SCJP journey

Cleared SCJP 86%

2009-01-15T15:51:00.002+05:30

I finally cleared SCJP and closing this blog

as a last post I would mention what I had gone through

the exam was hectic although I saved a lot of time
everywhere I read it is easy probably because whoever said so have gone through several mocks, in my case I do not want to ruin first time experience so I did not give any mocks although 2 came free with my SCJP(Kathy and Birt ) book.

the exam would seem easy for if you have gone through their book(exhaustively).

for brevity and to not misguide you I' ll let this post close because any information can be misinterpreted(and I mean in a wrong way)

Promentric testing location aka SCJP testing location Allahabad UP on Google Map

2008-10-17T04:48:00.003+05:30

This is the link of Prometric testing center of Allahabad , the sole center which conducts SCJP exam in Allahabad(the website shows two but they are one and the same center)

Click Here

Managing join function on threads

2008-10-07T04:13:00.003+05:30

I spent 2 hours trying to figure out how to join a thread at the end of another thread and none of these two is the 'main' thread, after a some miss-and-trials I came up lucky enough with a solution , I know it's jibberish but it works(frankly I expected it to work the other way round but these are the intricacies of OOP)

this is the code.

class MyThread extends Thread{
public void run(){
for(int i=1;i<=500;i++){
System.out.printf("%d %s\n",i,Thread.currentThread().getName());
//try{
// Thread.sleep(50);
//}catch(Exception e){}
}
}
}

public class MyRunnable implements Runnable{

public MyRunnable() {

}

public void run() {
MyThread t= new MyThread(); // added to check join function
t.start();
t.setName("Thread");
try{
t.join();
}catch(Exception e){}

for(int i=1;i<=500;i++){
// try {
//Thread.sleep(5);
// }catch(Exception e){}
//if(i==250)
// t.join();

System.out.printf("%d %s\n",i,Thread.currentThread().getName());
if(i%10==0)Thread.yield();
}
}
}

public class MainClass {
public static void main(String args[])throws InterruptedException{
// MyThread t= new MyThread();
MyRunnable mr = new MyRunnable();
System.out.println("master thread is "+Thread.currentThread().getName());
Thread thread = new Thread(mr);
thread.setName("*runnable");
//t.setName("thread");
//t.setPriority(8);
//thread.setPriority(8);
thread.start();
// t.start();
// t.join();
//t.setPriority(Thread.MAX_PRIORITY);
//t.start(); will throw illegal thread state exception
}
}

the point is the runnable thread sticks to end of 'thread' some intricacy of being a static method but I am not getting a logical answer out of my grey cells, getting back to dwell more.

fixing thread behaviour - novice

2008-10-07T01:37:00.002+05:30

consider these three classes,

public class MyRunnable implements Runnable{

public MyRunnable() {
}

public void run(){
for(int i=1;i<=50;i++){
try {
//Thread.sleep(5);
}catch(Exception e){}
System.out.println(Thread.currentThread().getName());

}
}

}

public class MainClass {
public static void main(String args[]){
MyThread t= new MyThread();
MyRunnable mr = new MyRunnable();
System.out.println("master thread is "+Thread.currentThread().getName());
Thread thread = new Thread(mr);
thread.setName("runnable");
t.setName("thread");
thread.start();
t.start();
t.setPriority(Thread.MAX_PRIORITY);
//t.start(); will throw illegal thread state exception
}
}

class MyThread extends Thread{
public void run(){
for(int i=1;i<=50;i++){
System.out.println(Thread.currentThread().getName());
try{
// Thread.sleep(50);
}catch(Exception e){}
}
}
}

the code is simple but I wrote this code to let thread named "thread" first execute followed by Runnable implemented thread but it all go wrong since I first started thread 'runnable' so it will execute few lines of codes before starting thread 'thread' and my code goes awry, to fix this just uncomment this line

//Thread.sleep(5);

this passes transfers 'runnable' to sleep state(or blocking state) which gives 'main'(yeah!! main is also a thread) thread to start second thread and since it is higher priority so runs to completion till the before returning back to 'runnable'

A little threading experiment

2008-10-07T01:27:00.002+05:30

Consider the following program

public class MainClass {
public static void main(String args[]){
MyThread t= new MyThread();
MyRunnable mr = new MyRunnable();
System.out.println("master thread is" +Thread.currentThread().getName());
Thread thread = new Thread(mr);
thread.start();
t.start();
thread.setName("runnable");
t.setName("thread");
//t.setPriority(Thread.MAX_PRIORITY);
//t.start(); will throw illegal thread state exception
}
}

this code works on classes posted in previous posts(MyThread class and MyRunnable class with only loop running 50 times) and it runs cool with showing variable output, if we run this code then we might get something like an output showing

master thread is main
Thread-1
thread
thre...
......

this Thread-1 is generic name of MyThread class supplied by JVM which shows once loop is executed before reaching the setname function, to fix this up(nothin is guaranteed so this fix might not work but we are just taking extra precautions) transfer the setname function above the code for starting both threads.
.................................................
Thread thread = new Thread(mr);
thread.setName("runnable");
t.setName("thread");
thread.start();
t.start();
//t.setPriority(Thread.MAX_PR.......

which fixes up the mess

Thread in windows

2008-10-06T22:39:00.002+05:30

It seems windows thread mechanism and scheduler is rather lazy or The our lab systems are too powerful (well they are , a 2GB RAM with core 2 quad Intel platforms at it's heart) so I write a simple program to check the behaviour of threads, I implemented simple code including three classes a simple class extending thread interface , a class implementing runnable interface and a main class to keep everything going

following are the code of each of the three classes.

public class MainClass {
public static void main(String args[]){
MyThread t= new MyThread();
MyRunnable mr = new MyRunnable();
Thread thread = new Thread(mr);
t.start();
thread.start();

}
}

public class MyRunnable implements Runnable{

public MyRunnable() {
}
public void run(){
for(int i=1;i<=5000;i++){
System.out.println("runnable is running");
}
}
}

class MyThread extends Thread{
public void run(){
for(int i=1;i<=5000;i++)

System.out.println("The extended thread is running");
}
}

take note of the heavy loop I created in both threads , it is not something to hog your CPU cycles(well it does so) but if I decrease the value by one zero the the ouput seems not of any thread importance , if I reduced loop to 500 , I got 500 lines of "The extended thread is running" followed by 500 lines of "runnable is running" , it seems that either the JDK implementation in windows doesnot like thread much or the underlying thread handling in windows system(if JVM maps thread handling to underlying system) is awkward, however the above code show me some real grace with first "runnable is running" after 638 lines of "The extended thread is running" , that's just an observation, everything else works fine.

SCJP success experience of Sujan Surendran (as posted on javaranch)

2008-09-03T02:31:00.002+05:30

In the afternoon on Saturday the 22th of June, I began making telephone calls to Prometric centers in the city to book a slot for SCJP test for the weekend ahead, 28th or 29th of June (or in the worst case any date before the expiry date on my SCJP coupon, 30th of June). I had got the coupon some eight months before and had forgotten about it for a long time (Ever since I started working, I've forgotten a lot of things of my student life). Unfortunately slots for the weekend were all taken and none were available through out Bangalore. In the end the farthest date before 30th that I could get, was 25th. I got a 3.30 pm afternoon slot. Time was too short and I had to revise a lot of things. I was in a kind of do-or-die situation, and I worked quite hard.

On the morning of 25th I woke up with flu. In the afternoon I left my office a few minutes after lunch so that I'll be on time at the Prometric center. I felt a bit uncomfortable during the test because of sinusitis. But thank God, I had flu on day on which I had the test. Had the flu come before the test date I wouldn't have been able to prepare for the test. I passed SCJP 1.5 with 97%. I was a bit like heart-broken initially for not being able to get 100, but then I was satisfied with what I have got. With only a short time before the test for preparation and flu, 97 sounded like a good score.

Although the two day revision before the test was crucial, the secret to my success is the interest I have in Java since my college days. I always found it very exciting to work on Java. After college, before I started working for a company I spent most of my time working on small Java applications and thought of getting Sun Certification. I also spent one full day at book stores to find the best exam guide. The SCJP study guide (K&B) by Kathy and Bert is a wonderful book not just for SCJP but even otherwise it is an excellent reference/study material for Java developers. I have always loved Java and the book adds to the beauty of Java and makes it a pleasant experience to read through. Thank you, Kathy and Bert.

Regards,
Sujan

This is the success story of Sujan Surendran as posted in javaranch, for the post click here, the person got 97%in his exam...

'instanceOf' is not a keyword

2008-08-01T19:19:00.000+05:30

instanceOf which bumps everywhere when somebody prepare for SCJP 5 is not a keyword rather it can be used as a normal variable name

These all are legal

class instanceOf{}

void instaceOf{<parameter list>}

in both of these example it acts like a normal keyword like foo or bar (or Mesopotamia for Christ's sake)

however instanceof is a keyword

for discussion refer this javaranch thread

[Caption]

The Wierd nature of postfix operator

2008-07-30T16:50:00.002+05:30

while on javaranch today I found a post regarding a question which let everybody's brain fuzzy preparing for java certification (or say SCJP), the wierd behaviour of postfix operator

what is expected by the following code

int x = 1;
x = x++;
System.out.println(x);

as most of beginners my immediate respnse was 2 but then with help of some ranchers and few digging in Java language specification I found that this is not the case, this code prints 1, in fact postfix can be think of like this method

int postfixIncrement() {
int result = x;
 x = x + 1;
 return result;
}
where it returns original value, so if you typex
x=x++;
what hapens is x++ is calculated so x is incremented and stored in
 a temorary variable and then it returns original(not incremented x's value
which in this case is assigned to x itself so the new value of x is overwritten by
x's original value,
for example observe this code
in x=1;
int y = x++;
System.out.println(x);

here x is not overwritten so it will print 1 and y's value is 2(as expected or rather say unexpected)

reference:rizzoweb

and for detailed explanation refer JLS(Java Language Specification)

containsAll clarification fro SCJP

2008-07-27T02:01:00.001+05:30

Collection:containsAll (Programmer Certification (SCJP) forum at JavaRanch)

If you look at the Collection interface, the containsAll method has signature:

code:

public boolean containsAll(Collection c)

therefore you can check against any type of collection that contains Objects. It could (but doesn't) limit the collection to the E type parameter.
It also says that the ClassCastException is optional so therefore dependent upon the implementation.

Incidentally, the containsAll method in ArrayList is inherited from the AbstractCollection so you may want to look there for more info.

One way you could think about the implementation is like so (you will be able to find the actual source somewhere):

code:

for(Object o:c){
if(!this.contains(o){
return false;
}
}
return true;

source : javaranch
forum : SCJP

ques for SCJP

2008-07-15T19:00:00.001+05:30

Overriding Vs. overloading (Programmer Certification (SCJP) forum at JavaRanch)

public void call (String n, int i) { }

public void call (int i, String n) { }

Is this overloading or Overriding?

It is overloading since method signatures are different in terms of argument.

AVERAGE SALARY AFTER CERTIFICATIONS

2008-07-15T15:26:00.001+05:30

Certification Salary Survey Results

his table shows the breakdown of salaries based on the first two certifications entered by a respondent.

* The first certification entered is listed in the "Cert1" column with any second certifications listed in the "Cert2" column.
* For certifications with no second cert listed, or for those who did not enter a salary, you will find an entry of "--".
* The amounts in bold represent the average salary for Cert1, regardless of the presence of a second certification.

To interpret the results look at the Brainbench Cert listed below. The average salary for all those with a Brainbench cert as their first selection, regardless of any additional certs, is $36,176.92. However, one person also had a A+ cert in addition to the Brainbench cert. They earned $30,000. 11 people had only a Brainbench cert with no other certs and averaged $38,027.27.

scroll to the bottom of list for sun java certifications including SCJP , SCJD

to view table click here

Technorati Tags: scjp salary, scjp income, scjp, java certification salary, java certification income, java certification

SCJP is disappointing more candidates

2008-07-14T03:57:00.004+05:30

Either human beings have become more brave or SUN is going Stricter TO distribute their certifications, but past week or so seemed to be a warning at least for me , In this period I have seen at seen at least three confessions of person confessing their failure in securing pass percentage In SCJP, either 310-065 is more harder or just time of the year but given that I am no veteran in this field and had just started it seems to be pretty scary time for me, as I am scheduled to give my exam within a month, My last post was about SCJP fail experience, but that seems just a tipline of chain, lets forget everything and start afresh, I have full faith in Kathy and Bert that they will not disappoint me of my dollars (the fee was huge), just posting because I was out of touch for few days because I had no internet connection but that seems more productive since I finished more than half K&B in a week( that's pretty fast for me, don't laugh!!)
good night, going to sleep...

SCJP Success story of Ralph Jaus

2008-06-30T16:45:00.001+05:30

Cleared SCJP 5 with 98% - experiences (Sun Certification Results forum at JavaRanch)

Hi all,

on Friday I cleared SCJP with 98%. I'm so happy. Manny thanks to the forum for all the help.

Here are some experiences:

- I didn't expect that score at all. My scores in mock exams had been much
worse:

Whizlabs: 90%, 83, 85, 90, 86, 96
K&B master exams: 76, 78
sun:: 95

- The real exam is easier than these mock exams. Nevertheless, best what
you can do for preparation: Solve as much mock exams as possible. That
will provide you with the necessary know how and ability to concentrate
on that kind of questiions over three hours.

- Whizlabs is a good tool. For example, a question about threads was nearly
identical with a question on the exam.

- On of the best free mock exams I know is http://www.danchisholm.net
Besides the new Java 5 features it covers a great deal of the stuff.

- I analysed each of my mistakes in the mock exams and learned the correct
Java behavior.

- According to drag and drop questions enthuware is close to the prometric
surface. One important difference: At enthuware (at least in my version
from 03/2008) in order to change a dragged value you have to clear
everything. At prometric it is possible to change single values. That's a
great advantage.

- As it has been complained in the forum many times, if you reopen a drag-
and-drop-window, all your preceding choices will be deleted. That's
completely unacceptable. I hope sun will improve this surface soon.

- There are questions of the following layout: Little code with 4 or 5
lines and the multiple choice questions are on the main page and the
other, comprehensive code is on a second window that has to be opened
separately.

Now the questions concerned lines numbers in the code of the main page.
But I was absolutely focused on the large code of the other window and
couldn't find the questionable line numbers there. This was quite
confusing. Just at a later question with the same layout I discovered the
pattern and could solve the former question.

- The exam lasted 210 minutes. I needed about 200 minutes. I advise to
solve each question completely as it occurs and to minimize the number of
questions that you want to reconsider after you worked through all
questions.

- Questions about threads were ordered sequentially and were centered
around question 10. Since they needed a lot of consideration I was quite
slow at the beginning. Don't worry in such a situation. The other
questions can be answered much faster.

- In mock exams I was frequently confronted with questions about methods of
String, collection, thread and other classes that hadn't been handeled in
K&B. In my exam there also encountered one question (about collections)
with such a method. I guess that was the question I answered incorrect.

Good luck for your exams.

Ralph

Source : JavaRanch Saloon

confessions of an SCJP failed person

2008-06-29T23:53:00.001+05:30

How to fail in SCJP... (Programmer Certification (SCJP) forum at JavaRanch)

How to fail in SCJP?
•Start studying when the exam is just 5 days apart! Imagine that SCJP 6 is just another exam and you do not have to study hard for it.
•As you are a champ in C or Data structures or C++ and as you have prepared for Java paper at your university exams just few months back, you should assume that you will easily cram it!
•Be (over-)confident about your intelligence (in fact you should keep on reminding yourself about all those difficult questions you have solved so easily and all the programming achievements at your college and project (again which should not be in Java!!!)).
•Do not solve the problems practically on your PC, just go on reading them.
•Presume that the coordinators at the exam center will be very obliging to you and you will be having enough of water to drink and air to breathe in the cabin of examination. You may also suppose that if the testing software throws the ‘error 708’ they will accept that it is an error that can in no way be triggered by the poor chap (of course at exam hour, its you!) who is trying to figure out what’s going on! [banghead] [banghead]
•Without appreciating the essence of codes and all the examples, just try to learn the two-minute drill and other stuff from K&B. Become happy when someone keeps on using the term “on the exam…” and do not worry about the overall knowledge you should possess about a given API or any other stuff. Also waste lots of time in understanding the befuddling language used in the book.
•Do not read Khalid Mughal.
•Believe that someone on Javaranch will help you out when you yourself don’t know what the problem is.
•Dream that the dumps you have arranged from your certified friend are the questions that the Sun Microsystems will put on exam!
•In spite of a very strict deadline on your head and a very tense scenario (you know your job depends on this certificate), do not feel stressed. You can still spend hours after hours thinking about the charismatic girl at your workplace whom you like so much…
•Do not forget to hunt for her in her college and at any other place where you might have a glance of her right on the day of exam!!! Her winsome smile and the beauteous moment will do the above mentioned job for you. Even if you are unable to find her, the target is achieved!
•Take keen interest and keep smiling when you see a post like this! Also don’t forget to reply… [argh] [argh]

--------------------

SCJP 6 failed - 48% - 28/06/2008

"In great attempts it is glorious even to fail. - Cassius Longinus"

The above post is by Bhushan Chhajed who failed in SCJP 6 on 28 june 2008
it seems funny but it is reality, I presume that I will be giving this paper within 2 months and yet not serious about it yet I and some of you should take a lesson from this person.

SCJP for Java Enthusiast:received my sun voucher

2008-06-26T22:04:00.001+05:30

Today I received My Sun voucher For Java Although I did not saw it but it is a my home bought from NIIT shakti Nagar New Delhi, It came up with fairly good discount costing only Rs 4500 as compared to general Price of INR 7200, My initial impressions of exam are that ity is fairly conceptual in nature and 2 months preparation if you have a normal understanding of language is fair enough to clear it(It is not personal experience but what I got from different blogs, Success stories scattered around here and there over Internet

Now some detail of Exam itself (Not by me, just copied from somewhere)
PS:for the font, just tryng a new one.

Sun Certified Java Programmer (SCJP)

The Sun Certified Java Programmer (SCJP) exam is the entry level Java exam and is a prerequisite to a number of the other Java-related certifications. SCJP 6, designated CX-310-065 by Sun, was released in December 2007.

It is designed to have a fairly detailed test of basic knowledge of the essentials of the Java programming language. It tests looping constructs and variables, and does not cover specific technologies such as GUI creation, Web or network programming.

It is assessed through an automatically administered multiple-choice test system and consists of 72 questions which the candidate has 210 minutes to answer. At least 47 questions are needed to be correct to pass (around 65%). The exam is taken at a Prometric test center, and to take the test a candidate must buy a voucher from Sun (approximately US$200 in the US, but £150 (excluding VAT) in the UK) and book the test at least a week in advance. The test consists of multiple choice and drag-and-drop questions, the latter comprising 20-25% of the questions.

The SCJP 5 exam tests a candidate on knowledge of declarations, access control, object orientation, assignments, operators, flow control, assertions, string handling, I/O, parsing, formatting, generics, collections, inner classes, threads and the JDK tools[1]. The test is available in English, Japanese, Chinese, German, Korean, Portuguese and Spanish.

Previous versions

There have been a number of previous versions of the SCJP. The current version, SCJP 6.0, is aimed at the JDK 6.0 release of Java. It introduces new topics covering Console, NavigableSet, and NavigableMap.

SCJP 5.0 (designated CX-310-055) was based on JDK 5. It introduced variable arguments, autoboxing, and generic types, and dropped the bit shifting topics from previous exams.

SCJP 1.4 (designated CX-310-035) was based on JDK 1.4. Compared to the previous version of the exam, SCJP 1.2, it dropped questions on GUI topics and shifted the emphasis towards core language features[3]. SCJP 1.4 features 61 questions to be answered within 120 minutes. 32 questions or more (52%) need to be answered correctly in order to pass.

SCJP 1.2 (designated CX-310-025) was based on JDK 1.2, and was first live on 15 June 2000. The exam had 59 questions (both multiple choice and short answer) to be answered within two hours. The pass mark was 61 percent. However, exam 310-025 has been withdrawn from the market; certified professionals can retain their certification and use the title, but this version is no longer being offered.

Float from javadoc

2008-06-25T12:30:00.001+05:30

Float (Java 2 Platform SE 5.0)

Note that in most cases, for two instances of class Float, f1 and f2, the value of f1.equals(f2) is true if and only if

f1.floatValue() == f2.floatValue()

also has the value true. However, there are two exceptions:

* If f1 and f2 both represent Float.NaN, then the equals method returns true, even though Float.NaN==Float.NaN has the value false.
* If f1 represents +0.0f while f2 represents -0.0f, or vice versa, the equal test has the value false, even though 0.0f==-0.0f has the value true.

John Meyers cool question

2008-06-23T23:15:00.001+05:30

int[] a = null , b [] = null;
b = a;
System.out.println( b );

Choose all that apply
A) Runtime NullPointerException
B) Prints null
C)Compile time error

now explanation:

Look at the code carefully. Its a bit tricky one.

int [] a=null,b[]=null; is equivalent to int [] a =null; int[] b[]=null;

So a is a one dimensional array whereas b is a two dimensional array. Its just the way how the compiler interprets it.

hence answer is C

By-
Hemnathbabu Kottaiveedu

A note about automatic casting

2008-06-23T22:59:00.001+05:30

The Character class has got just one constructor ( jdk1.2.1 ) which takes a char data type .

Also note that most of the Wrapper class constructors that take a String argument can throw a NumberFormatException ( which is an unchecked exception ) .

result of Math.abs(Integer.MIN_VALUE())

2008-06-23T22:24:00.001+05:30

is Integer.MIN_VALUE()
that is -2147483648

this is a special case.
because the obvious result is doesn't fall into integer domain

Note:Integer max value is 2147483647 and following statement result in 1 arithmatic value higher so compiler doesn't dop absolute wrapping.

Float rules

2008-06-21T16:13:00.001+05:30

primitive casting (Programmer Certification (SCJP) forum at JavaRanch)

How float is considered a bigger variable than int?
Because both have the same 32bits.

Ans
It's not based on bits, it's based on range -- interestingly, Java doesn't really care much about precision either.

Anyway, the range of an int is from -2,147,483,648 to 2,147,483,647. And the range of a float is from -3.40282346638528860e+38 to +3.40282346638528860e+38.

So, as you can see even though an int and a float are both 32 bits, a float covers a much bigger range. In fact, a float has a bigger range than a long, even though a long is 64 bits and a float is 32 bits.

Kathy and Bates SCJP 5 guide errata list by Bert Bates

2008-06-18T14:49:00.001+05:30

K & B, SCJP 5 - Errata: Updated 7/28/06 (Programmer Certification (SCJP) forum at JavaRanch)

Hi Guys,

Thank you all for your sharp eyes! Below is the updated errata list for our SCJP 5 book.

I'm going to leave this thread locked - so it will be readable but not update-able. What I'd like to request is that if you have a doubt about this errata list or if you think you've found another error, please start another thread and include "Doubt in K&B SCJP 5: topic _____" in the Subject of the thread. That way we can all discuss it and decide whether it's a real errata or not. What we've discovered is that some fraction of the "errata" that are reporting are actually not errata, so this is an attempt to keep the errata list as useful as possible. Once we've agreed that a new errata has been found, we'll add it to this list.

Some of the errata that come in are hard for us to deal with. We want the errata list to be as useful as possible, so some very minor typos are excluded from this list (although they will be fixed in the next printing). In addition, some people have found exceptions to statements in the book, but they are statements that are true as far as the exam is concerned. I'd like to use one of Kristian's erratas as an example (BTW, thanks Kristian for all your thorough research and help with these errata!): Kristian has pointed out that a method-local inner class can have the strictfp modifier. While this is (probably) true, it's not on the exam. We want to keep the book as focused as possible, so this kind of rare exception is a little tricky. What we think we're going to do in the reprint is add something like "While it's not on the exam..." when we need to clarify this kind of thing.

Finally, we're sorry for every errata in the book! We try really hard to find them all before publication, and our crack review team does the same. While we aren't making any excuses, we do believe that this particular book gets a lot more public scrutiny than most other tech books, which results in a more extensive errata list.

Again, we're going to lock this thread, but we urge you to create new "K&B doubt" threads for any related discussions!

Thanks,

Bert and Kathy

SCJP 5 - Errata 7/28/06

(New since April marked with an * after the page number)

page...type......description

..9....clarify...Listener methods must end in "Listener"

.14.*..bug.......2nd para. was: Apart from using...in Chapter 10, you can do one of...
...........................s/b: You can do one of two things...

.41....typo......2nd declaration s/b: final int recordNumber

.45....x-ref.....Synchronized para. s/b: Chapter 9

.59....x-ref.....Volatile para. s/b: Chapter 9

.61.*..bug.......Middle para. s/b: The key point to remember is that an enum that isn't enclosed in a class, can be...

.62.*..bug.......After first code s/b: ...of the enum declaration, when no other declarations for this enum follow
&65....clarify...comment in code s/b: ...REQUIRED when more code follows

.74....bug.......Q-2: answers A-D were: public Bark speak()...
& 77...............................s/b: public void speak()...

.94....clarify...code was: private Halter myHalter;
......................s/b: private Halter myHalter = new Halter();

115....clarify...last sentence before exam watch s/b:

If any superclass in its inheritance tree has already provided concrete (i.e., non-abstract) method implementations, then, regardless of whether the superclass declares that it implements the interface, the subclass is under no obligation to re-implement (override) those methods.

115....bug.......exam watch was: a.doDogStuff();
............................s/b: d.doDogStuff();

133....bug.......3rd row, 2nd column was: class Foo {
.....................................s/b: public class Foo {

174....clarify...line 15 s/b: dog.setName("Aiko");

216....bug.......Starting at 2nd sentence "As we'll cover..." remove that sentence and the code down to the next heading.

217.*..typo......figure 3-4, myDogs(0) s/b: myDogs[0]

229.*..clarify...2nd to last para.: Non-"true" String constructors equate to "false"

233....bug.......In table 3-3, valueOf for Boolean does not throw NFE

234....bug.......1st two S.o.p.'s s/b: ("y = " + y);

235.*..typo......2nd para. "So, under the covers..." was: "i++", s/b: "y++"

236....clarify...Sentence before bullet points s/b: In order to save memory, two instances of the following wrapper objects, created through autoboxing, will always be equal...

236....clarify...Add this sentence: When == is used to compare a primitive to a wrapper object, the wrapper object will be unwrapped to its primitive value, and the comparison will be made between the two primitives' values.

240.*..typo......Para. after "Byte, Byte", 1t sentence, "int" s/b "byte".

258....clarify...2nd boxing bullet s/b: Using == with wrappers created through autoboxing is tricky; those with small values...

259....clarify...Q-2: code s/b: Short story = 200;
& 266

322....clarify...Near the bottom of the exam watch, sentence s/b: But the only variables that can be assigned (rather than tested against something else) are a boolean or a Boolean; all other...

364....typo......code: doStuff() s/b: doStuff();

370....x-ref.....3rd row (IllegalArgumentException) s/b: (This chapter)
.................6th row (NumberFormatException) s/b: (Chapter 3, "Assignments")

381....bug.......code s/b:

switch(x) {
case 2: y = 3; break;
case 3: y = 9; break;
case 4: y = 27; break;
default: assert false; // we're never supposed to get here
}

421....typo...... bottom of page, s/b: x+= " ocean";

439....bug.......2nd 2. s/b: Create a Writer or a Stream. Specifically, create a FileWriter, a PrintWriter, or a FileOutputStream.

454....bug.......2nd paragraph s/b: ...(unless you implement readObject())...

472....bug......."Finding stuff" bullet, last sentence s/b: We'll use the java.util.regex.Pattern , java.util.regex.Matcher, and java.util.Scanner classes to help us find stuff.

492....bug.......Last paragraph s/b: ...and to deserialize an object invoke readObject().

497....bug.......6th bullet: was matcher() s/b: matches()

505....typo......top of page: was: "dir1" and "dir1"
& 517.........................s/b: "dir1" and "dir2"

507.*..bug.......F & G, replace "override" with "implement" and in the answer for A, B, D, and E:
& 520............s/b: ...you don't implement the defaultReadObject() method, you call it from within the readObject() method...

528....typo......2nd line: moofvalue() s/b: getMoofValue()

538....bug.......In figure, LinkedHashMap s/b a subclass of HashMap

562....bug.......After big code listing, s/b: ...not predictable: HashSets do not guarantee any ordering.

574....big bug...The top 2/3 of the page uses a HashSet / Set example. It should be using an ArrayList / List example, so replace 10 occurrences of "Set" with "List", and replace 2 occurrences of "HashSet" with "ArrayList".

581....clarify...Exam watch should be: ...even if that Object reference refers to an Integer (or some other wrapper object) on the heap.

620....bug.......Q-16: method declaration s/b:
& 634
public static List process(List nums)

631....bug.......A-13, end of answer s/b: are not defined in the Arrays or Collections classes. (Objective 6.5)

649.*..bug.......Last sentence in exam watch s/b: It's rare to see semicolons following curly braces.

665.*..clarify...Answer 1, B, remove the sentence beginning: When you instantiate a nested...

669....typo......Answer s/b: A,B,D,E, and F are incorrect

682.*..bug.......In exam watch, code s/b: Thread t = new Thread(); t.run();

711....x-ref.....item 5 s/b: ...Chapter 6...

752....bug.......Answers 13 & 17: IllegalThreadStateException s/b:
& 757 IllegalMonitorStateException

783....clarify...Q-4, D. s/b: D. _A.
& 792

787....bug.......Q-10, This is really a question about java, not javac.
796 & 797........Change all references from javac to java.

--------------------

The above post is by Bert Bates co-author of legendary SCJP 5 preparation guide and errata is posted by himself in Javaranch forum in this thread
and the forum is best part of their website with actiev involvement of members and authors

JavaRanch FAQ : Scjp Faq

2008-06-18T13:30:00.001+05:30

JavaRanch FAQ : Scjp Faq

What are some potential trips/traps in the SCJP exam?

* Two top-level public classes cannot be in the same source file.
* main() cannot call an instance (non-static) method.
* Methods can have the same name as the constructor(s).
* Watch for thread initiation with classes that don't have a run() method.
* Local classes cannot access non-final variables.
* Case statements must have values within permissible range.
* Watch for Math class being an option for immutable classes.
* instanceOf is not the same as instanceof.
* Constructors can be private.
* Assignment statements can be mistaken for a comparison; e.g., if(a=true)...
* Watch for System.exit() in try-catch-finally blocks.
* Watch for uninitialized variable references with no path of proper initialization.
* Order of try-catch-finally blocks matters.
* main() can be declared final.
* -0.0 == 0.0 is true.
* A class without abstract methods can still be declared abstract.
* RandomAccessFile descends from Object and implements DataInput and DataOutput.
* Map does not implement Collection.
* Dictionary is a class, not an interface.
* Collection (singular) is an Interface, but Collections (plural) is a helper class.
* Class declarations can come in any order (e.g., derived first, base next, etc.).
* Forward references to variables gives a compiler error.
* Multi-dimensional arrays can be "sparse" -- i.e., if you imagine the array as a matrix, every row need not have the same number of columns.
* Arrays, whether local or class-level, are always initialized
* Strings are initialized to null, not empty string.
* An empty string is not the same as a null reference.
* A declaration cannot be labelled.
* continue must be in a loop (e.g., for, do, while). It cannot appear in case constructs.
* Primitive array types can never be assigned to each other, even though the primitives themselves can be assigned. For example, ArrayofLongPrimitives = ArrayofIntegerPrimitives gives compiler error even though longvar = intvar is perfectly valid.
* A constructor can throw any exception.
* Initializer blocks are executed in the order of declaration.
* Instance initializers are executed only if an object is constructed.
* All comparisons involving NaN and a non-NaN always result in false.
* Default type of a numeric literal with a decimal point is double.
* int and long operations / and % can throw an ArithmeticException, while float and double / and % never will (even in case of division by zero).
* == gives compiler error if the operands are cast-incompatible.
* You can never cast objects of sibling classes (sharing the same parent).
* equals() returns false if the object types are different. It does not raise a compiler error.
* No inner class can have a static member.
* File class has no methods to deal with the contents of the file.
* InputStream and OutputStream are abstract classes, while DataInput and DataOutput are interfaces.

this is for my later recollection since I am also looking forward for this exam
Courtesy:Javaranch

SCJP contact information in india

2008-06-18T12:37:00.001+05:30

Training Global Contacts

India
Sun Microsystems India Pvt. Ltd
Sun Learning Services
6th Floor, Prestige Obelisk,
No.3, Kasturba Road,
Bangalore 560 001, India

Telephone: (91-80) 6693-0600
Facsimile: (91-80) 6693-0655 / 66
Toll free: 1800-425-1234 or 080-4402-1234
E-mail: Edu_Enquiry_IN@sun.com
Web site: in.sun.com/training

install sun java in your linux box

2008-04-11T16:23:00.001+05:30

I have a problem when everytime I have to install linux on my ubntu box,I have to let synaptic to download and install sun-java jre and netbeans and believe me, here it takes a lot of time, almost a day so based on some website I have downloaded sun sun-java-6 tarball and created the debian binary from it, You can download it ubuntu repository just double click and gdebi will install it and other dependencise,this is sun-java-6update 3 release. Then you can easily install netbeans for linux and enjoy your development ready computer

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