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Page 271 of 589
Display the Operating System name in Java
Use the System.getProperty() method in Java to get the Operating System name.It’s syntax is −String getProperty(String key)Above, the key is the name of the system property. Since, we want the OS name, therefore we will add the key as −os.nameExamplepublic class Demo { public static void main(String[] args) { System.out.print("Operating System: "); System.out.println(System.getProperty("os.name")); } }OutputOperating System: Linux
Read MoreTokenizing a String in Java
We have the following string −String str = "This is demo text, and demo line!";To tokenize the string, let us split them after every period (.) and comma (,)String str = "This is demo text, and demo line!";The following is the complete example.Examplepublic class Demo { public static void main(String[] args) { String str = "This is demo text, and demo line!"; String[] res = str.split("[, .]", 0); for(String myStr: res) { System.out.println(myStr); } } }OutputThis is demo text and demo line!
Read MoreReturn all system properties in Java
To return all the system properties in Java, firstly use the System.getProperties() method.java.util.Properties prop = System.getProperties();After that, use the list() method to list all of them.prop.list(System.out);Examplepublic class MainClass { public static void main(String[] args) { java.util.Properties prop = System.getProperties(); prop.list(System.out); } }Outputjava.runtime.name=OpenJDK Runtime Environment sun.boot.library.path=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0... java.vm.version=25.141-b16 java.vm.vendor=Oracle Corporation java.vendor.url=http://java.oracle.com/ path.separator=: java.vm.name=OpenJDK 64-Bit Server VM file.encoding.pkg=sun.io user.country=US sun.java.launcher=SUN_STANDARD sun.os.patch.level=unknown java.vm.specification.name=Java Virtual Machine Specification user.dir=/home/cg/root/3757524 java.runtime.version=1.8.0_141-b16 java.awt.graphicsenv=sun.awt.X11GraphicsEnvironment java.endorsed.dirs=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0... os.arch=amd64 java.io.tmpdir=/tmp line.separator= java.vm.specification.vendor=Oracle Corporation os.name=Linux sun.jnu.encoding=UTF-8 java.library.path=/home/cg/root/GNUstep/Library/Librari... java.specification.name=Java Platform API Specification java.class.version=52.0 sun.management.compiler=HotSpot 64-Bit Tiered Compilers os.version=3.10.0-862.9.1.el7.x86_64 user.home=? user.timezone= java.awt.printerjob=sun.print.PSPrinterJob file.encoding=UTF-8 java.specification.version=1.8 user.name=? java.class.path=/home/cg/root/GNUstep/Library/Librari... java.vm.specification.version=1.8 sun.arch.data.model=64 java.home=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0... sun.java.command=MainClass java.specification.vendor=Oracle Corporation user.language=en awt.toolkit=sun.awt.X11.XToolkit ...
Read MoreCopy characters from string into char Array in Java
Let’s say we have the following string.String str = "Demo Text!";To copy some part of the above string, use the getChars() method.// copy characters from string into chArray =str.getChars( 0, 5, chArray, 0 );The following is an example to copy characters from string into char Array in Java.Examplepublic class Demo { public static void main(String[] args) { String str = "Demo Text!"; char chArray[] = new char[ 5 ]; System.out.println("String: "+str); // copy characters from string into chArray str.getChars( 0, 5, chArray, 0 ); ...
Read MoreGet the default system properties in Java
To return all the default systems properties in Java, firstly use the System.getProperties() method.java.util.Properties prop = System.getProperties();After that, use the list() method to list all of them.prop.list(System.out);Examplepublic class Demo { public static void main(String[] args) { java.util.Properties prop = System.getProperties(); System.out.println("Here are the Properties:"); prop.list(System.out); } }OutputHere are the Properties: java.runtime.name=OpenJDK Runtime Environment sun.boot.library.path=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0... java.vm.version=25.141-b16 java.vm.vendor=Oracle Corporation java.vendor.url=http://java.oracle.com/ path.separator=: java.vm.name=OpenJDK 64-Bit Server VM file.encoding.pkg=sun.io user.country=US sun.java.launcher=SUN_STANDARD sun.os.patch.level=unknown java.vm.specification.name=Java Virtual Machine Specification user.dir=/home/cg/root/3757524 java.runtime.version=1.8.0_141-b16 java.awt.graphicsenv=sun.awt.X11GraphicsEnvironment java.endorsed.dirs=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0... os.arch=amd64 java.io.tmpdir=/tmp line.separator= java.vm.specification.vendor=Oracle Corporation os.name=Linux sun.jnu.encoding=UTF-8 java.library.path=/home/cg/root/GNUstep/Library/Librari... java.specification.name=Java Platform API Specification java.class.version=52.0 sun.management.compiler=HotSpot 64-Bit Tiered Compilers os.version=3.10.0-862.9.1.el7.x86_64 user.home=? user.timezone= java.awt.printerjob=sun.print.PSPrinterJob file.encoding=UTF-8 ...
Read MoreDisplay ISO 8601 standard date in Java
Use the ‘F’ date conversion character to display ISO 8601 standard date.System.out.printf("ISO 8601 standard date = %tF", d);Above, d is a date object.Date d = new Date();Exampleimport java.util.Date; import java.text.DateFormat; import java.text.SimpleDateFormat; public class Demo { public static void main(String[] args) throws Exception { Date d = new Date(); System.out.printf("Four-digit Year = %TY",d); System.out.printf("Two-digit Year = %ty",d); System.out.printf("ISO 8601 standard date = %tF", d); } }OutputFour-digit Year = 2018 Two-digit Year = 18 ISO 8601 standard date = 2018-11-26
Read MoreNarrowing Conversion in Java
Narrowing conversion is needed when you convert from a larger size type to a smaller size. This is for incompatible data types, wherein automatic conversions cannot be done.Let us see an example wherein we are converting long to integer using Narrowing Conversion.Examplepublic class Demo { public static void main(String[] args) { long longVal = 878; int intVal = (int) longVal; System.out.println("Long: "+longVal); System.out.println("Integer: "+intVal); } }OutputLong: 878 Integer: 878Let us see another example, wherein we are converting double to long using Narrowing Conversion.Examplepublic class Demo { public static void main(String[] args) { double doubleVal = 299.89; long longVal = (long)doubleVal; System.out.println("Double: "+doubleVal); ...
Read MoreUnix date format in Java
Use the ‘c’ date conversion character to display UNIX date format in Java.System.out.printf("Unix date format: %tc",d);Above, d is a date object.Date d = new Date();Exampleimport java.util.Date; import java.text.DateFormat; import java.text.SimpleDateFormat; public class Demo { public static void main(String[] args) throws Exception { Date d = new Date(); System.out.printf("Unix date format: %tc",d); System.out.printf("Unix date format: %Tc",d); } }OutputUnix date format: Mon Nov 26 12:24:10 UTC 2018 Unix date format: MON NOV 26 12:24:10 UTC 2018
Read MoreConvert string of time to time object in Java
Here is our string.String strTime = "20:15:40";Now, use the DateFormat to set the format for date.DateFormat dateFormat = new SimpleDateFormat("hh:mm:ss");Parse the string of time to time object.Date d = dateFormat.parse(strTime);The following is the complete example.Exampleimport java.text.DateFormat; import java.util.Date; import java.text.SimpleDateFormat; public class Demo { public static void main(String[] args) throws Exception { String strTime = "20:15:40"; DateFormat dateFormat = new SimpleDateFormat("hh:mm:ss"); Date d = dateFormat.parse(strTime); System.out.println("Resultant Date and Time = " + d); } }OutputResultant Date and Time = Thu Jan 01 20:15:40 UTC 1970
Read MoreIntegral conversion characters in Java
Intergral conversion characters include the following.CharacterDescription%dInteger%oOctal%xHexadecimal%XHexadecimalExamplepublic class Demo { public static void main(String[] args) throws Exception { System.out.printf( "Integer: %d", 889 ); System.out.printf( "Negative Integer: %d", -78 ); System.out.printf( "Octal: %o", 677 ); System.out.printf( "Hexadecimal: %x", 56 ); System.out.printf( "Hexadecimal: %X", 99 ); } }OutputInteger: 889 Negative Integer: -78 Octal: 1245 Hexadecimal: 38 Hexadecimal: 63
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