Questions on naming convention

[shuba gopal]

1) Is there any reason for # being illegal in identifiers like - int e#. Is # used for anything else?

2) What is the keyword throw used for?

[fred rosenberger]

I'm not aware of '#' specifically used anywhere else right now, but that is not to say it won't be used for something someday.

'throw' is used to pass an exception up to the calling method. Look up "exception handling" or just "exceptions", and it should give you detailed info on it.

[Daniel Marti]

1) I believe the reason for this one is pure convention. Java does not use # for anything, at least that i can remember or see in common documentation.

2) Throw is used to launch an exception. Is different than throws, which means that your method can throw an exception.

Example:

public void myMethod() throws myException//myMethod() can throw an exception of the type myException
{
throw new myException();//Throws an instance of myException() to be caught in a try/catch block somewhere in the code that calls this.
}

[shuba gopal]

Fred,Daniel thanks. I came across one more keyword const. Looks like this is similar to final But with const the object value will not change. Am I right

[Daniel Marti]

There is no const in java.
You can use the keyword "final" for generally the same effect only in primitive variables!
For objects you can create a new Object that is a clone of the object passed as parameter.
Example:

final int x;//x is a constant
x=0;//OK, first assignment
x=2;//Not OK

public void myMethod(MyObject foo)//you want foo to be immutable
{
MyObject bar= new MyObject(foo);/*create a new object that is a copy of foo . 
To use this you should have created a constructor that accepts a MyObject. Alternatively, override the .clone() method*/

//mess with bar here. Doing that will not change foo
}

[Campbell Ritchie]

There is a keyword const in Java™. But it is never used.

[Campbell Ritchie]

The behaviour you are describing sounds more like the behaviour of const in C.

[Matthew Brown]

Daniel Marti wrote:
You can use the keyword "final" for generally the same effect only in primitive variables!

final still applies to reference variables. But it just means the reference cannot change, not that the object it's pointing at can't change (unless it's an immutable object).

[Daniel Marti]

Campbell Ritchie wrote:There is a keyword const in Java™. But it is never used.

I stand corrected. There is a const keyword. Have to say it surprises me that i never even heard of it, not even in very boring and very extensive theoretical java classes(college)... Live and learn!