Get/set system property « System « Development

Return	Method	Summary
static String	clearProperty(String key)	Removes the system property.
static String	getenv(String name)	Gets the value of the specified environment variable.
static Properties	getProperties()	Determines the current system properties.
static String	getProperty(String key)	Gets the system property.
static String	getProperty(String key, String def)	Gets the system property.
static void	setProperties(Properties props)	Sets the system properties to the Properties argument.
static String	setProperty(String key, String value)	Sets the system property.


public class Main {

  public static void main(String args[]) {
    System.setProperty("myKey", "myValue");
    
    System.out.println(System.getProperty("myKey"));

  }
}


myValue

 

public class Main {
  public static void main(String[] args) {
    String strOSName = System.getProperty("os.name");
    if (strOSName != null) {
      if (strOSName.toLowerCase().indexOf("windows") != -1)
        System.out.println("Windows");
      else
        System.out.print("not windows");
    }
  }
}


Windows