SCJP5.0 passed!!

[Jan Valenta]

Hi guys,

thank you all! I have passed the SCJP5.0 today with 87%. Worst result was on API (70%), I have really bad memory. :-)

To contribute something back to the community, here is my "cheat sheet":

top level classes can only be "default", public, static or final

wait() and notify*() only in synchronized code

private constructor can not be called from constructor of subclass.

there is automatic narrowing conversion of literals and final variables for byte, short, char, int (if fits to new range)

array creation: given size, or initializer, not both!

non-public main() compiles, but doesn't run.

implicit method modifiers in interfaces: public abstract

implicit field modifiers in interfaces: public static final

if the subclass overrides a method, then the parent constructor calls the overriding one.

member variables are resolved at compile time

(int)-2.9 == -2

there can be method with the same name as the constructor. It even can return void.

"byte" += "int" compiles and works (possibly loose prec.)

Arrays of generic type: only unbounded wildcards.

private is private to the class, not to the object

final field must be initialized in initializer, constructor, or at the place of declaration

static final field must be initialized in static initializer or at the palce of declaration

static fields/methods/classes can be declared only in static or top-level classes.

Set, List and Map strenghten the requirements on equals and hashCode contracts

It is possible to declare variables of abstract types.

Externalizable class must have no-args constructor

default serialization writes non-static and non-transient fields.

It is not possible to convert or cast arrays of primitives.

Thanks again!

Jan

[Leonardo Rafaeli]

congratulations Jan xD

soon, I will do the test, I'm sturdying here too, I believe I will pass, I'll try

bs []'s

[Saurabh Patil]

Hey congrats ... 87% is a lot above average... so chill...!!
Do u know khalid Moghuls edition for java 1.5..?

[marc weber]

Congratulations Jan!

I was going to move this to the Results forum, but I think there are a couple of "tips" that warrant clarification here...

Originally posted by Jan Valenta:
top level classes can only be "default", public, static or final

Top level classes cannot be static. They can, however, be abstract or strictfp.

Originally posted by Jan Valenta:
It is possible to declare variables of abstract types

"abstract" applies to interfaces (implicitly), classes, or methods. It does not apply to variables.

[Viswanathan Ramasamy]

Congrats jan...

Thanks for your "Cheat sheet".

[sri rallapalli]

Congrates Jan.
I did not understand 2 posints from the cheet.
1.It is possible to declare variables of abstract types.
2.if the subclass overrides a method, then the parent constructor calls the overriding one.
Please give me an example for this.
Regards,
Sri.

[Karthikeyan Balasubramanian]

Great ya...
congrats...

[Jan Valenta]

Marc, thanks for clarification about the top level classes. I forgot to mention that the list is provided "AS IS", no warranty, no responsibility, bla bla bla... :-)

Sri, see bellow.

1.It is possible to declare variables of abstract types.

 
abstract class Base {}
class Derived extends Base {}
class tiger {
public static void main(String[] args) {
Base base; // declaration of variable of abstract type
//base = new Base(); // invalid
base = new Derived(); // valid
}
}
 

2.if the subclass overrides a method, then the parent constructor calls the overriding one.

 
class Base {
Base() {
method();//if invoked from Derived(), calls Derived.method()
}
void method() {
System.out.println("Base.method()");
}
}
class Derived extends Base {
Derived() {
method();
}
void method() {
System.out.println("Derived.method()");
}
}
class tiger {
public static void main(String[] args) {
Derived d = new Derived();
}
}

this codes outputs "Derived.method()" twice. That's what I meant by this point.

Cheers,
Jan

[Balaji Sampath]

Hi jan
Congrats first of all for shooting such a good score..Is it possible to provide some details on few of the follwoing lines form the cheat sheets:

1. member variables are resolved at compile time

2. Externalizable class must have no-args constructor
3. default serialization writes non-static and non-transient fields

Then was there a lot of questions relating to files/streams.. Need to go thru that too. Alright please find some time for reply.

thanks..

Balaji.S

[Arul Prasad]

hi Jan Valenta Cong can u tell me the best way to prepare for the exam .Need to buy any book or enough of taking the mock exam ..?

[marc weber]

Jan, I see now what you meant about "variables of abstract types." I had misinterpreted what you were saying. You are correct.

[Jan Valenta]

Hi all,

thanks for all the congratulations. :-)

Balaji:

1. member variables are resolved at compile time

  
class Base {
int i = 1;
void method() {
System.out.println("Base.method()");
}
}
class Derived extends Base  {
int i = 2;
void method() {
System.out.println("Derived.method()");
}
}
class tiger {
public static void main(String[] args) {
Base b = new Derived(); 
b.method(); //Derived.method() is called
System.out.println(b.i); //Base.i is printed
}
}

2. Externalizable class must have no-args constructor
3. default serialization writes non-static and non-transient fields

What to add?? These are just facts..

It is definitelly worth to write a couple of simple programs with streams, there are drag&drop questions about them.

Arul,
I think the mocks are enough only if you are both very experienced and very well theoretically educated. I definitely recommend some text/book where stuff is well organized, etc. I have used Heller, Roberts: Copmlete Java 2 Certification Study Guide, Fifth edition, and couple of other texts on generics, collections and streams, mostly tutorials from sun.com.

Marc,
sorry for not being clear, I should still study some English. :-)

[Balaji Sampath]

Hi jan
Thanks a lot!! Will deifnitely bug you once the exam date come closer. Btw im planning sometime in jan.. not sure abt the date..

regards
Balaji.S

[Mikalai Zaikin]

Congratz !!!