constructor question

[Sandeep Bhandari]

Q8)Which of the following are valid Constructors?

A1 public Test8(){}
A2 private void Test8(){}
A3 protected Test8(int k){}
A4 Test8(){}

from

http://www.javabeat.net/javabeat/scjp2/mocks/

The answer being given is

A1,A3
what is wrong with "A4" option

[Justin Russo]

Nothing seems wrong to me.. Might be an error in the mock test.

contact the site and see what they say..
[ April 02, 2008: Message edited by: Justin Russo ]

[Akshata Kamat]

A4 is a valid constructor too. must have been missed out

[Sandeep Bhandari]

thanks for replies.
now i am confident.

[ishmayel vemuru]

yes the A4 option is the Valid constructor.
--
Ishmayel

[Sandeep Bhandari]

public class Test14{
static String s ="Instance";
public static void method(String s){
s+="Add";
}
public static void main(String a[]){
Test14 t = new Test14();
s = "New Instance";
String s = "Local";
method(s);
System.out.println(s);
System.out.println(t.s);
}
}
What is output?

A1 Local Instance
A2 Local New Instance
A3 Loca Add New Instance
A4 Compiler Error

from
http://www.javabeat.net/javabeat/scjp2/mocks/scjp_1_4_mock_exam_questions_2.php

What's your take on this question?
I say compiler error because of duplicate variable.

[Avi Sridhar]

Originally posted by Sandeep Bhandari:
public class Test14{
static String s ="Instance";
public static void method(String s){
s+="Add";
}
public static void main(String a[]){
Test14 t = new Test14();
s = "New Instance";
String s = "Local";
method(s);
System.out.println(s);
System.out.println(t.s);
}
}
What is output?

A1 Local Instance
A2 Local New Instance
A3 Loca Add New Instance
A4 Compiler Error

from
http://www.javabeat.net/javabeat/scjp2/mocks/scjp_1_4_mock_exam_questions_2.php

What's your take on this question?
I say compiler error because of duplicate variable.

This program just by simply compiling and running gives

Local
New Instance

I assumed that it will give a compiler error because of the "forward reference" issue

s = "New Instance"
String s = "Local";

first s is initialized and then it is declared.

Please correct me if I am wrong.

how come it is printing

Local
New Instance

Thanks

[Gabriel Claramunt]

Look at the beginning of the class:
static String s ="Instance";

When you do
s = "New Instance"
you're assigning the value "New Instance" to the class variable s

When you do
String s = "Local";
You're declaring a new local String s that "eclipses" the class variable.
The original s variable is still accessible as t.s or better, as Test14.s (since is a static/class variable)

[Avi Sridhar]

Originally posted by Gabriel Claramunt:
Look at the beginning of the class:
static String s ="Instance";

When you do
s = "New Instance"
you're assigning the value "New Instance" to the class variable s

When you do
String s = "Local";
You're declaring a new local String s that "eclipses" the class variable.
The original s variable is still accessible as t.s or better, as Test14.s (since is a static/class variable)

Thanks a lot for your reply. It surely clears up the concept.

[Dinesh Tahiliani]

public class Test14{
static String s ="Instance";
public static void method(String s)
{
s+="Add";
System.out.println(s);
}
public static void main(String a[])
{
Test14 t = new Test14();
s = "New Instance";
//String s = "Local"; -- line 1
method(s);
System.out.println(s);
System.out.println(t.s);
}
}

o/p --
New InstanceAdd
New Instance
New Instance

When i comment the line 1 , i get the above o/p.
****************************************************

public class Test14{
static String s ="Instance";
public static void method(String s)
{
s+="Add";
System.out.println(s);
}
public static void main(String a[])
{
Test14 t = new Test14();
//s = "New Instance"; -- line 2
String s = "Local";
method(s);
System.out.println(s);
System.out.println(t.s);
}
}

o/p --
LocalAdd
Local
Instance

when comment line 2, i get above o/p

I didn't get. String s is static variable so it has one copy to all instances of class.
s="New Instance"
String s="Local"

What these are doing , can you please hlep me out ot understand the concept please...
[ April 02, 2008: Message edited by: Dinesh Tahiliani ]