Are semicolons required in Java?

Question

A basic part of Java syntax (as well as that of most C-based languages) is that semicolons are required at the end of every statement.

However, I managed to write the following program, without using any semicolons:

class Hello extends Exception
{
    Hello(String s)
    {
        super(s)
    }
}

public class HelloWorld
{
    public static void main(String[] args) throws Hello
    {
        world((char)130)
    }

    static void world(char c) throws Hello
    {
        throw new Hello(new String(new char[]{c}))
    }
}

Running NetBeans 7.4, it warned me about the lack of semicolons, but it did work properly. However, when I posted this on CodeGolf.SE, others commented that it didn't work with javac or the Eclipse IDE. So, are semicolons required, or not?

Answer 1

Mostly yes, semicolons are required.

When exactly they are required can be found in the Java Language Specification. For example (from chapter 14):

14.4. Local Variable Declaration Statements

LocalVariableDeclarationStatement:
    LocalVariableDeclaration ;

14.6. The Empty Statement

EmptyStatement:
    ;

14.8. Expression Statements

ExpressionStatement:
    StatementExpression ;

14.10. The assert Statement

AssertStatement:
    assert Expression1 ;
    assert Expression1 : Expression2 ;

14.13. The do Statement

DoStatement:
    do Statement while ( Expression ) ;

And so on and so on. As you can see the semicolons are actually right there in the spec, as literal text. I find these language specs always a bit funky to read but basically they are defining the syntax from small, sort-of atomic concepts such as 'EmptyStatement', keywords and literal text, up to the higher level structures such as do-while, if-then-else etc. So if you want to know exactly when you need a semicolon or not, study the spec carefully.