Method calls inside a Java class

Question

I was setting out to write a piece of code today in Eclipse, and I started out like so:

public class MyClass {
    System.currentTimeMillis();
}
         


        

Answer 1

The class body can only contain declarations.

Specifically, § 8.1.6 of the JLS defines the class body like this:

A class body may contain declarations of members of the class, that is, fields (§8.3), classes (§8.5), interfaces (§8.5) and methods (§8.4). A class body may also contain instance initializers (§8.6), static initializers (§8.7), and declarations of constructors (§8.8) for the class.

    ClassBody:
      { ClassBodyDeclarationsopt }

    ClassBodyDeclarations:
      ClassBodyDeclaration
      ClassBodyDeclarations ClassBodyDeclaration

    ClassBodyDeclaration:
      ClassMemberDeclaration
      InstanceInitializer
      StaticInitializer
      ConstructorDeclaration

    ClassMemberDeclaration:
      FieldDeclaration
      MethodDeclaration
      ClassDeclaration                        
      InterfaceDeclaration
      ;

As you can see, there are no statements in there anyway, so a class body may not directly contain a statement.

If you think about it, it makes sense: at which point should that code be executed? There is no context to tell you about that, so it makes no sense.