Kishore Kumar

Hi

Can any one please let me know any link/book to learn Oracle Toplink tutorial.

I am using WAS 6 with db2.

I've used currentSchema i.e deafault schema property in Datasource for JDBC connectiion pooling. Is there any way to fetch this value from java. I need to send this value to VB from java.

I still had a bit of confusion here.
x = true || true && false ; // [B]Assigns true to x, true && false is never worked through here[/B]


Here Ronlad said true && false is never worked. But && is having higher precedence than ||. So it should be evaluated first. and then || should be evaluated.

Now consider this example:

int x = 4 + 2 - 8 / 2
Here first operator / is having higher precedence than + or -. So first expression becomes
x = 4 + 2 - 4
Now x = 2.

So in the same way, since && is haing higher precendence than ||, it should be evaluated. Some body please correct me if i am wrong.

I am also getting the warning message during compiling and the output is also 12.
I am using java 1.5 version.

Main.java:7: warning: go(int[]) in
method is missing '...'
public int go(int [] d){
^
1 warning


Can any one tell me why i am getting this warning message.

Hi,
Actually C1 object is eligible for Garbage Collection. But, C3 gets assigned null, and also C3 is not referring to any object. So there is no object ,eans, no garbage collection for C3.
Coming to second object which is eligible for garbage collection is the wrapper class object Short which is a member variable is eligible for GC.

I hope i explained clearly.

I read like this about finalize method:

finalize is called only once for an object before it is garbage collected. If any exception is thrown in finalize, the object is still eligible for garbage collection (at the discretion of gc). The garbage collector thread runs independent of any application. So it simply ignores the exception and collects the objects if possible.

I am not sure about it.

abstract class can have a private constructor. But that class cannot be extended by another class. Instead add a static inner class inside the abstact class and extend that abstract class.

abstract class Base{ public abstract void set(); private Base(){ System.out.println("Private Constructor!"); } static class Derived extends Base{ public void set(){ System.out.println("set() method implemented!"); } } public static void main(String[] args){ new Base.Derived().set(); } }

This is a small sample code.

Hi,

In this case that's normal behavior , even if you comment the notifyAll, because, [B]after the run() method, the thread Calculator is dead, so all the thread waiting for him will resume their execution, even if they are not notified.[/B] In other words : Reader's thread will wait for Caclculator only if this one is Alive, otherwise there is no need to wait.

Then i tried with this example. If i remove comment line#1. Program is executed completely. but if i comment line #1, program waits for the thread's notification. Can you explain why this is so here.

class MyThread implements Runnable { public void run(){ try{ synchronized(this){ //System.out.println("Lock Released"); System.out.println("Lock Attained1 on " + this.toString()); //notifyAll(); //line #1 System.out.println("Lock Released1 on " + this.toString() ); }System.out.println("This Thread has completed" ); }catch(Exception e){ e.printStackTrace(); } } public String toString(){ return "MyThread"; } } class RunThis implements Runnable{ MyThread obj = null; public void run(){ try{ synchronized(obj){ System.out.println("Lock Attained on " + obj.toString()); obj.wait(); System.out.println("Lock Released on "+obj.toString()); } }catch(Exception e){ e.printStackTrace(); } } public String toString(){ return "RunThis"; } public static void main(String[] args){ MyThread obj = new MyThread(); RunThis obj1 = new RunThis(); obj1.obj = obj; Thread t = new Thread(obj); Thread t1 = new Thread(obj1); t1.start(); t.start(); } }

Hi,
This code is from the K&B,


class Reader extends Thread { Calculator c; public Reader(Calculator calc){ c = calc; } public void run(){ synchronized(c){ try{ System.out.println("Waiting for calculation..."); c.wait(); }catch(InterruptedException e) {} System.out.println("Total is: " + c.total); } } public static void main(String [] args) { Calculator calculator = new Calculator(); new Reader(calculator).start(); new Reader(calculator).start(); new Reader(calculator).start(); calculator.start(); } } class Calculator extends Thread { int total; public void run() { synchronized(this) { for(int i=0;i<100;i++) { total += i; } notifyAll(); // =====What if I comment this===== } } }


OUTPUT:
Waiting for calculation...
Waiting for calculation...
Waiting for calculation...
Total is: 4950
Total is: 4950
Total is: 4950

Well, this is OK... But even when I comment the notifyAll() method call,
I get the same output.. Actually i expected the output to be
OUTPUT:
Waiting for calculation...
Waiting for calculation...
Waiting for calculation...

and the program never stops since there is no notify/notifyAll method called. Instead i get t he same out put. Can any one please tell me why it is so?

Hi,
boolean b = false;
String s = (b=!b)?(b=!b)?"Hello":"hello" b=!b)?"world":"World";

Terinary operators have assositivity from Right to left.
So, the above expression becomes

String s = (b=!b)?((b=!b)?"Hello":"hello") (b=!b)?"world":"World");
So first, this executes:-((b=!b)?"world":"World")
Result is: world and boolean b = true.
Expression becomes:
String s = (b=!b)?((b=!b)?"Hello":"hello"): world
Now, (b=!b)?"Hello":"hello" executes:
Result is: hello and boolean b = false.
So expression becomes: String s = (b=!b)? "hello":"world"
Finally out put is: hello.

I hope i explained clearly.

Two reference variable pointing to the same Short object.
c1.short and c2.short are pointing to same object.
If one is assigned to null, othere will be still pointing to same object.I guess there is only one Short object created. So only 1 object is garbage collected. Any one can correct me if i am wrong.

Hi every one,
I want to throw some points on this. First of all object pointed by c2 reference is not eligible for GC. I think only one object is eligible for GC. Instance variable stroy is not eligible for GC. See the out put of the below code.
class CardBoard { Short story=5; CardBoard go(CardBoard cb){ cb=null; return cb; } public static void main(String args[]){ CardBoard c1 = new CardBoard(); CardBoard c2 = new CardBoard(); CardBoard c3 = c1.go(c2); System.out.println(c1.story == c2.story); //#line 1 c1 = null; System.out.println(c2.story); } }

Value printed at line 1 is true. that means only one Short object is created. So, since c2 object is still not Garbage collected, we can refer to that Short stroy object using c2 reference. Finally, i conclude only one object is eligible for GC.

Now consider the output of this program:
class CardBoard { Short story=[B]128[/B]; CardBoard go(CardBoard cb){ cb=null; return cb; } public static void main(String args[]){ CardBoard c1 = new CardBoard(); CardBoard c2 = new CardBoard(); CardBoard c3 = c1.go(c2); System.out.println(c1.story == c2.story); //#line 1 c1 = null; System.out.println(c2.story); } }

Now Value printed at line 1 is false. So there are 2 Short story object created one for c1 and other for c2. As c1 is eligible for GC 1 short story object is also eligible for GC. So, a total of 2 objects are eligible for GC.

I can't figure out why if the value of short is >= 128, 2 objects are created. Can any one tell what is happening with Short variable and it's value.

Hi,
I am a new to jsf. I know struts framewor. Now i want to learn jsf. I want some good tutorial on jsf. Can any one send me some good links to jsf tutorials.

Hi,
I have 2 year experience in JAVA/J2EE. I also secured 91% in scjp1.4. Looking forward for change in job in Hyderabad/Bangalore. Can anyone let me know about good job oppurtunities in Hyderabad/Bangalore for JAVA/J2EE.

Hi every one, I cleared scjp1.4 with 91%. Now i want to go for scwcd. Can any one tell me where can i find the good material for scwcd. I am familiar with servlets and jsp. But i want some materials and some mock exams as well.