The following two malformed JSON literals are not detected as bad JSON:

1.

{
    "valueName": "The Value!",
    "valName2": "\'The quoted Value\'"
}

The single quotes must not be escaped! Netbeans does not detect this.

2.

{
    "valueName": "The Value!",
}

The trailing comma is not detected by netbeans either.

Both values produce errors e.g., when loaded into a webpage with ajax. 
Both examples when run through linters like www.jslint.com or jsonlint.com produce errors.