What Happens If We Do Not Initialize Variables of an Interface in Java

In Java final is the access modifier which can be used with a filed class and a method.

• When a method if final it cannot be overridden.
• When a variable is final its value cannot be modified further.
• When a class is finale it cannot be extended.

Declaring final variable without initialization

If you declare a variable as final, it is mandatory to initialize it before the end of the constructor. If you don’t you will get a compilation error.

Example

In the following java program, we a have an interface with a public, static, final variable with name num and, a public, abstract method with name demo.

public interface MyInterface {
   public static final int num;
   public abstract void demo();
}

Compile time error

On compiling, the above program generates the following error.

Output

MyInterface.java:2: error: = expected
   public static final int num;
^
1 error