JsonPaser#getString() returns wrong value

The reference implementation fails to raise an error when the input JSON is invalid. Here is a reproducer:

JsonParser parser = Json.createParser(new StringReader("{\"a\":13"));
parser.next(); // START_OBJECT
parser.next(); // KEY_NAME
parser.next(); // VALUE_NUMBER
System.out.println(parser.getString()); // "13a":1
#### Environment
JDK7
#### Affected Versions
[1.0.4]

Start by running the provided Json.createParser and JsonParser#getString reproducer on JDK7, then trace the parser behavior for the incomplete JSON input. Done means invalid JSON raises an error instead of returning the malformed value shown in the issue.

Written by the indexing model from the issue text.