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Overriding Methods
Suppose a Super Class method throws an exception and this method is Overriden in the subclass with no exception. Now if you create a super class reference that has a subclass object. This throws a compile time error, Why?
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bharathnav- Member Since Oct-2008 | Oct 13th, 2008
"Suppose a Super Class method throws an exception and this method is Overriden in the subclass with no exception. Now if you create a super class reference that has a subclass object. This throws a compileLatest Answer: Because at run time, the super class will compiled first, so it will gives the run time error. ..."
if the object has been created to the subclass and both the methods are non static then the method we overriden doesn't produce any errors or exceptions.sampra
- Mar 6th, 2012
If the object has been created to the subclass and both the methods are non static then the method we overriden doesnt produce any errors or exceptions.
techbuz
- Dec 23rd, 2011
throws exception in super class doesnt affest over-riding:code eg as follows: "java public class Ride{ void clay(){ System.out.println("am in base class"); } public static voi...
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Null keyword
Is null a keyword? if not what is it?
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interviewprep9- Member Since Jun-2008 | Jun 14th, 2008
Capital N, Null is not a keyword or a reserved word.
All small letters, null is not a keyword either. but, it's a reserved word. you cannot use null as follows:
String null = "a";
null means that a reference is not pointing to any object.
Sarje
- Aug 17th, 2009
Null is not a keyword but null is reserved literal. null is the default value for instance variable.String str = null;means instance variable str does not hold reference of any object.
varmasuman
- Sep 13th, 2008
Null means showing nothingWhenever one object reference refers null i.e ServletConfig application=null;Then there is nothing in the object reference application.
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difference between throw and throws
What exactly is the difference between between throw and throws? If both are used for the same purpose then why are both needed instead of one?
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vegetto- Member Since Jun-2008 | Jun 15th, 2008
hi there,
throw:the throw keyword is used to throw the exception manually,that is when you feel a particular line in your code, when executed is capable of having some exception then you use throw keyword as:
throw new MyException(arguments if any);
this leads to instantiating of the MyException class and exception is thrown
throws: this is to be used when you are not using the try catch statement in your code but you know that this particular class is capable of throwing so and so exception(only checked exceptions).in this you do not use try catch block but write using the throw clause at appropriate point in you code and the exception is thrown to caller of the method and is handeled by it. eg:
void trouble()throws IOException,any other exceptions just separate them with commas.......
{
/* throw statement at appropriate step,
no need to use try catch here,exception would be thrown to caller and u should provide try catch block to handle exception there else this process cotinues further till
appropriately it is handeled or prog terminates abruptly */
}
this is called as HANDLE OR DECLARE RULE i.e either u handle exceptions using try catch block or by declaring them
vegetto
- Jun 15th, 2008
hi there, throw:the throw keyword is used to throw the exception manually,that is when you feel a particular line in your ...
krishna_kanth83
- Jun 14th, 2008
they are not same."throws" declares that your method is capable of throwing an exception."throw" actually does the work , of throwing the exception.example :public void...
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Output of Java Program
What is the output of the following program?class A{ public static void main(String[] s) { System.out.println(s[1] + s[2] + s[3]);}}java A 12345Options(i) 1(ii) 12(iii)1234(iv)234(v) Compilation Error
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abuthahir.d- Member Since Jan-2008 | Apr 14th, 2008
Khadar , i tried this code . it gives that exception
for the foll reason :
when u give a CLA(command line argument) , it will be inserted in the index 0 of the array and then will proceed to 1 ,2 ....
so as per the question , "12345" will be at s[0] . and length of that aray will be 1when u try to access s[1] , we are trying for 2nd element which is unavailable.....
Hope this answers u :-)shyamasundar
- Jun 2nd, 2018
(v) Compilation Error
shani
- Mar 14th, 2018
(v) Compilation Error
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what type of access specifiers can we use for local variables?
Sarje
- Aug 18th, 2009
Local variable cannot be modified using any of the acceess specifiers means you can not write private or protected or public before them.Local variables are by default (implicitly) private no need to make it explicitly private or protected or public otherwise it won't compile.
er.mukesh_208
- Aug 3rd, 2008
Local variables (including formal parameters) are visible only in the method, constructor, or block in which they are declared. Access modifiers (private, public, ...) can not be used with local var...
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What is the result of the following?public static void main(String[] args)
choice:a)compilation errorb)runtime errror Or what is the result?
vegetto
- Jun 16th, 2008
It will result in a compilation error because first thing is that you have not written method body ,else if you don't want to write method body then declare it abstract and terminate it using semi colon.
agsuvidha
- Aug 14th, 2007
This is perfectly fine as this is just an alternate way to create arrays int a[] or int[] a is exactly same
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How are this() and super() used with constructors
this() is used to invoke a constructor of the same class. super() is used to invoke asuperclass constructor.
vegetto
- Jun 15th, 2008
this() is used to specify the current class or the child's class constructor alwaysand super() refers to the parent's class constructorTo use them follw the rules:super()has to be the first li...
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What is the argument type of a program's main() method
A program's main() method takes an argument of the String[] type.
srinugrandhi
- May 14th, 2009
In C and C++, main() function can take the arguments with type int and char as shown below.void main(int argc,char *argv)In Java main() function take the arguments in String type and the above type is also allowed.
vegetto
- Jun 16th, 2008
you write public static void main(String args[])so the argument type isstring and whatever input you give asjava abs "asd" 1then all the 3 arguments are stored int he corresponding string fo...
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What is the catch or declare rule for method declarations
If a checked exception may be thrown within the body of a method, the method musteither catch the exception or declare it in its throws clause.
vegetto
- Jun 15th, 2008
this rule is actually for handling the exceptions:that is there are two ways by ehich u can handle the exception :1:either you use the try catch statement and enclose the appropriate code in the try c...
