"Top Ten Topics that Everyone Thinks are on the SCJP Exam, but Aren't "- Bert Bates

[La Vish]

I like the idea of Bert.
When you read the exam objectives and study accordingly everything looks hunky dory.But when you start taking the various mock exams you start getting side tracked especially when you score low marks on them.When I took some of the tougher mock exams I felt confused- do I read that topic? do I go deep into that topic? what if that topic comes up in the exam?etc.
Ofcourse, reading K&B book reassures you about what is in and what is not but when you start participating in the discussions, read the questions thrown up for discussions or do a mock exams the doubts surface.
I am sure based on the various discussions available in this forum, K&B would be able to come with a list of "Relax guys, they are not in the exam" list.
Good on you Bert!

[John Lee]

Be careful!
"Top Ten Topics that Everyone Thinks are not on the SCJP Exam, but Are"

[Dan Chisholm]

I sometimes wonder if the exam objectives were written for employers who are wondering how much they should offer an applicant with a certification. The objectives suggest that a certified programmer is required to know far more than what is really required. For example, the objectives state: "Determine the result of applying any operator (including assignment operators and instance of) to operands of any type class scope or accessibility or any combination of these." A lot of mock exams were written based on the assumption that operators would appear in "any combination" but in reality that is not the case. The exam does not emphasize operator precedence. If you memorize only the top five precedence levels (postfix, unary, cast, multiplication and addition) then you shouldn't have any trouble. Of course, you should still know how to use every operator. You just don't need to know all the levels of precedence.
The real exam does not have garbage collection questions that require knowledge of how the garbage collector handles String constants.
The real exam does not require you to know all of the methods of the Collections Framework. Instead, you just need to know where to use each class in the collections framework.
Early versions of my mock exams went far beyond the requirements for the real exam but more recent versions are more focused. Even so, my mock exams still go a little beyond the requirements. Scores on my exam tend to be about 20 percentage points lower than scores on the real exam. I always suggest that my exam should be used as a learning experience and not as a tool for predicting your score on the real exam.

[Bert Bates]

Ok here's one...
The Sun objectives say that the wrapper class' method getXxx() is on the exam... it's not, but the objectives fail to mention valueOf() which is definitely on the exam

[Robbie kyodo]

Hi
Do we have to know StringTokenizer in 1.4 ?

[Robbie kyodo]

Just come across this topic "reflection"
any idea if it is part of it ?

[Bert Bates]

Robbie -
Two good ones!
StringTokenizer and reflection are both good topics that aren't the exam!
2 more topics to relax about!

[Bert Bates]

Ok, let's revive this idea...
What are the top 'ten' topics that people study in preparation for the SCJP 1.4, that are NOT actually on the exam. I'm guessing that MOST people will want to focus on the topics they really need to focus on.
So, we've come up with the first seven, let's make this interactive, if you have a questionable topic, throw it up here and we'll let you know. If you know for sure that a topic isn't on the exam,we'll add it to the list!
Here are the first seven:
1 - The exam won't mix GC questions in with knowledge about the String constant pool.
2 - The exam won't test your knowledge about methods in the Collections framework, only about how the various collection classes should be used.
3 - The getXxx() methods are NOT on the exam, but valueOf() IS on the exam.
4 - Don't worry about StringTokenizer
5 - Don't worry about reflection
6 - Don't worry about clone()
7 - Don't worry about complex precedence questions, if you know the common, basic precedence rules, you'll be set.

What's next??
-Bert

[Marlene Miller]

Here are my questionable topics. Things we should not know about threads.
1. A thread can own locks on more than one object.
2. wait, notify and notifyAll can be declared in methods that are not synchronized, like this:
synchronized void m1() { m2(); }
void m2() { notifyAll(); }
3. A thread can return from join without waiting.
4. The virtual machine can remove a thread from a wait set outside of a notification, interruption or timeout.
If we answer a question assuming these, we could get the question wrong.
[ August 04, 2003: Message edited by: Marlene Miller ]

[Alton Hernandez]

How about these, are they on the exam?
1. Initializers
2. Casting of Wrapper classes constants e.g. (int)Float.POSITIVE_INFINITY, (float)Integer.MAX_VALUE
3. Modifiers strictfp, volatile, transient, native
4. Iterators methods
5. Not so commonly used String/StringBuffer methods like regionMatches(), replaceAll(), subSequence()
[ August 04, 2003: Message edited by: Alton Hernandez ]

[Bert Bates]

Marlene -
Haven't you taken that test yet? You know, no matter how well you do, Sun will absolutely NOT give you a score higher than 100% !!
Ok, I'm meditating on your questions, they might be a LITTLE too specific, we can't really give away the actual questions... so while I'm meditating, can you think about rephrasing them at a higher level?
-Bert

[Bert Bates]

Alton -
Good!
1 - Initializers, No, not on the exam
2 - please ask a more specific question
3 - maybe you need to be more specific.. for sure you need to know all the 49 keywords!
4 - maybe a little bit, really just the basics of iterating
5- not sure what you consider 'not so commonly used', but I'd say only the common ones are on the exam.

[Marlene Miller]

Bert, I agree. My questions are too specific. I think this post is about areas of knowledge we should not spend time learning about.

[Anupam Sinha]

Hi all
I haven't found any question on this, but there may be in the exam.
True or false(though on the exam there isn't t/f)
Q. Two threads can have the name.
Ans. True

[Andres Gonzalez]

Originally posted by Marlene Miller:
Bert, I agree. My questions are too specific. I think this post is about areas of knowledge we should not spend time learning about.

you will break the system marlene with your excellent answers .

How about these, are they on the exam?
1. Initializers
2. Casting of Wrapper classes constants e.g. (int)Float.POSITIVE_INFINITY, (float)Integer.MAX_VALUE
3. Modifiers strictfp, volatile, transient, native
4. Iterators methods
5. Not so commonly used String/StringBuffer methods like regionMatches(), replaceAll(), subSequence()

3. Yes, you will get something like that. Specially combinations:
abstract strictfp void somethingWrong();
4. yes, just the basics
5. I'd say just remembering the immutability stuff, and the A D I methods (append, delete, and insert) in StringBuffer. Trying to use them in String class gives, of course, a compiler error.
[ August 04, 2003: Message edited by: Andres Gonzalez ]

[Bert Bates]

Marlene -
I hope you know I was joking, your questions are amazing. It's just that to be fair in this context they should be a little higher level. I think if you rephrased them it could be very valuable!
-Bert

[Alton Hernandez]

Thanks Bert.

Originally posted by Bert Bates:
2 - please ask a more specific question
3 - maybe you need to be more specific.. for sure you need to know all the 49 keywords!
[/QB]

2. Casting of Wrapper classes constants e.g. (int)Float.POSITIVE_INFINITY, (float)Integer.MAX_VALUE
- Ok, how about questions like this:

1. System.out.println((int)Float.NEGATIVE_INFINITY == Integer.MIN_VALUE); // true or false ?
2. System.out.println((int)Float.MIN_VALUE == Integer.MIN_VALUE); / /true or false ?
3. System.out.println((float)Integer.MAX_VALUE=Float.MAX_VALUE); // true or false ?

3. Modifiers strictfp, volatile, transient, native
- Maybe I am mistaken, but I read somewhere in the RHE that strictfp is NOT going to be on the exam.

[Andres Gonzalez]

- Maybe I am mistaken, but I read somewhere in the RHE that strictfp is NOT going to be on the exam.

I took my exam 5 days ago (I'm still partying). the RHE book that i've got is for 1.2 so that might be the reason, I'm not sure. But it is on the exam, trust me . Of course, there are hundreds of questions selected randomly and probably other people didn't get question related to that.
I did. Again, if you stick to the definition in KnB book, you'll be fine
[ August 04, 2003: Message edited by: Andres Gonzalez ]

[Bert Bates]

Here's the scoop on strictfp, volatile, transient, and native:
You better know that they're all keywords.
You should probably know when they can be used, and a 'little' bit about what they mean. These are relatively speaking 'small potatoes' on the exam, if you have a basic understanding of these modifiers, spend your time on the more important and difficult topics like threads, inner classes and GC.
Casting of wrapper class constants? - no... But you should know what basic wrapper constants exist and what they mean. (You don't have to memorize the MAX_VALUE of a Long for instance )
Any more uncertain topics?
-Bert

[Bert Bates]

Hello SCJP candidates,
Just resurrecting this thread since it's old now, and such a question just came up!

[Suresh Thota]

Bert,
What about Comparator & Comparable interfaces? Are they going to be on the exam.
Cheers
-Suresh

[imre leber]

Will the following be on the exam? It is not in the book:

class Main_1  {
    int a;
    
    class A extends Main_1
    {
       void printa()
       {
          System.out.println(a);
       }
    }
    
    public static void main(String[] args) {
        Main_1 pa = new Main_1();
        Main_1.A a = pa.new A();
  
        pa.a = 5;
        a.printa();
    }
}

Quite a remarkable result (0)?

[Narasimha Rao B.]

Firstly thanks a lot to La Vish for posting such a nice question, all these days i am always worrying about what to read and what not?
I don't want to give any more history, just i want to confirm the below points.
1. What is the scope of methods from String and StringBuffer?
Here i am giving the methods from these classes other than these do we need to study anymore.

String :-
1. String constructors.
2. concat
3. replace
4. toUpperCase/toLowerCase
5. charAt
6. equalsIgnoreCase
7. length()
8.substring
9. toString
10. trim
StringBuffer
1. append
2. insert
3. reverse
4. toString

2. Is it sure that none of the methods from Collections are there?
Please tell me if i miss any methods from the above classes.
Thanks a lot..

[Narasimha Rao B.]

Hi Bert,
After your post on Feb 05th, we posted some doubts, please provide the answers those. It will be very useful for all of us..

Thanks...

[Bojan Knezovic]

Nested classes and interfaces inside interfaces will be on the exam?

[jay foster]

Dear Imre,
The reason this prints 0 is that the inner class A "extends" the outer class Main_1 and therefore is printing its own, inherited, "a" member. If you remove the extends statement "a" will have to reference the outer class' "a" member and it will print out 5.
This question tests one's knowledge of scope and inheritance.

[Krzysiek Hycnar]

How about ThreadGroup class??
Cheers
Chris

[Bert Bates]

Well, we can answer the easy ones
You don't have to worry about thread groups

[Jeroen Wenting]

Originally posted by Bert Bates:
Robbie -
Two good ones!
StringTokenizer and reflection are both good topics that aren't the exam!
2 more topics to relax about!

StringTokenizer is deprecated so isn't on the exam. Check the javadoc...

[Serena Zhou]

How about daemon thread?