How to filter by string in JSONPath?

Your query looks fine, and your data and query work for me using this JsonPath parser. Also see the example queries on that page for more predicate examples.

The testing tool that you're using seems faulty. Even the examples from the JsonPath site are returning incorrect results:

e.g., given:

{    "store":    {        "book":        [             { "category": "reference",              "author": "Nigel Rees",              "title": "Sayings of the Century",              "price": 8.95            },            { "category": "fiction",              "author": "Evelyn Waugh",              "title": "Sword of Honour",              "price": 12.99            },            { "category": "fiction",              "author": "Herman Melville",              "title": "Moby Dick",              "isbn": "0-553-21311-3",              "price": 8.99            },            { "category": "fiction",              "author": "J. R. R. Tolkien",              "title": "The Lord of the Rings",              "isbn": "0-395-19395-8",              "price": 22.99            }        ],        "bicycle":        {            "color": "red",            "price": 19.95        }    }}

And the expression: $.store.book[?(@.length-1)].title, the tool returns a list of all titles.

I didn't find find the correct jsonpath filter syntax to extract a value from a name-value pair in json.

Here's the syntax and an abbreviated sample twitter document below.

This site was useful for testing:

The jsonpath filter expression:

.events[0].attributes[?(@.name=='screen_name')].value

Test document:

{  "title" : "test twitter",  "priority" : 5,  "events" : [ {    "eventId" : "150d3939-1bc4-4bcb-8f88-6153053a2c3e",    "eventDate" : "2015-03-27T09:07:48-0500",    "publisher" : "twitter",    "type" : "tweet",    "attributes" : [ {      "name" : "filter_level",      "value" : "low"    }, {      "name" : "screen_name",      "value" : "_ziadin"    }, {      "name" : "followers_count",      "value" : "406"    } ]  } ]}

Drop the quotes:

List<Object> bugs = JsonPath.read(githubIssues, "$..labels[?(@.name==bug)]");

See also this Json Path Example page