java.lang.System : System Class « Development « Java Tutorial






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The System class is a final class that exposes useful static fields. The static methods can help you with common tasks.

The out field represents the standard output stream which by default is the same console.

public class MainClass {

  public static void main(String[] args) {
    String message = "qwer";
    System.out.print(message);

  }

}








6.1.System Class
6.1.1.java.lang.System
6.1.2.PrintStream has many print method overloads that accept different types
6.1.3.println adds a line terminator at the end of the argument
6.1.4.The err field represents a PrintStream object
6.1.5.The 'in' field represents the standard input stream
6.1.6.Array copy method
6.1.7.Terminates the running program and the current JVM
6.1.8.Returns the computer time in milliseconds
6.1.9.public static long nanoTime(): provide more precision, i.e. in nanoseconds
6.1.10.Using System.getProperty(String key) to retrieve system properties
6.1.11.Get Name of User Currently Logged In to the Computer
6.1.12.Create a user-defined property or change the value of the current property
6.1.13.Returns a default value if the specified property does not exist
6.1.14.Returns all system properties
6.1.15.Exiting a Java program
6.1.16.Terminate virtual machine using System class
6.1.17.Redirect the output of System.out to a file.
6.1.18.Calculate process elapsed time