Системният клас на Java съдържа няколко полезни полета и методи на класа. Той също така предоставя съоръжения като стандартен вход, стандартен изход и изходни потоци за грешки. Не може да се инстанцира.

Класът Java System идва в модула на „java.base“ и в пакета на „java.lang“.

В Java System Class имаме 3 различни типа поле и 28 различни типа метод.

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Java System Class се състои от следните полета: -

Методи на системния клас на Java:

Java System Class се състои от следните методи: -

Пример 1

 import java.lang.*; public class SystemArrayCopyExample1 { public static void main(String[] args) { String a[]= {&apos;A&apos;,&apos;B&apos;,&apos;B&apos;,&apos;H&apos;,&apos;A&apos;,&apos;M&apos;}; //source array String b[]= {&apos;S&apos;,&apos;H&apos;,&apos;U&apos;,&apos;N&apos;,&apos;U&apos;,&apos;L&apos;,&apos;L&apos;,&apos;J&apos;,&apos;A&apos;,&apos;D&apos;,&apos;O&apos;,&apos;N&apos;}; //destination array String src[],dest[]; int srcPos,destPos,length; src=a; srcPos=2; dest=b; destPos=3; length=4; System.out.print(&apos;Source array:&apos;); for(int i=0;i<src.length;i++) {system.out.print(a[i]);} system.out.println(); system.out.print('destination array:'); for(int i="0;i&lt;src.length;i++)" {system.out.print(b[i]);} system.out.println('source position:'+srcpos); system.out.println('destination position:'+destpos); system.out.println('length:'+length); system.arraycopy(src, srcpos, dest, destpos, length); use of arraycopy() method array after arraycopy()'); <b.length;i++) { system.out.print(b[i]); } < pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> Source array:ABBHAM Destination array:SHUNUL Source Position:2 Destination Position:3 Length:4 Destination array after use of arraycopy() SHUBHAMJADON </pre> <h2>Example 2</h2> <pre> public class SystemCurrentTimeMillisExample2 { public static void main(String[] args) { System.out.println(&apos;Current time in millisecond&apos;); System.out.println(System.currentTimeMillis()); //method of calling current time in millisecond } } </pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> Current time in millisecond 1532262046724 </pre> <h2>Example 3</h2> <pre> public class SystemLineSeparatorExample3 { public static void main(String[] args) { //use of line separator String a=&apos;Shubham&apos;+System.lineSeparator()+&apos;Jadon&apos;; System.out.println(a); } } </pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> Shubham Jadon </pre> <h2>Example 4</h2> <pre> public class SystemNanoTimeExample4 { public static void main(String[] args) { System.out.println(&apos;Current time in nanoseconds = &apos;+System.nanoTime()); } } </pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> Current time in nanoseconds = 1316893720017448 </pre> <h2>Example 5</h2> <pre> public class SystemIdentityHashCodeExample5{ public static void main(String[] args) { String a=new String (); a.equals(&apos;Shubham&apos;); System.out.println(&apos;identity hash code of object a = &apos;+System.identityHashCode(a)); String b=new String (); b.equals(&apos;Jadon&apos;); System.out.println(&apos;identity hash code of object b = &apos;+System.identityHashCode(b)); } } </pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> identity hash code of object a = 843730481 identity hash code of object b = 743673026 </pre> <h2>Example 6</h2> <pre> import java.util.Properties; public class SystemGetPropertiesExample6 { public static void main(String[] args) { System.out.println(&apos;Your System property for user&apos;); Properties p = System.getProperties(); System.out.println(p.getProperty(&apos;user.name&apos;)); //property to get User&apos;s account name System.out.println(p.getProperty(&apos;user.home&apos;)); //property to get User&apos;s home directory System.out.println(p.getProperty(&apos;user.dir&apos;)); //property to get User&apos;s current working directory } } </pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> Your System property for user shubham C:UsersShubham Jadon C:UsersShubham Jadoneclipse-workspace	point </pre> <h2>Example 7</h2> <pre> import java.util.Properties; public class SystemGetPropertyExample7{ public static void main(String[] args) { //here we created property with my name and assigned its default value ShubhamJadon System.out.println(&apos;my name : &apos;+System.getProperty(&apos;myname&apos;, &apos;Shubham Jadon&apos;)); } } </pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> my name : Shubham Jadon </pre> <h2>Example 8</h2> <pre> public class SystemMpaLibraryNameExample8 { public static void main(String[] args) { System.out.println(&apos;map library for OS&apos;s name = &apos;+System.mapLibraryName(&apos;os.name&apos;)); System.out.println(&apos;map library for OS&apos;s architecture = &apos;+System.mapLibraryName(&apos;os.arch&apos;)); System.out.println(&apos;map library for OS&apos;s version = &apos;+System.mapLibraryName(&apos;os.version&apos;)); } } </pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> map library for OS&apos;s name = os.name.dll map library for OS&apos;s architecture = os.arch.dll map library for OS&apos;s version = os.version.dll </pre> <br></src.length;i++)>

Пример 2

 public class SystemCurrentTimeMillisExample2 { public static void main(String[] args) { System.out.println('Current time in millisecond'); System.out.println(System.currentTimeMillis()); //method of calling current time in millisecond } } 

Изход:

 Current time in millisecond 1532262046724 

Пример 3

 public class SystemLineSeparatorExample3 { public static void main(String[] args) { //use of line separator String a='Shubham'+System.lineSeparator()+'Jadon'; System.out.println(a); } } 

Изход:

 Shubham Jadon 

Пример 4

 public class SystemNanoTimeExample4 { public static void main(String[] args) { System.out.println('Current time in nanoseconds = '+System.nanoTime()); } } 

Изход:

 Current time in nanoseconds = 1316893720017448 

Пример 5

 public class SystemIdentityHashCodeExample5{ public static void main(String[] args) { String a=new String (); a.equals('Shubham'); System.out.println('identity hash code of object a = '+System.identityHashCode(a)); String b=new String (); b.equals('Jadon'); System.out.println('identity hash code of object b = '+System.identityHashCode(b)); } } 

Изход:

 identity hash code of object a = 843730481 identity hash code of object b = 743673026 

Пример 6

 import java.util.Properties; public class SystemGetPropertiesExample6 { public static void main(String[] args) { System.out.println('Your System property for user'); Properties p = System.getProperties(); System.out.println(p.getProperty('user.name')); //property to get User's account name System.out.println(p.getProperty('user.home')); //property to get User's home directory System.out.println(p.getProperty('user.dir')); //property to get User's current working directory } } 

Изход:

 Your System property for user shubham C:UsersShubham Jadon C:UsersShubham Jadoneclipse-workspace	point 

Пример 7

 import java.util.Properties; public class SystemGetPropertyExample7{ public static void main(String[] args) { //here we created property with my name and assigned its default value ShubhamJadon System.out.println('my name : '+System.getProperty('myname', 'Shubham Jadon')); } } 

Изход:

 my name : Shubham Jadon 

Пример 8

 public class SystemMpaLibraryNameExample8 { public static void main(String[] args) { System.out.println('map library for OS's name = '+System.mapLibraryName('os.name')); System.out.println('map library for OS's architecture = '+System.mapLibraryName('os.arch')); System.out.println('map library for OS's version = '+System.mapLibraryName('os.version')); } } 

Изход:

 map library for OS's name = os.name.dll map library for OS's architecture = os.arch.dll map library for OS's version = os.version.dll