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Little 4Qs

lashkar
Greenhorn

Joined: Jul 14, 2001
Posts: 18
Q1. A method cant be overRidden to be more Private ?
if so ,
class cls {
void aMethod (){}
}
class clsChld extends cls {
X void aMethod(){}
}
// the X can Olny be Private . Ture ?
Q2 .
byte b = 1 ;
switch( b)
// does switch take byte as Param ?
Q3.
Strings are immutable , then
why ->
String s1="Mr." ;
s1+=" X" ;
System.out.println (s1); // output is Mr.X
Q4.
if a thread class is thrd
then
thrd t1 = new thrd();
thrd t2 = new thrd();
t1.start() ;
t1.start() ;
// what will happen ? any thing special ?
Thanks
ML



M Lashkar
swati bannore
Ranch Hand

Joined: Oct 18, 2000
Posts: 201

Q1. A method cant be overRidden to be more Private ?
if so ,
class cls {
void aMethod (){}
}
class clsChld extends cls {
X void aMethod(){}
}
// the X can Olny be Private . Ture ?

Answer - Fasle, Methods can not be overridden to be more private.They can be more public!

Q2 .
byte b = 1 ;
switch( b)
// does switch take byte as Param ?

Answer - Yes.
The type of the expression in a switch statement must be char, byte, short, or int. It will be converted to an int before it is compared to the case constants.

Q3.
Strings are immutable , then
why ->
String s1="Mr." ;
s1+=" X" ;
System.out.println (s1); // output is Mr.X

Answer - Strings ARE immutable.Here, a new string is created in a pool.

Q4.
if a thread class is thrd
then
thrd t1 = new thrd();
thrd t2 = new thrd();
t1.start() ;
t1.start() ;
// what will happen ? any thing special ?
Thanks

Answer - Nothing special ! You are creating two threads here.
Thanx

Swati Kale
SCJP
SCWCD
Vedhas Pitkar
Ranch Hand

Joined: Jan 27, 2001
Posts: 445
Good Explanation ,Swati!
A overridden meth can be made more public not private.
I would like to add on the switch part that the case is always checked with the switch part whether it is in range or not.If not ,the compiler issues a error.
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: Little 4Qs