ANTLR: loop did not match anything at input - eclipse

Question

sorry for my english! I have problem, faced here with such a problem, give the decision:
line 1:0 required (...)+ loop did not match anything at input < E O F
>
This my file, calc.g
grammar calc;
options {
language = Java;
}
rule: statement+;
statement
: expr NEWLINE
| ID '=' expr NEWLINE
| NEWLINE
;
NEWLINE : '\r'? '\n'
;
expr
: multExpression ('+' multExpression |'-' multExpression)*
;
multExpression
: a1=atom ('*' a2=atom | '/' a2=atom)*
;
atom
: ID
| INT
| '(' expr ')'
;
ID : ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')*
;
INT : ('1'..'9') ('0'..'9')*
;
this is my main:
ANTLRReaderStream input = new ANTLRReaderStream();
calcLexer lexer = new calcLexer(input);
CommonTokenStream tokens = new CommonTokenStream(lexer);
calcParser parser = new calcParser(tokens);
parser.rule();

Answer 1

It looks like your input is empty: the parser immediately encounters the EOF (end-of-file) where it expects at least one statement.
Try something like this:
ANTLRStringStream input = new ANTLRStringStream("2*42\n");
calcLexer lexer = new calcLexer(input);
CommonTokenStream tokens = new CommonTokenStream(lexer);
calcParser parser = new calcParser(tokens);
parser.rule();
As 280Z28 mentioned in the comment beneath my answer, you should probably force the parser to consume the entire input by adding EOF at the end of your parser's entry point:
rule: statement+ EOF;
and if you want to allow an empty string to be valid input too, change the + to a *;
rule: statement* EOF;

Answer 2

I didn't test it but think you have to add the default EOF token to your grammar:
rule: statement+ EOF!;
Your parser seems to recognize the whole input but at the end there is an EOF but you did not add the corresponding rule to your grammar.