if (booleanExpression ) { System.out.println("Inside a IF statement ");
        
if ( age == 65 ) { System.out.println("Book yourself a retirement holiday");
        
if (true)
    System.out.println("Hello ");       
    System.out.print("World!");                 // you actually don't need brackets but it can be hard to read code, this is not part of the if statement
        
if (false);                        
    System.out.println("Hello World!");         // notice the semi-colon at the end of the if statement, this terminates the if statement imediately and this line always executes
        
Note: you can nest if and if-else statements

if ( price < 100 ) {
   System.out.println("Buy it, it's a bargain");
}
else {
   System.out.println("It's to pricey wait until the sales");
}

// You can also remove the brackets when you only have one line of code for each true or false
if ( price < 100 )
   System.out.println("Buy it, it's a bargain");
else
   System.out.println("It's to pricey wait until the sales");

// Using a if-else-if
if ( price < 100 )
   System.out.println("Buy it, it's a bargin"):
else if ( price < 110 )
   System.out.println("You might be tempted");
else
   System.out.println("It's to pricey wait until the sales");

Note: always indent conditional code it makes it much more pleasant on the eyes

result = ( a < b ; a ? b);

if the condition a < b is true then the value of a is assigned to result
if the condition a < b is false then the value of b is assigned to result

Note: The ternary operator (conditional operator) is a short-hand of a if-else statement

int x = 3;

switch (x) {
  case 1:
    System.out.println("x is equal to one");
    break;
  case 2:
    System.out.println("x is equal to two");
    break;
  case (1 + 2):                                   // can even use expressions as well
    System.out.println("x is equal to three");
    break;
  default:                                        // default block does not need to be at the end or even included
    System.out.println("No idea what x is ?????");
}

Note: switch statements can only evaluate byte (Byte), short (Short), int (Integer) and char (Character), enumerated types and the String class

Note: missing break statements means that all case statements will be executed, known as fall-through 

Note: you can nest switch statements, when the compiler compiles a switch statement it will inspect each case statement and create a "jump" table that it will use for 
      selecting the path of execution depending on the value of the expression. This gives it an advantage (better performance) over large if-else statement.

int x = 0;
while ( x < 10 ) {
    System.out.println("x is still less than 10");
    x++;
}

i = 100;
j = 200;
while(++i < --j);           // no body but will find the midpoint between i and j

System.out.println("Midpoint is " + i);

Note: it is possible that the while body may never be executed 

int x = 0;

do {
  System.out.println("x is still less than 10");
  x++;
} while ( x < 10 );            // notice the semi-colon 

Note: The while body will always be executed once, also notice the semi-colon at the end of the while expression 

for ( int x = 0; x < 10; x++) {
    System.out.println("x is still less than 10");
}

# More complex FOR loop
for ( int x = 0, y = 0; ( (x < 10) && (y < 10) ); x++, y++) {
    System.out.println("x and y are still less than 10");
}

Note: you can have only one logical expression but it can be very complex.

The for statement is made up of three parts

• Control variable initialization (only called once)
• Loop continuation Condition (must evaluate to true or false)
• Increment/Decrement of the control variable (executed after the iteration)

   for ( control variable initialization ; loop continuation ; increment/decrement of the control variable )

More information about loops:

• You cannot reference a label with the continue or break statements that are not in the loop scope, a compile error occurs
• An outer loop cannot reference the inners loop's labels, but an inner loop can reference the outer's loop lables
• You can break out of a nested loop from a nested loop
• You can also completely break out of a parent loop

init i = 0; 
for(Strings arg : args) {
  System.out.println("Argument " + (++i) + " = " + arg);
}

int nums[] = { 1, 2, 3, 4, 5};
for(int i : nums) {
    if (i == 3)               
        continue;

    System.out.println(i);
}

Note: you can also use the break, continue and return

int counter = 1;

while (counter <= 10 ) {
   System.out.println ( "Counter = " + counter + " We will break on 5" );
   if ( counter == 5 )
      // Break out of the while loop
      break;
   counter++;
}

Note: The break statement when executed in a while, do/while or switch statement causes immediate exit from that structure and continues on to the next statement after the while, do/while or switch structure.

int counter = 1;

while (counter <= 10 ) {
   if ( (counter % 2) == 0 ) {
      System.out.println ( "Counter = " + counter + " Do not print odd numbers" );
      counter++;
      continue;
   }
   counter++;
}

Note:The continue statement when executed in a while, do/while or switch skips the remaining body statements and proceeds to the next iteration of the loop.

int nums[] = { 1, 2, 3, 4, 5};

for(int i : nums) {
    if (i == 3)
        return;                     // once i equals 3 the for loop will be terminated

    System.out.println(i);
}

stop: // labelled compound statement
   for ( int row = 1; row <= 10; row++ ) {
      for ( int column = 1; column <= 5; column++ ) {
         if ( row == 5 )
            break stop;   // Jump to end of stop block
      }
   }

Note: Labelled break/continue statements are to breakout of nested set of structures, the beginning of the nested structure starts with a label which is a place that the break statement will exit from.