
`static boolean`	`IS_JAVA_1_2`	Is `true` if this is Java version 1.2 (also 1.2.x versions).
`static boolean`	`IS_JAVA_1_3`	Is `true` if this is Java version 1.3 (also 1.3.x versions).
`static boolean`	`IS_JAVA_1_4`	Is `true` if this is Java version 1.4 (also 1.4.x versions).
`static boolean`	`IS_JAVA_1_5`	Is `true` if this is Java version 1.5 (also 1.5.x versions).
`static boolean`	`IS_JAVA_1_6`	Is `true` if this is Java version 1.6 (also 1.6.x versions).
`static boolean`	`IS_JAVA_1_7`	Is `true` if this is Java version 1.7 (also 1.7.x versions).
`static boolean`	`IS_JAVA_1_8`	Is `true` if this is Java version 1.8 (also 1.8.x versions).
`static boolean`	`IS_JAVA_1_9`	Deprecated. As of release 3.5, replaced by `IS_JAVA_9`
`static boolean`	`IS_JAVA_10`	Is `true` if this is Java version 10 (also 10.x versions).
`static boolean`	`IS_JAVA_11`	Is `true` if this is Java version 11 (also 11.x versions).
`static boolean`	`IS_JAVA_12`	Is `true` if this is Java version 12 (also 12.x versions).
`static boolean`	`IS_JAVA_13`	Is `true` if this is Java version 13 (also 13.x versions).
`static boolean`	`IS_JAVA_14`	Is `true` if this is Java version 14 (also 14.x versions).
`static boolean`	`IS_JAVA_15`	Is `true` if this is Java version 15 (also 15.x versions).
`static boolean`	`IS_JAVA_9`	Is `true` if this is Java version 9 (also 9.x versions).
`static boolean`	`IS_OS_400`	Is `true` if this is IBM OS/400.
`static boolean`	`IS_OS_AIX`	Is `true` if this is AIX.
`static boolean`	`IS_OS_FREE_BSD`	Is `true` if this is FreeBSD.
`static boolean`	`IS_OS_HP_UX`	Is `true` if this is HP-UX.
`static boolean`	`IS_OS_IRIX`	Is `true` if this is Irix.
`static boolean`	`IS_OS_LINUX`	Is `true` if this is Linux.
`static boolean`	`IS_OS_MAC`	Is `true` if this is Mac.
`static boolean`	`IS_OS_MAC_OSX`	Is `true` if this is Mac.
`static boolean`	`IS_OS_MAC_OSX_BIG_SUR`	Is `true` if this is Mac OS X Big Sur.
`static boolean`	`IS_OS_MAC_OSX_CATALINA`	Is `true` if this is Mac OS X Catalina.
`static boolean`	`IS_OS_MAC_OSX_CHEETAH`	Is `true` if this is Mac OS X Cheetah.
`static boolean`	`IS_OS_MAC_OSX_EL_CAPITAN`	Is `true` if this is Mac OS X El Capitan.
`static boolean`	`IS_OS_MAC_OSX_HIGH_SIERRA`	Is `true` if this is Mac OS X High Sierra.
`static boolean`	`IS_OS_MAC_OSX_JAGUAR`	Is `true` if this is Mac OS X Jaguar.
`static boolean`	`IS_OS_MAC_OSX_LEOPARD`	Is `true` if this is Mac OS X Leopard.
`static boolean`	`IS_OS_MAC_OSX_LION`	Is `true` if this is Mac OS X Lion.
`static boolean`	`IS_OS_MAC_OSX_MAVERICKS`	Is `true` if this is Mac OS X Mavericks.
`static boolean`	`IS_OS_MAC_OSX_MOJAVE`	Is `true` if this is Mac OS X Mojave.
`static boolean`	`IS_OS_MAC_OSX_MOUNTAIN_LION`	Is `true` if this is Mac OS X Mountain Lion.
`static boolean`	`IS_OS_MAC_OSX_PANTHER`	Is `true` if this is Mac OS X Panther.
`static boolean`	`IS_OS_MAC_OSX_PUMA`	Is `true` if this is Mac OS X Puma.
`static boolean`	`IS_OS_MAC_OSX_SIERRA`	Is `true` if this is Mac OS X Sierra.
`static boolean`	`IS_OS_MAC_OSX_SNOW_LEOPARD`	Is `true` if this is Mac OS X Snow Leopard.
`static boolean`	`IS_OS_MAC_OSX_TIGER`	Is `true` if this is Mac OS X Tiger.
`static boolean`	`IS_OS_MAC_OSX_YOSEMITE`	Is `true` if this is Mac OS X Yosemite.
`static boolean`	`IS_OS_NET_BSD`	Is `true` if this is NetBSD.
`static boolean`	`IS_OS_OPEN_BSD`	Is `true` if this is OpenBSD.
`static boolean`	`IS_OS_OS2`	Is `true` if this is OS/2.
`static boolean`	`IS_OS_SOLARIS`	Is `true` if this is Solaris.
`static boolean`	`IS_OS_SUN_OS`	Is `true` if this is SunOS.
`static boolean`	`IS_OS_UNIX`	Is `true` if this is a UNIX like system, as in any of AIX, HP-UX, Irix, Linux, MacOSX, Solaris or SUN OS.
`static boolean`	`IS_OS_WINDOWS`	Is `true` if this is Windows.
`static boolean`	`IS_OS_WINDOWS_10`	Is `true` if this is Windows 10.
`static boolean`	`IS_OS_WINDOWS_2000`	Is `true` if this is Windows 2000.
`static boolean`	`IS_OS_WINDOWS_2003`	Is `true` if this is Windows 2003.
`static boolean`	`IS_OS_WINDOWS_2008`	Is `true` if this is Windows Server 2008.
`static boolean`	`IS_OS_WINDOWS_2012`	Is `true` if this is Windows Server 2012.
`static boolean`	`IS_OS_WINDOWS_7`	Is `true` if this is Windows 7.
`static boolean`	`IS_OS_WINDOWS_8`	Is `true` if this is Windows 8.
`static boolean`	`IS_OS_WINDOWS_95`	Is `true` if this is Windows 95.
`static boolean`	`IS_OS_WINDOWS_98`	Is `true` if this is Windows 98.
`static boolean`	`IS_OS_WINDOWS_ME`	Is `true` if this is Windows ME.
`static boolean`	`IS_OS_WINDOWS_NT`	Is `true` if this is Windows NT.
`static boolean`	`IS_OS_WINDOWS_VISTA`	Is `true` if this is Windows Vista.
`static boolean`	`IS_OS_WINDOWS_XP`	Is `true` if this is Windows XP.
`static boolean`	`IS_OS_ZOS`	Is `true` if this is z/OS.
`static java.lang.String`	`JAVA_AWT_FONTS`	The `java.awt.fonts` System Property.
`static java.lang.String`	`JAVA_AWT_GRAPHICSENV`	The `java.awt.graphicsenv` System Property.
`static java.lang.String`	`JAVA_AWT_HEADLESS`	The `java.awt.headless` System Property.
`static java.lang.String`	`JAVA_AWT_PRINTERJOB`	The `java.awt.printerjob` System Property.
`static java.lang.String`	`JAVA_CLASS_PATH`	The `java.class.path` System Property.
`static java.lang.String`	`JAVA_CLASS_VERSION`	The `java.class.version` System Property.
`static java.lang.String`	`JAVA_COMPILER`	The `java.compiler` System Property.
`static java.lang.String`	`JAVA_ENDORSED_DIRS`	The `java.endorsed.dirs` System Property.
`static java.lang.String`	`JAVA_EXT_DIRS`	The `java.ext.dirs` System Property.
`static java.lang.String`	`JAVA_HOME`	The `java.home` System Property.
`static java.lang.String`	`JAVA_IO_TMPDIR`	The `java.io.tmpdir` System Property.
`static java.lang.String`	`JAVA_LIBRARY_PATH`	The `java.library.path` System Property.
`static java.lang.String`	`JAVA_RUNTIME_NAME`	The `java.runtime.name` System Property.
`static java.lang.String`	`JAVA_RUNTIME_VERSION`	The `java.runtime.version` System Property.
`static java.lang.String`	`JAVA_SPECIFICATION_NAME`	The `java.specification.name` System Property.
`static java.lang.String`	`JAVA_SPECIFICATION_VENDOR`	The `java.specification.vendor` System Property.
`static java.lang.String`	`JAVA_SPECIFICATION_VERSION`	The `java.specification.version` System Property.
`static java.lang.String`	`JAVA_UTIL_PREFS_PREFERENCES_FACTORY`	The `java.util.prefs.PreferencesFactory` System Property.
`static java.lang.String`	`JAVA_VENDOR`	The `java.vendor` System Property.
`static java.lang.String`	`JAVA_VENDOR_URL`	The `java.vendor.url` System Property.
`static java.lang.String`	`JAVA_VERSION`	The `java.version` System Property.
`static java.lang.String`	`JAVA_VM_INFO`	The `java.vm.info` System Property.
`static java.lang.String`	`JAVA_VM_NAME`	The `java.vm.name` System Property.
`static java.lang.String`	`JAVA_VM_SPECIFICATION_NAME`	The `java.vm.specification.name` System Property.
`static java.lang.String`	`JAVA_VM_SPECIFICATION_VENDOR`	The `java.vm.specification.vendor` System Property.
`static java.lang.String`	`JAVA_VM_SPECIFICATION_VERSION`	The `java.vm.specification.version` System Property.
`static java.lang.String`	`JAVA_VM_VENDOR`	The `java.vm.vendor` System Property.
`static java.lang.String`	`JAVA_VM_VERSION`	The `java.vm.version` System Property.
`static java.lang.String`	`LINE_SEPARATOR`	Deprecated. Use `System.lineSeparator()` instead, since it does not require a privilege check.
`static java.lang.String`	`OS_ARCH`	The `os.arch` System Property.
`static java.lang.String`	`OS_NAME`	The `os.name` System Property.
`static java.lang.String`	`OS_VERSION`	The `os.version` System Property.
`static java.lang.String`	`PATH_SEPARATOR`	Deprecated. Use `File.pathSeparator`, since it is guaranteed to be a string containing a single character and it does not require a privilege check.
`static java.lang.String`	`USER_COUNTRY`	The `user.country` or `user.region` System Property.
`static java.lang.String`	`USER_DIR`	The `user.dir` System Property.
`static java.lang.String`	`USER_HOME`	The `user.home` System Property.
`static java.lang.String`	`USER_LANGUAGE`	The `user.language` System Property.
`static java.lang.String`	`USER_NAME`	The `user.name` System Property.
`static java.lang.String`	`USER_TIMEZONE`	The `user.timezone` System Property.

Constructor Summary

Constructors
Constructor Description

SystemUtils()
SystemUtils instances should NOT be constructed in standard programming.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static java.lang.String`	`getEnvironmentVariable(java.lang.String name, java.lang.String defaultValue)`	Gets an environment variable, defaulting to `defaultValue` if the variable cannot be read.
`static java.lang.String`	`getHostName()`	Gets the host name from an environment variable (COMPUTERNAME on Windows, HOSTNAME elsewhere).
`static java.io.File`	`getJavaHome()`	Gets the Java home directory as a `File`.
`static java.io.File`	`getJavaIoTmpDir()`	Gets the Java IO temporary directory as a `File`.
`static java.io.File`	`getUserDir()`	Gets the user directory as a `File`.
`static java.io.File`	`getUserHome()`	Gets the user home directory as a `File`.
`static java.lang.String`	`getUserName()`	Gets the user name.
`static java.lang.String`	`getUserName(java.lang.String defaultValue)`	Gets the user name.
`static boolean`	`isJavaAwtHeadless()`	Returns whether the `JAVA_AWT_HEADLESS` value is `true`.
`static boolean`	`isJavaVersionAtLeast(JavaVersion requiredVersion)`	Is the Java version at least the requested version.
`static boolean`	`isJavaVersionAtMost(JavaVersion requiredVersion)`	Is the Java version at most the requested version.

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

- Field Detail
  - AWT_TOOLKIT
```
public static final java.lang.String AWT_TOOLKIT
```
    The awt.toolkit System Property.
    
    Holds a class name, on Windows XP this is sun.awt.windows.WToolkit.
    
    On platforms without a GUI, this value is null.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.1
  - FILE_ENCODING
```
public static final java.lang.String FILE_ENCODING
```
    The file.encoding System Property.
    
    File encoding, such as Cp1252.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.0, Java 1.2
  - FILE_SEPARATOR
```
@Deprecated
public static final java.lang.String FILE_SEPARATOR
```
    Deprecated.
    Use File.separator, since it is guaranteed to be a string containing a single character and it does not require a privilege check.
    The file.separator System Property. The file separator is:
    
    "/" on UNIX
    
    "\" on Windows.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    Since:
    
    Java 1.1
  - JAVA_AWT_FONTS
```
public static final java.lang.String JAVA_AWT_FONTS
```
    The java.awt.fonts System Property.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.1
  - JAVA_AWT_GRAPHICSENV
```
public static final java.lang.String JAVA_AWT_GRAPHICSENV
```
    The java.awt.graphicsenv System Property.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.1
  - JAVA_AWT_HEADLESS
```
public static final java.lang.String JAVA_AWT_HEADLESS
```
    The java.awt.headless System Property. The value of this property is the String "true" or "false".
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.1, Java 1.4
    
    See Also:
    
    isJavaAwtHeadless()
  - JAVA_AWT_PRINTERJOB
```
public static final java.lang.String JAVA_AWT_PRINTERJOB
```
    The java.awt.printerjob System Property.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.1
  - JAVA_CLASS_PATH
```
public static final java.lang.String JAVA_CLASS_PATH
```
    The java.class.path System Property. Java class path.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - JAVA_CLASS_VERSION
```
public static final java.lang.String JAVA_CLASS_VERSION
```
    The java.class.version System Property. Java class format version number.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - JAVA_COMPILER
```
public static final java.lang.String JAVA_COMPILER
```
    The java.compiler System Property. Name of JIT compiler to use. First in JDK version 1.2. Not used in Sun JDKs after 1.2.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.2. Not used in Sun versions after 1.2.
  - JAVA_ENDORSED_DIRS
```
public static final java.lang.String JAVA_ENDORSED_DIRS
```
    The java.endorsed.dirs System Property. Path of endorsed directory or directories.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.4
  - JAVA_EXT_DIRS
```
public static final java.lang.String JAVA_EXT_DIRS
```
    The java.ext.dirs System Property. Path of extension directory or directories.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.3
  - JAVA_HOME
```
public static final java.lang.String JAVA_HOME
```
    The java.home System Property. Java installation directory.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - JAVA_IO_TMPDIR
```
public static final java.lang.String JAVA_IO_TMPDIR
```
    The java.io.tmpdir System Property. Default temp file path.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.2
  - JAVA_LIBRARY_PATH
```
public static final java.lang.String JAVA_LIBRARY_PATH
```
    The java.library.path System Property. List of paths to search when loading libraries.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.2
  - JAVA_RUNTIME_NAME
```
public static final java.lang.String JAVA_RUNTIME_NAME
```
    The java.runtime.name System Property. Java Runtime Environment name.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.0, Java 1.3
  - JAVA_RUNTIME_VERSION
```
public static final java.lang.String JAVA_RUNTIME_VERSION
```
    The java.runtime.version System Property. Java Runtime Environment version.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.0, Java 1.3
  - JAVA_SPECIFICATION_NAME
```
public static final java.lang.String JAVA_SPECIFICATION_NAME
```
    The java.specification.name System Property. Java Runtime Environment specification name.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.2
  - JAVA_SPECIFICATION_VENDOR
```
public static final java.lang.String JAVA_SPECIFICATION_VENDOR
```
    The java.specification.vendor System Property. Java Runtime Environment specification vendor.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.2
  - JAVA_SPECIFICATION_VERSION
```
public static final java.lang.String JAVA_SPECIFICATION_VERSION
```
    The java.specification.version System Property. Java Runtime Environment specification version.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.3
  - JAVA_UTIL_PREFS_PREFERENCES_FACTORY
```
public static final java.lang.String JAVA_UTIL_PREFS_PREFERENCES_FACTORY
```
    The java.util.prefs.PreferencesFactory System Property. A class name.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.1, Java 1.4
  - JAVA_VENDOR
```
public static final java.lang.String JAVA_VENDOR
```
    The java.vendor System Property. Java vendor-specific string.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - JAVA_VENDOR_URL
```
public static final java.lang.String JAVA_VENDOR_URL
```
    The java.vendor.url System Property. Java vendor URL.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - JAVA_VERSION
```
public static final java.lang.String JAVA_VERSION
```
    The java.version System Property. Java version number.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - JAVA_VM_INFO
```
public static final java.lang.String JAVA_VM_INFO
```
    The java.vm.info System Property. Java Virtual Machine implementation info.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.0, Java 1.2
  - JAVA_VM_NAME
```
public static final java.lang.String JAVA_VM_NAME
```
    The java.vm.name System Property. Java Virtual Machine implementation name.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.2
  - JAVA_VM_SPECIFICATION_NAME
```
public static final java.lang.String JAVA_VM_SPECIFICATION_NAME
```
    The java.vm.specification.name System Property. Java Virtual Machine specification name.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.2
  - JAVA_VM_SPECIFICATION_VENDOR
```
public static final java.lang.String JAVA_VM_SPECIFICATION_VENDOR
```
    The java.vm.specification.vendor System Property. Java Virtual Machine specification vendor.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.2
  - JAVA_VM_SPECIFICATION_VERSION
```
public static final java.lang.String JAVA_VM_SPECIFICATION_VERSION
```
    The java.vm.specification.version System Property. Java Virtual Machine specification version.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.2
  - JAVA_VM_VENDOR
```
public static final java.lang.String JAVA_VM_VENDOR
```
    The java.vm.vendor System Property. Java Virtual Machine implementation vendor.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.2
  - JAVA_VM_VERSION
```
public static final java.lang.String JAVA_VM_VERSION
```
    The java.vm.version System Property. Java Virtual Machine implementation version.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.2
  - LINE_SEPARATOR
```
@Deprecated
public static final java.lang.String LINE_SEPARATOR
```
    Deprecated.
    Use System.lineSeparator() instead, since it does not require a privilege check.
    
    The line.separator System Property. Line separator ("\n" on UNIX).
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - OS_ARCH
```
public static final java.lang.String OS_ARCH
```
    The os.arch System Property. Operating system architecture.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - OS_NAME
```
public static final java.lang.String OS_NAME
```
    The os.name System Property. Operating system name.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - OS_VERSION
```
public static final java.lang.String OS_VERSION
```
    The os.version System Property. Operating system version.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - PATH_SEPARATOR
```
@Deprecated
public static final java.lang.String PATH_SEPARATOR
```
    Deprecated.
    Use File.pathSeparator, since it is guaranteed to be a string containing a single character and it does not require a privilege check.
    
    The path.separator System Property. Path separator (":" on UNIX).
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - USER_COUNTRY
```
public static final java.lang.String USER_COUNTRY
```
    The user.country or user.region System Property. User's country code, such as GB. First in Java version 1.2 as user.region. Renamed to user.country in 1.4
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.0, Java 1.2
  - USER_DIR
```
public static final java.lang.String USER_DIR
```
    The user.dir System Property. User's current working directory.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - USER_HOME
```
public static final java.lang.String USER_HOME
```
    The user.home System Property. User's home directory.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - USER_LANGUAGE
```
public static final java.lang.String USER_LANGUAGE
```
    The user.language System Property. User's language code, such as "en".
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.0, Java 1.2
  - USER_NAME
```
public static final java.lang.String USER_NAME
```
    The user.name System Property. User's account name.
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    Java 1.1
  - USER_TIMEZONE
```
public static final java.lang.String USER_TIMEZONE
```
    The user.timezone System Property. For example: "America/Los_Angeles".
    
    Defaults to null if the runtime does not have security access to read this property or the property does not exist.
    
    This value is initialized when the class is loaded. If System.setProperty(String,String) or System.setProperties(java.util.Properties) is called after this class is loaded, the value will be out of sync with that System property.
    
    Since:
    
    2.1
  - IS_JAVA_1_1
```
public static final boolean IS_JAVA_1_1
```
    Is true if this is Java version 1.1 (also 1.1.x versions).
    
    The field will return false if JAVA_VERSION is null.
  - IS_JAVA_1_2
```
public static final boolean IS_JAVA_1_2
```
    Is true if this is Java version 1.2 (also 1.2.x versions).
    
    The field will return false if JAVA_VERSION is null.
  - IS_JAVA_1_3
```
public static final boolean IS_JAVA_1_3
```
    Is true if this is Java version 1.3 (also 1.3.x versions).
    
    The field will return false if JAVA_VERSION is null.
  - IS_JAVA_1_4
```
public static final boolean IS_JAVA_1_4
```
    Is true if this is Java version 1.4 (also 1.4.x versions).
    
    The field will return false if JAVA_VERSION is null.
  - IS_JAVA_1_5
```
public static final boolean IS_JAVA_1_5
```
    Is true if this is Java version 1.5 (also 1.5.x versions).
    
    The field will return false if JAVA_VERSION is null.
  - IS_JAVA_1_6
```
public static final boolean IS_JAVA_1_6
```
    Is true if this is Java version 1.6 (also 1.6.x versions).
    
    The field will return false if JAVA_VERSION is null.
  - IS_JAVA_1_7
```
public static final boolean IS_JAVA_1_7
```
    Is true if this is Java version 1.7 (also 1.7.x versions).
    
    The field will return false if JAVA_VERSION is null.
    
    Since:
    
    3.0
  - IS_JAVA_1_8
```
public static final boolean IS_JAVA_1_8
```
    Is true if this is Java version 1.8 (also 1.8.x versions).
    
    The field will return false if JAVA_VERSION is null.
    
    Since:
    
    3.3.2
  - IS_JAVA_1_9
```
@Deprecated
public static final boolean IS_JAVA_1_9
```
    Deprecated.
    As of release 3.5, replaced by IS_JAVA_9
    
    Is true if this is Java version 1.9 (also 1.9.x versions).
    
    The field will return false if JAVA_VERSION is null.
    
    Since:
    
    3.4
  - IS_JAVA_9
```
public static final boolean IS_JAVA_9
```
    Is true if this is Java version 9 (also 9.x versions).
    
    The field will return false if JAVA_VERSION is null.
    
    Since:
    
    3.5
  - IS_JAVA_10
```
public static final boolean IS_JAVA_10
```
    Is true if this is Java version 10 (also 10.x versions).
    
    The field will return false if JAVA_VERSION is null.
    
    Since:
    
    3.7
  - IS_JAVA_11
```
public static final boolean IS_JAVA_11
```
    Is true if this is Java version 11 (also 11.x versions).
    
    The field will return false if JAVA_VERSION is null.
    
    Since:
    
    3.8
  - IS_JAVA_12
```
public static final boolean IS_JAVA_12
```
    Is true if this is Java version 12 (also 12.x versions).
    
    The field will return false if JAVA_VERSION is null.
    
    Since:
    
    3.9
  - IS_JAVA_13
```
public static final boolean IS_JAVA_13
```
    Is true if this is Java version 13 (also 13.x versions).
    
    The field will return false if JAVA_VERSION is null.
    
    Since:
    
    3.9
  - IS_JAVA_14
```
public static final boolean IS_JAVA_14
```
    Is true if this is Java version 14 (also 14.x versions).
    
    The field will return false if JAVA_VERSION is null.
    
    Since:
    
    3.10
  - IS_JAVA_15
```
public static final boolean IS_JAVA_15
```
    Is true if this is Java version 15 (also 15.x versions).
    
    The field will return false if JAVA_VERSION is null.
    
    Since:
    
    3.10
  - IS_OS_AIX
```
public static final boolean IS_OS_AIX
```
    Is true if this is AIX.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_HP_UX
```
public static final boolean IS_OS_HP_UX
```
    Is true if this is HP-UX.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_400
```
public static final boolean IS_OS_400
```
    Is true if this is IBM OS/400.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.3
  - IS_OS_IRIX
```
public static final boolean IS_OS_IRIX
```
    Is true if this is Irix.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_LINUX
```
public static final boolean IS_OS_LINUX
```
    Is true if this is Linux.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_MAC
```
public static final boolean IS_OS_MAC
```
    Is true if this is Mac.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_MAC_OSX
```
public static final boolean IS_OS_MAC_OSX
```
    Is true if this is Mac.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_MAC_OSX_CHEETAH
```
public static final boolean IS_OS_MAC_OSX_CHEETAH
```
    Is true if this is Mac OS X Cheetah.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.4
  - IS_OS_MAC_OSX_PUMA
```
public static final boolean IS_OS_MAC_OSX_PUMA
```
    Is true if this is Mac OS X Puma.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.4
  - IS_OS_MAC_OSX_JAGUAR
```
public static final boolean IS_OS_MAC_OSX_JAGUAR
```
    Is true if this is Mac OS X Jaguar.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.4
  - IS_OS_MAC_OSX_PANTHER
```
public static final boolean IS_OS_MAC_OSX_PANTHER
```
    Is true if this is Mac OS X Panther.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.4
  - IS_OS_MAC_OSX_TIGER
```
public static final boolean IS_OS_MAC_OSX_TIGER
```
    Is true if this is Mac OS X Tiger.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.4
  - IS_OS_MAC_OSX_LEOPARD
```
public static final boolean IS_OS_MAC_OSX_LEOPARD
```
    Is true if this is Mac OS X Leopard.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.4
  - IS_OS_MAC_OSX_SNOW_LEOPARD
```
public static final boolean IS_OS_MAC_OSX_SNOW_LEOPARD
```
    Is true if this is Mac OS X Snow Leopard.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.4
  - IS_OS_MAC_OSX_LION
```
public static final boolean IS_OS_MAC_OSX_LION
```
    Is true if this is Mac OS X Lion.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.4
  - IS_OS_MAC_OSX_MOUNTAIN_LION
```
public static final boolean IS_OS_MAC_OSX_MOUNTAIN_LION
```
    Is true if this is Mac OS X Mountain Lion.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.4
  - IS_OS_MAC_OSX_MAVERICKS
```
public static final boolean IS_OS_MAC_OSX_MAVERICKS
```
    Is true if this is Mac OS X Mavericks.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.4
  - IS_OS_MAC_OSX_YOSEMITE
```
public static final boolean IS_OS_MAC_OSX_YOSEMITE
```
    Is true if this is Mac OS X Yosemite.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.4
  - IS_OS_MAC_OSX_EL_CAPITAN
```
public static final boolean IS_OS_MAC_OSX_EL_CAPITAN
```
    Is true if this is Mac OS X El Capitan.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.5
  - IS_OS_MAC_OSX_SIERRA
```
public static final boolean IS_OS_MAC_OSX_SIERRA
```
    Is true if this is Mac OS X Sierra.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.12.0
  - IS_OS_MAC_OSX_HIGH_SIERRA
```
public static final boolean IS_OS_MAC_OSX_HIGH_SIERRA
```
    Is true if this is Mac OS X High Sierra.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.12.0
  - IS_OS_MAC_OSX_MOJAVE
```
public static final boolean IS_OS_MAC_OSX_MOJAVE
```
    Is true if this is Mac OS X Mojave.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.12.0
  - IS_OS_MAC_OSX_CATALINA
```
public static final boolean IS_OS_MAC_OSX_CATALINA
```
    Is true if this is Mac OS X Catalina.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.12.0
  - IS_OS_MAC_OSX_BIG_SUR
```
public static final boolean IS_OS_MAC_OSX_BIG_SUR
```
    Is true if this is Mac OS X Big Sur.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.12.0
  - IS_OS_FREE_BSD
```
public static final boolean IS_OS_FREE_BSD
```
    Is true if this is FreeBSD.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.1
  - IS_OS_OPEN_BSD
```
public static final boolean IS_OS_OPEN_BSD
```
    Is true if this is OpenBSD.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.1
  - IS_OS_NET_BSD
```
public static final boolean IS_OS_NET_BSD
```
    Is true if this is NetBSD.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.1
  - IS_OS_OS2
```
public static final boolean IS_OS_OS2
```
    Is true if this is OS/2.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_SOLARIS
```
public static final boolean IS_OS_SOLARIS
```
    Is true if this is Solaris.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_SUN_OS
```
public static final boolean IS_OS_SUN_OS
```
    Is true if this is SunOS.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_UNIX
```
public static final boolean IS_OS_UNIX
```
    Is true if this is a UNIX like system, as in any of AIX, HP-UX, Irix, Linux, MacOSX, Solaris or SUN OS.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.1
  - IS_OS_WINDOWS
```
public static final boolean IS_OS_WINDOWS
```
    Is true if this is Windows.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_WINDOWS_2000
```
public static final boolean IS_OS_WINDOWS_2000
```
    Is true if this is Windows 2000.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_WINDOWS_2003
```
public static final boolean IS_OS_WINDOWS_2003
```
    Is true if this is Windows 2003.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.1
  - IS_OS_WINDOWS_2008
```
public static final boolean IS_OS_WINDOWS_2008
```
    Is true if this is Windows Server 2008.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.1
  - IS_OS_WINDOWS_2012
```
public static final boolean IS_OS_WINDOWS_2012
```
    Is true if this is Windows Server 2012.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.4
  - IS_OS_WINDOWS_95
```
public static final boolean IS_OS_WINDOWS_95
```
    Is true if this is Windows 95.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_WINDOWS_98
```
public static final boolean IS_OS_WINDOWS_98
```
    Is true if this is Windows 98.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_WINDOWS_ME
```
public static final boolean IS_OS_WINDOWS_ME
```
    Is true if this is Windows ME.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_WINDOWS_NT
```
public static final boolean IS_OS_WINDOWS_NT
```
    Is true if this is Windows NT.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_WINDOWS_XP
```
public static final boolean IS_OS_WINDOWS_XP
```
    Is true if this is Windows XP.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.0
  - IS_OS_WINDOWS_VISTA
```
public static final boolean IS_OS_WINDOWS_VISTA
```
    Is true if this is Windows Vista.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    2.4
  - IS_OS_WINDOWS_7
```
public static final boolean IS_OS_WINDOWS_7
```
    Is true if this is Windows 7.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.0
  - IS_OS_WINDOWS_8
```
public static final boolean IS_OS_WINDOWS_8
```
    Is true if this is Windows 8.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.2
  - IS_OS_WINDOWS_10
```
public static final boolean IS_OS_WINDOWS_10
```
    Is true if this is Windows 10.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.5
  - IS_OS_ZOS
```
public static final boolean IS_OS_ZOS
```
    Is true if this is z/OS.
    
    The field will return false if OS_NAME is null.
    
    Since:
    
    3.5
- Constructor Detail
  - SystemUtils
```
public SystemUtils()
```
    SystemUtils instances should NOT be constructed in standard programming. Instead, the class should be used as SystemUtils.FILE_SEPARATOR.
    
    This constructor is public to permit tools that require a JavaBean instance to operate.
- Method Detail
  - getEnvironmentVariable
```
public static java.lang.String getEnvironmentVariable(java.lang.String name,
                                                      java.lang.String defaultValue)
```
    Gets an environment variable, defaulting to defaultValue if the variable cannot be read.
    
    If a SecurityException is caught, the return value is defaultValue and a message is written to System.err.
    
    Parameters:
    
    name - the environment variable name
    
    defaultValue - the default value
    
    Returns:
    
    the environment variable value or defaultValue if a security problem occurs
    
    Since:
    
    3.8
  - getHostName
```
public static java.lang.String getHostName()
```
    Gets the host name from an environment variable (COMPUTERNAME on Windows, HOSTNAME elsewhere).
    If you want to know what the network stack says is the host name, you should use InetAddress.getLocalHost().getHostName().
    
    Returns:
    
    the host name. Will be null if the environment variable is not defined.
    
    Since:
    
    3.6
  - getJavaHome
```
public static java.io.File getJavaHome()
```
    Gets the Java home directory as a File.
    
    Returns:
    
    a directory
    
    Throws:
    
    java.lang.SecurityException - if a security manager exists and its checkPropertyAccess method doesn't allow access to the specified system property.
    
    Since:
    
    2.1
    
    See Also:
    
    System.getProperty(String)
  - getJavaIoTmpDir
```
public static java.io.File getJavaIoTmpDir()
```
    Gets the Java IO temporary directory as a File.
    
    Returns:
    
    a directory
    
    Throws:
    
    java.lang.SecurityException - if a security manager exists and its checkPropertyAccess method doesn't allow access to the specified system property.
    
    Since:
    
    2.1
    
    See Also:
    
    System.getProperty(String)
  - getUserDir
```
public static java.io.File getUserDir()
```
    Gets the user directory as a File.
    
    Returns:
    
    a directory
    
    Throws:
    
    java.lang.SecurityException - if a security manager exists and its checkPropertyAccess method doesn't allow access to the specified system property.
    
    Since:
    
    2.1
    
    See Also:
    
    System.getProperty(String)
  - getUserHome
```
public static java.io.File getUserHome()
```
    Gets the user home directory as a File.
    
    Returns:
    
    a directory
    
    Throws:
    
    java.lang.SecurityException - if a security manager exists and its checkPropertyAccess method doesn't allow access to the specified system property.
    
    Since:
    
    2.1
    
    See Also:
    
    System.getProperty(String)
  - getUserName
```
public static java.lang.String getUserName()
```
    Gets the user name.
    
    Returns:
    
    a name
    
    Throws:
    
    java.lang.SecurityException - if a security manager exists and its checkPropertyAccess method doesn't allow access to the specified system property.
    
    Since:
    
    3.10
    
    See Also:
    
    System.getProperty(String)
  - getUserName
```
public static java.lang.String getUserName(java.lang.String defaultValue)
```
    Gets the user name.
    
    Parameters:
    
    defaultValue - A default value.
    
    Returns:
    
    a name
    
    Throws:
    
    java.lang.SecurityException - if a security manager exists and its checkPropertyAccess method doesn't allow access to the specified system property.
    
    Since:
    
    3.10
    
    See Also:
    
    System.getProperty(String)
  - isJavaAwtHeadless
```
public static boolean isJavaAwtHeadless()
```
    Returns whether the JAVA_AWT_HEADLESS value is true.
    
    Returns:
    
    true if JAVA_AWT_HEADLESS is "true", false otherwise.
    
    Since:
    
    2.1, Java 1.4
    
    See Also:
    
    JAVA_AWT_HEADLESS
  - isJavaVersionAtLeast
```
public static boolean isJavaVersionAtLeast(JavaVersion requiredVersion)
```
    Is the Java version at least the requested version.
    
    Parameters:
    
    requiredVersion - the required version, for example 1.31f
    
    Returns:
    
    true if the actual version is equal or greater than the required version
  - isJavaVersionAtMost
```
public static boolean isJavaVersionAtMost(JavaVersion requiredVersion)
```
    Is the Java version at most the requested version.
    
    Example input:
    
    Parameters:
    
    requiredVersion - the required version, for example 1.31f
    
    Returns:
    
    true if the actual version is equal or less than the required version
    
    Since:
    
    3.9

Class SystemUtils

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

AWT_TOOLKIT

FILE_ENCODING

FILE_SEPARATOR

JAVA_AWT_FONTS

JAVA_AWT_GRAPHICSENV

JAVA_AWT_HEADLESS

JAVA_AWT_PRINTERJOB

JAVA_CLASS_PATH

JAVA_CLASS_VERSION

JAVA_COMPILER

JAVA_ENDORSED_DIRS

JAVA_EXT_DIRS

JAVA_HOME

JAVA_IO_TMPDIR

JAVA_LIBRARY_PATH

JAVA_RUNTIME_NAME

JAVA_RUNTIME_VERSION

JAVA_SPECIFICATION_NAME

JAVA_SPECIFICATION_VENDOR

JAVA_SPECIFICATION_VERSION

JAVA_UTIL_PREFS_PREFERENCES_FACTORY

JAVA_VENDOR

JAVA_VENDOR_URL

JAVA_VERSION

JAVA_VM_INFO

JAVA_VM_NAME

JAVA_VM_SPECIFICATION_NAME

JAVA_VM_SPECIFICATION_VENDOR

JAVA_VM_SPECIFICATION_VERSION

JAVA_VM_VENDOR

JAVA_VM_VERSION

LINE_SEPARATOR

OS_ARCH

OS_NAME

OS_VERSION

PATH_SEPARATOR

USER_COUNTRY

USER_DIR

USER_HOME

USER_LANGUAGE

USER_NAME

USER_TIMEZONE

IS_JAVA_1_1

IS_JAVA_1_2

IS_JAVA_1_3

IS_JAVA_1_4

IS_JAVA_1_5

IS_JAVA_1_6

IS_JAVA_1_7

IS_JAVA_1_8

IS_JAVA_1_9

IS_JAVA_9

IS_JAVA_10

IS_JAVA_11

IS_JAVA_12

IS_JAVA_13

IS_JAVA_14

IS_JAVA_15

IS_OS_AIX

IS_OS_HP_UX

IS_OS_400

IS_OS_IRIX

IS_OS_LINUX

IS_OS_MAC

IS_OS_MAC_OSX

IS_OS_MAC_OSX_CHEETAH

IS_OS_MAC_OSX_PUMA

IS_OS_MAC_OSX_JAGUAR

IS_OS_MAC_OSX_PANTHER

IS_OS_MAC_OSX_TIGER

IS_OS_MAC_OSX_LEOPARD

IS_OS_MAC_OSX_SNOW_LEOPARD

IS_OS_MAC_OSX_LION

IS_OS_MAC_OSX_MOUNTAIN_LION