Arulkumar Gopalan

Can you compile & execute the code?

First appropriate declaration; then comes initialization.

Why i's value is printed as 10 instead of 11 at line4?
But, i's value is printed as 11 if different variable is used?

public class SameVariableIncrement{ public static void main ( String args[ ] ) { int i = 10 ; // line 1 i = i++ ; // line 2 System.out. println ( "line 2.1 i= "+i ); // line 2.1 (Prints 10) i = i++ ; // line 3 System.out. println ( "line 4 i= "+i ); // line 4 (Prints 10) SameVariableIncrement2.main(); } } class SameVariableIncrement2{ public static void main () { int j=0, i = 10 ; // line 1 i = i++ ; // line 2 System.out. println ("line 2.1 i= "+ i ); // line 2.1 (Prints 10) j = i++ ; // line 3 //Using different vairable increments value of i System.out. println ("line 4 j= "+ j ); // line 4 (Prints 10) System.out. println ( "line 5 i= "+i +" -Using different vairable increments value of i"); // line 5 (Prints 11) } }

Thx!

Why final keyword is accepted with private?

Private methods are not accessible outside of it's class, including to it's own subclasses. So, Overridding of a private method is not possible. Then, why Java accepts private & final kewords together in method declaration?

Note: Asking this question, because certain combination are not accepted by the java compiler like, e.g abstract & static keywords. (but don't discuss about abstract & static here, since the concepts are different in both.)

Apparently, am spending more time to know my score than the time spent for exam preparation. I have given up, and just waiting for certification kit to know the score!

But, of course, authentication is required for security & to identify candidates.

May be, SUN could provide a SSN (Sun Security Number) to identify candidates in all applications/system they have!

This is what I see in "Download Logos" section:

Sun Certified Associate for Java Platform, Standard Edition
There are no logos available for this program.
---

So, Isn't it available for SCJA?
If so, I don't understand why?
Is this the same case with other beta exams?

Thx.

[ September 02, 2005: Message edited by: Arulkumar Gopalan ]
[ September 02, 2005: Message edited by: Arulkumar Gopalan ]

Yes, I could also logon to the database just now and able to see the results. My first SUN certification, of course FREE $$$!

Thanks to every one!

Here is an example of how variables are hidden/dominated in methods.
public class Main1 { static String str = "My String OBJECT"; public static void main(String[] args) { System.out.println(str); //line 1 System.out.println(go()); System.out.println(str); //line 1 System.out.println(go(str)); System.out.println(str); //line 1 } static String go() //global variable str is used. { str = str + " 2"; //line 2 return str; } static String go(String str) //Local variable str is used with in method. (global variable is hidden inside) { str = str + " 2"; //line 2 return str; } }

Reference for the rows of the array is already created and compiler is aware of the same. You are printing the second row which does not have any value. So, null is getting printed.

But, incase if the array declaration is complete as below, you would not get null.
int i[][] = new int[2][2];

public void bMethod() { synchronized(this) { i--; } }
The above code(originally posted) has same effect as the code below, since no other code is present in bMethod()
public synchronized void bMethod() { i--; }
so, bMethod() is not concurrently executed.

Actually, threads are executed concurrently. But 'synchronized' puts a lock in the synchronized method(or synchronized block) and does not allow other threads to access that piece of code until the current thread releases the lock.

Does it answer your question?

Am using 1.5.0_04

Having said abstract key word is used only for "to avoid creating instance of a class". But, below explanation says, that should be achieved using private constructor, not through abstract.

A class type should be declared abstract only if the intent is that subclasses can be created to complete the implementation. If the intent is simply to prevent instantiation of a class, the proper way to express this is to declare a constructor (�8.8.10) of no arguments, make it private, never invoke it, and declare no other constructors. A class of this form usually contains class methods and variables. The class Math is an example of a class that cannot be instantiated; its declaration looks like this:
public final class Math { private Math() { }// never instantiate this class . . . declarations of class variables and methods . . . }

This is just FYI!

boolean equals(Object o) method also uses the hashing mechanism to compare object references.

Priya,

The code provided explains which you said somethings are not possible.
- code has two different type of arrays (Integer and int)
- Integer array accepts the int value
- int array accepts the Integer value

Please read your explanation throughly and check the code provided below. For your understanding, I have given the println methods also. Execute the code and let me know if you have any questions.

class Chumma { public static void main(String ss[]) { System.out.println("start"); Integer x[] = new Integer[4]; //Object array x[0] = 100; //Assigning an int value to the object x[1] = (int)(Math.random() * 100); //11 x[2] = new Double((Math.random() * 100)).intValue(); //12 //Converting double to int with out type casting x[3] = new Integer(new Double((Math.random() * 100)).intValue()); //13 //Assigning an Integer object int xx[] = new int[4]; //prmitive array xx[0] = 101; xx[1] = (int)(Math.random() * 101); //21 xx[2] = new Double((Math.random() * 101)).intValue(); //22 //Converting double to int with out type casting xx[3] = new Integer(new Double((Math.random() * 101)).intValue()); //23 //Assigning an Integer object for(int iarrElement : x) { System.out.print("["+ iarrElement +"] "); } System.out.println(); for(int iarrElement : xx) { System.out.print("["+ iarrElement +"] "); } System.out.println("\nend"); } }

Author is right!