1 - Scope

• The following code will compile !

public class Test1 {

    int a=0;

    void method1(int a0) {

        int a1=0;

        { int a=0;}

        for(int a=0;a < 10; a++) {
            System.out.println("" + a);
        }

        for(int a=0;a < 10; a++) {
            System.out.println("" + a);
        }

    }

}
The declaration of the integer in the block of code surrounded by {} and in the 2 for will NOT interfere !

• But if you change the name of the method parameter "a0" to "a" OR the name of the local variable "a1" to "a" the method will not compile anymore ! The compiler will complain that "a" hides a field OR that "a" is already defined !
  

• Could you notice that in the case you didn't rename "a0" and "a1" that the "int a" in the code will hide the instance variable !