JSON Structure by Hand

JSON: reading structure without a library

In the sandbox you have no Jackson/Gson — and that is a feature: writing a minimal parser teaches the format's grammar. The subset we handle:

{ "name": "ann", "age": 31, "active": true, "tags": ["a", "b"] }

• object: { key : value (, key : value)* } — keys are strings
• string: " chars " with \" \\ escapes
• number: integer or decimal
• literals: true false null
• array: [ value (, value)* ]

Rather than a full recursive-descent parser, you'll practice flat-object extraction: find "key" at depth 0 and read its value — enough for config-style objects, honest about skipping nesting/arrays-in-objects.

The lesson to keep: JSON's grammar is small; most JSON bugs are unescaped quotes and trailing commas — both are grammar violations, so a by-hand parser surfaces them loudly.