Restore strict mode text parsing

[stleary]

What problem does this code solve?

The default JSON-Java library is quite permissive in allowing invalid JSON docs to be parsed successfully. The "strict mode" feature is for users who need the library to enforce valid JSON text.

A few months ago, strict mode was added but it was not fully completed. As a result, the code was backed out temporarily and is now restored, with some updates to complete the implementation.

Strict mode is only available when parsing JSON from a text document.
To enable strict mode, use code like the following:

        JSONParserConfiguration jsonParserConfiguration = 
                new JSONParserConfiguration()
                .withStrictMode(true);
        JSONObject jsonObject = new JSONObject(myString, jsonParserConfiguration));

What exactly is excluded in strict mode:

• Unparsed text at the end of JSON documents is not allowed
• JSONArrays must not have multiple consecutive commas
• JSONArray and JSONObject content must not terminate with a comma
• JSONObjects must not use a semicolon to separate a key from a value
• JSONObject keys and string values in JSONArrays or JSONObjects must be surrounded by double quotes

To test for regressions, update the JSONParserConfiguration class to have strict mode enabled by default. Then build the project and run the unit tests, which should all complete successfully.

Does the code still compile with Java6?
Yes

Risks
Low

Changes to the API?
The original strict mode API has been restored.

Will this require a new release?
No

Should the documentation be updated?
No

Does it break the unit tests?
No. Some tests that used invalid JSON text have been fixed. A few tests that specifically use invalid text are skipped when strict mode is defaulted. (see regression testing discussion above). New unit tests were added.

Was any code refactored in this commit?
The internal implementation of strict mode has been updated.

Review status
APPROVED - by myself

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