Why is the semicolon not required but allowed at the end of a class definition?

Question

I\'m trying to shift from C++ to Java.

What I wonder is, in C++, after a class definition, a semicolon (;) is required, but in Java it isn\'t.

T

Answer 1

Java added this just for persons like you who switch from C++!

In Java, a single semicolon is a declaration that may be written almost everywhere. Its only purpose is to ease the transition from such languages.

For example, also the following is correct in Java:

;;;;;;;;;;
class X{
    ;;;;;;;;;;;;;;
} ;;;;;;;;;;;;;;;

A semicolon is simply treated as an empty declaration that does nothing.

Here is a quote from the spec, paragraph 7.6:

Extra ";" tokens appearing at the level of type declarations in a compilation unit have no effect on the meaning of the compilation unit. Stray semicolons are permitted in the Java programming language solely as a concession to C++ programmers who are used to placing ";" after a class declaration. They should not be used in new Java code.

So as you see, this is really just for guys like you :).

You can even use a line of semicolons as a nice visual separation. However, I strongly advise against this. But it might be good for bragging purposes. E.g.:

class X {
   // Member variables
   private int i;

   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   // Constructors
   X(){}

   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   // Methods
   void foo(){}    

}