/*** The <code>System</code> class contains several useful class fields* and methods. It cannot be instantiated.** <p>Among the facilities provided by the <code>System</code> class* are standard input, standard output, and error output streams;* access to externally defined properties and environment* variables; a means of loading files and libraries; and a utility* method for quickly copying a portion of an array.** @author  unascribed* @since   JDK1.0*/
public final class System {/* register the natives via the static initializer.** VM will invoke the initializeSystemClass method to complete* the initialization for this class separated from clinit.* Note that to use properties set by the VM, see the constraints* described in the initializeSystemClass method.*/private static native void registerNatives();static {registerNatives();}/** Don't let anyone instantiate this class */private System() {}

public static void exit(int status) {Runtime.getRuntime().exit(status);}

package com.ysdx.test;public class JavaTest {public static void main(String[] args) {Thread thread = new Thread(() -> {try {Thread.sleep(1000);} catch (InterruptedException e) {// TODO Auto-generated catch block
                e.printStackTrace();}System.out.println("hello!");System.exit(1);});thread.start();try {Thread.sleep(3000);} catch (InterruptedException e) {// TODO Auto-generated catch block
            e.printStackTrace();}System.out.println("Hello from main thread!");}
}

public class JavaTest1 {public static void main(String[] args) {try {Thread.sleep(3000);} catch (InterruptedException e) {// TODO Auto-generated catch block
            e.printStackTrace();}System.out.println("Hello from main thread!");}
}

/*** Runs the garbage collector.* <p>* Calling the <code>gc</code> 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 Java Virtual* Machine has made a best effort to reclaim space from all discarded* objects.* <p>* The call <code>System.gc()</code> is effectively equivalent to the* call:* <blockquote><pre>* Runtime.getRuntime().gc()* </pre></blockquote>** @see     java.lang.Runtime#gc()*/public static void gc() {Runtime.getRuntime().gc();}/*** Runs the finalization methods of any objects pending finalization.* <p>* Calling this method suggests that the Java Virtual Machine expend* effort toward running the <code>finalize</code> methods of objects* that have been found to be discarded but whose <code>finalize</code>* methods have not yet been run. When control returns from the* method call, the Java Virtual Machine has made a best effort to* complete all outstanding finalizations.* <p>* The call <code>System.runFinalization()</code> is effectively* equivalent to the call:* <blockquote><pre>* Runtime.getRuntime().runFinalization()* </pre></blockquote>** @see     java.lang.Runtime#runFinalization()*/public static void runFinalization() {Runtime.getRuntime().runFinalization();}

/*** 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.* <p>* The name <code>gc</code> stands for "garbage* collector". The virtual machine performs this recycling* process automatically as needed, in a separate thread, even if the* <code>gc</code> method is not invoked explicitly.* <p>* 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</code> methods of objects* that have been found to be discarded but whose <code>finalize</code>* 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.* <p>* The virtual machine performs the finalization process* automatically as needed, in a separate thread, if the* <code>runFinalization</code> method is not invoked explicitly.* <p>* The method {@link System#runFinalization()} is the conventional* and convenient means of invoking this method.** @see     java.lang.Object#finalize()*/public void runFinalization() {runFinalization0();}

 public static String getenv(String name) {SecurityManager sm = getSecurityManager();if (sm != null) {sm.checkPermission(new RuntimePermission("getenv."+name));}return ProcessEnvironment.getenv(name);}public static java.util.Map<String,String> getenv() {SecurityManager sm = getSecurityManager();if (sm != null) {sm.checkPermission(new RuntimePermission("getenv.*"));}return ProcessEnvironment.getenv();}

java.runtime.name = Java(TM) SE Runtime Environment
sun.boot.library.path = C:\Program Files\Java\jre1.8.0_121\bin
java.vm.version = 25.121-b13
java.vm.vendor = Oracle Corporation
java.vendor.url = http://java.oracle.com/
path.separator = ;
java.vm.name = Java HotSpot(TM) 64-Bit Server VM
file.encoding.pkg = sun.io
user.script =
user.country = CN
sun.java.launcher = SUN_STANDARD
sun.os.patch.level =
java.vm.specification.name = Java Virtual Machine Specification
user.dir = F:\CodingSource\neon-workspace\JavaSystem
java.runtime.version = 1.8.0_121-b13
java.awt.graphicsenv = sun.awt.Win32GraphicsEnvironment
java.endorsed.dirs = C:\Program Files\Java\jre1.8.0_121\lib\endorsed
os.arch = amd64
java.io.tmpdir = C:\Users\ADMINI~1\AppData\Local\Temp\
line.separator = java.vm.specification.vendor = Oracle Corporation
user.variant =
os.name = Windows 8
sun.jnu.encoding = GBK
java.library.path = C:\Program Files\Java\jre1.8.0_121\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:/Program Files/Java/jre1.8.0_121/bin/server;C:/Program Files/Java/jre1.8.0_121/bin;C:/Program Files/Java/jre1.8.0_121/lib/amd64;E:\CodingIDE\Python36\Scripts\;E:\CodingIDE\Python36\;E:\CodingIDE\DataBase\oraclexe\app\oracle\product\11.2.0\server\bin;;C:\ProgramData\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files\Java\jdk1.8.0_121\bin;C:\Program Files\Java\jdk1.8.0_121\jre\bin;E:\CodingIDE\DataBase\mysql-5.7.17-winx64\bin;E:\CodingIDE\eclipse-jee-neon-3-RC3-win32-x86_64\eclipse;;.
java.specification.name = Java Platform API Specification
java.class.version = 52.0
sun.management.compiler = HotSpot 64-Bit Tiered Compilers
os.version = 6.2
user.home = C:\Users\Administrator
user.timezone =
java.awt.printerjob = sun.awt.windows.WPrinterJob
file.encoding = GBK
java.specification.version = 1.8
user.name = Administrator
java.class.path = F:\CodingSource\neon-workspace\JavaSystem\bin
java.vm.specification.version = 1.8
sun.arch.data.model = 64
java.home = C:\Program Files\Java\jre1.8.0_121
sun.java.command = com.ysdx.jsys.JavaSystem
java.specification.vendor = Oracle Corporation
user.language = zh
awt.toolkit = sun.awt.windows.WToolkit
java.vm.info = mixed mode
java.version = 1.8.0_121
java.ext.dirs = C:\Program Files\Java\jre1.8.0_121\lib\ext;C:\Windows\Sun\Java\lib\ext
sun.boot.class.path = C:\Program Files\Java\jre1.8.0_121\lib\resources.jar;C:\Program Files\Java\jre1.8.0_121\lib\rt.jar;C:\Program Files\Java\jre1.8.0_121\lib\sunrsasign.jar;C:\Program Files\Java\jre1.8.0_121\lib\jsse.jar;C:\Program Files\Java\jre1.8.0_121\lib\jce.jar;C:\Program Files\Java\jre1.8.0_121\lib\charsets.jar;C:\Program Files\Java\jre1.8.0_121\lib\jfr.jar;C:\Program Files\Java\jre1.8.0_121\classes
java.vendor = Oracle Corporation
file.separator = \
java.vendor.url.bug = http://bugreport.sun.com/bugreport/
sun.cpu.endian = little
sun.io.unicode.encoding = UnicodeLittle
sun.desktop = windows
sun.cpu.isalist = amd64
-----------------------------------
USERDOMAIN_ROAMINGPROFILE=PC-201703120850
LOCALAPPDATA=C:\Users\Administrator\AppData\Local
PROCESSOR_LEVEL=6
FP_NO_HOST_CHECK=NO
USERDOMAIN=PC-201703120850
LOGONSERVER=\\PC-201703120850
JAVA_HOME=C:\Program Files\Java\jdk1.8.0_121
SESSIONNAME=Console
ALLUSERSPROFILE=C:\ProgramData
PROCESSOR_ARCHITECTURE=AMD64
PSModulePath=C:\Windows\system32\WindowsPowerShell\v1.0\Modules\
#envTSLOGSHELLEXT3464=510784384
SystemDrive=C:
=C:=C:\
APPDATA=C:\Users\Administrator\AppData\Roaming
USERNAME=Administrator
ProgramFiles(x86)=C:\Program Files (x86)
VBOX_MSI_INSTALL_PATH=F:\VirtualBox\
CommonProgramFiles=C:\Program Files\Common Files
Path=C:/Program Files/Java/jre1.8.0_121/bin/server;C:/Program Files/Java/jre1.8.0_121/bin;C:/Program Files/Java/jre1.8.0_121/lib/amd64;E:\CodingIDE\Python36\Scripts\;E:\CodingIDE\Python36\;E:\CodingIDE\DataBase\oraclexe\app\oracle\product\11.2.0\server\bin;;C:\ProgramData\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files\Java\jdk1.8.0_121\bin;C:\Program Files\Java\jdk1.8.0_121\jre\bin;E:\CodingIDE\DataBase\mysql-5.7.17-winx64\bin;E:\CodingIDE\eclipse-jee-neon-3-RC3-win32-x86_64\eclipse;
PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC;.PY;.PYW
OS=Windows_NT
COMPUTERNAME=PC-201703120850
PROCESSOR_REVISION=3a09
CommonProgramW6432=C:\Program Files\Common Files
#envTSLOGsss3464=166647136
ComSpec=C:\Windows\system32\cmd.exe
#envTSLOGXMediaLibrary3464=166645216
ProgramData=C:\ProgramData
=F:=F:\
ProgramW6432=C:\Program Files
HOMEPATH=\Users\Administrator
SystemRoot=C:\Windows
TEMP=C:\Users\ADMINI~1\AppData\Local\Temp
HOMEDRIVE=C:
PROCESSOR_IDENTIFIER=Intel64 Family 6 Model 58 Stepping 9, GenuineIntel
USERPROFILE=C:\Users\Administrator
TMP=C:\Users\ADMINI~1\AppData\Local\Temp
CommonProgramFiles(x86)=C:\Program Files (x86)\Common Files
ProgramFiles=C:\Program Files
PUBLIC=C:\Users\Public
NUMBER_OF_PROCESSORS=4
windir=C:\Windows
#envTSLOGTSLOG3464=166646496
=::=::\

package com.ysdx.jsys;import java.util.Enumeration;
import java.util.Map;
import java.util.Properties;public class JavaSystem {public static void main(String[] args) {Properties properties = System.getProperties();Enumeration<?> propertyNames = properties.propertyNames();for (; propertyNames.hasMoreElements();) {String propertyName = (String) propertyNames.nextElement();System.out.println(propertyName + " = " + properties.getProperty(propertyName));}System.out.println("-----------------------------------");Map<String, String> map = System.getenv();for (String key : map.keySet()) {System.out.println(key + "=" + map.get(key));}}}