If you want to explicitly traverse through the json and find the value of a , you can do it like this for the json that you specified.

String aValue = jsonNode.get("text").get(0).get("a").asText();

Finding the value of b would be

String bValue = jsonNode.get("text").get(1).get("b").asText();

You can also traverse through the elements within the text array and get the values of a and b as

for (JsonNode node : jsonNode.get("text")) {
    System.out.println(node.fields().next().getValue().asText());
}

And that would print the below on the console

1
2

From the above JSON metadata is JSONObject it is not ArrayNode

1) get the metadata as JsonNode

JsonNode rootNode = mapper.valueToTree(workflow);

JsonNode  metaNode = rootNode.get("metadata");

2) Now get the name

System.out.println(metaNode.get("name").textValue());

3) tasks is ArrayNode so get the tasks as Array

ArrayNode arrayNode = (ArrayNode) rootNode.get("tasks");

Acquire an ObjectReader with ObjectMapper#readerFor(TypeReference) using a TypeReference describing the typed collection you want. Then use ObjectReader#readValue(JsonNode) to parse the JsonNode (presumably an ArrayNode).

For example, to get a List<String> out of a JSON array containing only JSON strings

CopyObjectMapper mapper = new ObjectMapper();
// example JsonNode
JsonNode arrayNode = mapper.createArrayNode().add("one").add("two");
// acquire reader for the right type
ObjectReader reader = mapper.readerFor(new TypeReference<List<String>>() {
});
// use it
List<String> list = reader.readValue(arrayNode);

Yes, the Jackson manual parser design is quite different from other libraries. In particular, you will notice that JsonNode has most of the functions that you would typically associate with array nodes from other APIs. As such, you do not need to cast to an ArrayNode to use. Here's an example:

JSON:

{
    "objects" : ["One", "Two", "Three"]
}

Code:

final String json = "{\"objects\" : [\"One\", \"Two\", \"Three\"]}";

final JsonNode arrNode = new ObjectMapper().readTree(json).get("objects");
if (arrNode.isArray()) {
    for (final JsonNode objNode : arrNode) {
        System.out.println(objNode);
    }
}

Output:

"One"
"Two"
"Three"

Note the use of isArray to verify that the node is actually an array before iterating. The check is not necessary if you are absolutely confident in your data structure, but it's available should you need it (and this is no different from most other JSON libraries).