//int(type) followed ... (three dot's) is syntax of a variable argument. 
 public int sum(int... numbers) {
 //inside the method a variable argument is similar to an array.
 //number can be treated as if it is declared as int[] numbers;
 int sum = 0;
 for (int number: numbers) {
  sum += number;
 }
 return sum;
 }
 public static void main(String[] args) {
 VariableArgumentExamples example = new VariableArgumentExamples();
 //3 Arguments
 System.out.println(example.sum(1, 4, 5));//10
 //4 Arguments
 System.out.println(example.sum(1, 4, 5, 20));//30
 //0 Arguments
 System.out.println(example.sum());//0
 }

private int computerSimpleInterest(int principal,float interest,int years){
 assert(principal>0);
 return 100;
}

void method(){
 Calendar calendar = new GregorianCalendar(2000,10,30);
 System.out.println(calendar);
}

public class InitializerExamples {
 static int count;
 int i;
 static{
 //This is a static initializers. Run only when Class is first loaded.
 //Only static variables can be accessed
 System.out.println("Static Initializer");
 //i = 6;//COMPILER ERROR
 System.out.println("Count when Static Initializer is run is " + count);
 }
 public static void main(String[] args) {
 InitializerExamples example = new InitializerExamples();
 InitializerExamples example2 = new InitializerExamples();
 InitializerExamples example3 = new InitializerExamples();
 }
}

Static Initializer
Count when Static Initializer is run is 0.

public class InitializerExamples {
 static int count;
 int i;
 {
 //This is an instance initializers. Run every time an object is created.
 //static and instance variables can be accessed
 System.out.println("Instance Initializer");
 i = 6;
 count = count + 1;
 System.out.println("Count when Instance Initializer is run is " + count);
 }
 public static void main(String[] args) {
 InitializerExamples example = new InitializerExamples();
 InitializerExamples example1 = new InitializerExamples();
 InitializerExamples example2 = new InitializerExamples();
 }
}

Instance Initializer
 Count when Instance Initializer is run is 1
 Instance Initializer
 Count when Instance Initializer is run is 2
 Instance Initializer
 Count when Instance Initializer is run is 3

private static void tokenize(String string,String regex) {
 String[] tokens = string.split(regex);
 System.out.println(Arrays.toString(tokens));
}
tokenize("ac;bd;def;e",";");//[ac, bd, def, e]

private static void tokenizeUsingScanner(String string,String regex) {
 Scanner scanner = new Scanner(string);
 scanner.useDelimiter(regex);
 List<String> matches = new ArrayList<String>();
 while(scanner.hasNext()){
 matches.add(scanner.next());
 }
 System.out.println(matches);
}
tokenizeUsingScanner("ac;bd;def;e",";");//[ac, bd, def, e]

Date date = new Date();
//Increase time by 6 hrs
date.setTime(date.getTime() + 6 * 60 * 60 * 1000);
System.out.println(date);
//Decrease time by 6 hrs
date = new Date();
date.setTime(date.getTime() - 6 * 60 * 60 * 1000);
System.out.println(date);

//Formatting Dates
System.out.println(DateFormat.getInstance().format(
 date));//10/16/12 5:18 AM

System.out.println(DateFormat.getDateInstance(
 DateFormat.FULL, new Locale("it", "IT"))
 .format(date));//marted“ 16 ottobre 2012
System.out.println(DateFormat.getDateInstance(
 DateFormat.FULL, Locale.ITALIAN)
 .format(date));//marted“ 16 ottobre 2012
//This uses default locale US
System.out.println(DateFormat.getDateInstance(
 DateFormat.FULL).format(date));//Tuesday, October 16, 2012
System.out.println(DateFormat.getDateInstance()
 .format(date));//Oct 16, 2012
System.out.println(DateFormat.getDateInstance(
 DateFormat.SHORT).format(date));//10/16/12
System.out.println(DateFormat.getDateInstance(
 DateFormat.MEDIUM).format(date));//Oct 16, 2012
System.out.println(DateFormat.getDateInstance(
 DateFormat.LONG).format(date));//October 16, 2012

//Calendar calendar = new Calendar(); //COMPILER ERROR
Calendar calendar = Calendar.getInstance();

calendar.set(Calendar.DATE, 24);
calendar.set(Calendar.MONTH, 8);//8 - September
calendar.set(Calendar.YEAR, 2010);

System.out.println(calendar.get(Calendar.YEAR));//2010
System.out.println(calendar.get(Calendar.MONTH));//8
System.out.println(calendar.get(Calendar.DATE));//24
System.out.println(calendar.get(Calendar.WEEK_OF_MONTH));//4
System.out.println(calendar.get(Calendar.WEEK_OF_YEAR));//39
System.out.println(calendar.get(Calendar.DAY_OF_YEAR));//267
System.out.println(calendar.getFirstDayOfWeek());//1 -> Calendar.SUNDAY

System.out.println(NumberFormat.getInstance().format(321.24f));//321.24

System.out.println(NumberFormat.getInstance(new Locale("nl")).format(4032.3f));//4.032,3

System.out.println(NumberFormat.getInstance(Locale.GERMANY).format(4032.3f));//4.032,3

System.out.println(NumberFormat.getCurrencyInstance().format(40324.31f));//$40,324.31

System.out.println(NumberFormat.getCurrencyInstance(new Locale("nl")).format(40324.31f));//? 40.324,31