Increament operator error

i started learning JAVA a few days back.
i thought of writing my first program on arithmetic operators.
but i m getting compilation error with the "++" operator.
below is my code.

public class IntArithmeticOperations {
       public static void main(String args[]){
	 System.out.println("Arithmetic Operations Sample");
	 
	 int i=10;
	 
	 int increamentResult=++i;//This is ok
	 int increamentResult1=++(i);//This is also ok
	 int increamentResult2=doit(++i);  //This is also ok
	 int increamentResult3=++(++i);   //This gives a compilation
error
	 int increamentResult4=++(i=i++); //This gives a compilation error
	 int increamentResult5=++(i+1); //This gives a compilation error
	 
	 System.out.println("IncreamentResult is"+increamentResult);
	 System.out.println("IncreamentResult1 is"+increamentResult1);
	 System.out.println("IncreamentResult2 is"+increamentResult2);
	 System.out.println("IncreamentResult3 is"+increamentResult3);
	 System.out.println("IncreamentResult4 is"+increamentResult4);
	 System.out.println("IncreamentResult5 is"+increamentResult5);
    }
 public static int doit(int i){
	 return i;
 }
}

Please help me understand how the "++" operator works.