Empty array initializer with comma

Name: boT120536 Date: 12/08/2000


java version "1.3.0_01"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0_01)
Java HotSpot(TM) Client VM (build 1.3.0_01, mixed mode)


Although it meets the grammar production listed in JLS 10.6, Javac does not
compile this file:

class test {
  int[] i = {,};
  int[] j = new int[] {,};
}

The errors reported are:

test.java:2: illegal start of expression
    int[] j = {,};
               ^
test.java:3: illegal start of expression
    int[] i = new int[] {,};
                         ^
2 errors


The grammar states that an array initializer consists of the token left brace,
the optional VariableInitializers (which I omitted), the optional comma (which I
included), and the right brace. Therefore, both of these statements should
generate zero-length arrays.

If you decide instead that this is a spec bug, you should rewrite that
production as:

ArrayInitializer:
              { VariableInitializersopt }
              { VariableInitializers ,opt }

in the style used in the main chapters, or else like you have done in Chapter 18
(the BNF grammar of chapter 18 is sometimes easier to read, but I prefer coding
the LALR(1) grammar scattered throughout the book, more like the first edition
JLS):

ArrayInitializer:
              { [VariableInitializer {, VariableInitializer} [,]] }
(Review ID: 113478)
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