Basic errors in assignments

1. Local variables of a method are never initialised automatically. It would be a compile time error if we try to access them without initialisation.

2. int a;

   System.out.print(a);

  This is compile time error as a is not initialised.

3. int a=4, b;

    if(a==4)

        b=5;

   System.out.print(a);

   This is compile time error because variable expression a==4 will be checked at run time. So b will be uninitialised at compile time.

4.  int a=4, b;

     if(a==4)
        b=5;
    System.out.print(a);

    This is right as due to final a==4 is a constant expression and will be checked at compile time.

5. String str = "25";

    int no;

    no = str;   //Compile Time error

 This will be a compile time error. To remove error we should use

    no= Integer.parseInt(str);

 parse is a static method in Integer class which returns the integer conversion of the string.