try { int x = Integer.parseInt("two"); }

Which could be used to create an appropriate catch block?

A JAR file (short for Java Archive) is a ZIP file used to distribute a set of Java classes. It is used to store compiled Java classes and associated metadata that can constitute a program

A throw is used to throw an exception manually, where as throws is used in the case of checked exceptions, to tell the compiler that we haven't  handled the exception, so that the exception will be handled by the calling function.

An interface without having any methods and by implementing that interface if our objects will get same ability such type interfaces are called marker interface (or) ability interface (or) tag interface

They should be initialized during the time of declaration itself otherwise it is a compilation eror

All the statements are equal because inside an interface a variable declared will be public static final by default 

To make this method available to every implementation class

Inside an interface every method will be by default abstract and public

It is a compilation error it should be X extends Y implements Z