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تحتوي فئة النظام في Java على العديد من حقول وأساليب الفئة المفيدة. كما يوفر أيضًا تسهيلات مثل الإدخال القياسي والإخراج القياسي وتدفقات إخراج الأخطاء. لا يمكن إنشاء مثيل له.

تأتي فئة نظام Java في الوحدة النمطية 'java.base' وفي حزمة 'java.lang'.

في Java System Class، لدينا 3 أنواع مختلفة من الحقول و28 نوعًا مختلفًا من الأساليب.

تتكون Java System Class من الحقول التالية: -

أساليب فئة نظام جافا:

تتكون Java System Class من الطرق التالية: -

مثال 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++)>

مثال 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 } } 

انتاج:

 Current time in millisecond 1532262046724 

مثال 3

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

انتاج:

 Shubham Jadon 

مثال 4

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

انتاج:

 Current time in nanoseconds = 1316893720017448 

مثال 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)); } } 

انتاج:

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

مثال 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 } } 

انتاج:

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

مثال 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')); } } 

انتاج:

 my name : Shubham Jadon 

مثال 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')); } } 

انتاج:

 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