The java operator taking one operand is called Increment and Decrement Operators(Unary Operator) .

The most basic two unary operators such as increment operator(++) and decrement operator(--).

Again increment operator is divided into two categories such as pre-increment and post-increment.

Similarly decrement operator is also devided into pre-decrement and post-decrement.

In case of pre-increment/ decrement first the value of variable will increment / decrement a value by 1, then it will display.

where as in case of post-increment / decrement, first the value of variable will display then it will increment / decrement.

Let's see some unary operators :

+ // Unary plus operator; indicates positive value (numbers are positive without this, however)
- //Unary minus operator; negates an expression
++ //Increment operator; increments a value by 1
-- //Decrement operator; decrements a value by 1
! //Logical complement operator; inverts the value of a Boolean

let's see some following small examples :

class Increment
{
  public static void main(String args[])
  {
	  int x=5,y;
	  y=x++ + x++ + ++x + x++ + ++x;
	  System.out.println("y="+y);
  }
}

Output
y=37

class TestUnary
{
  public static void main(String args[])
  {
	  int x=8,y;
	  y=++x + ++x - x++ + ++x - --x;
	  System.out.println("y="+y);
  }
}

Output
y=10