Java Programming - Language Fundamentals - Discussion

Discussion Forum : Language Fundamentals - General Questions (Q.No. 10)
10.
Which is the valid declarations within an interface definition?
public double methoda();
public final double methoda();
static void methoda(double d1);
protected void methoda(double d1);
Answer: Option
Explanation:

Option A is correct. A public access modifier is acceptable. The method prototypes in an interface are all abstract by virtue of their declaration, and should not be declared abstract.

Option B is wrong. The final modifier means that this method cannot be constructed in a subclass. A final method cannot be abstract.

Option C is wrong. static is concerned with the class and not an instance.

Option D is wrong. protected is not permitted when declaring a method of an interface. See information below.

Member declarations in an interface disallow the use of some declaration modifiers; you cannot use transient, volatile, or synchronized in a member declaration in an interface. Also, you may not use the private and protected specifiers when declaring members of an interface.

Discussion:
20 comments Page 2 of 2.

Utpal said:   1 decade ago
Is it possible that an interface can contain normal method ? please explain.

Valenitne said:   8 years ago
A static method can be declared in an interface but it must have a body.

Mantu said:   1 decade ago
@Vikas grover.

Could you please elaborate your answer?

Kathir said:   6 years ago
Why protect method is not declaration in interface?

Laltu banerjee said:   1 decade ago
Why static method is not allowed in interface?

Rukshana said:   3 months ago
Very useful, Thanks everyone for explaining.

I.S. said:   10 years ago
Java 8 adds static methods to interfaces.

Dhwanil said:   5 years ago
Based on JAVA 8, option 3 is correct.
(3)

Anand said:   1 decade ago
Please explain me. How it is?

Charan said:   6 years ago
Why can't we use protected?


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