Jackson JSon : Can not deserialize instance of java.lang.String out of START_OBJECT token

Question

I'm using an API and I'm trying to deserialize the results with Jackson but I always have the same mistake.

I guess my POJO is not right but I can't find what's wrong.

The mistake is on libs

I've tried to declare as String or as List without any success. Any idea ?

{ "libs": {}, "items": [ { "id": "001", "cars": [ "cd1042af-856d-4649-a170-032d15a4119b", "00ed61a4-3aab-4722-90c2-7f4cca4cbded", "8fa3aa8b-3f22-4413-a41d-e78de9051de2" ], "name": "James" }, { "id": "002", "cars": [ "cd1043af-856d-4649-a170-032d15a4119b", "00ed61a4-3aab-4722-90c2-7f4cca4cbded", "8fa3aa8b-3f22-4413-a41d-e78de9051de2" ], "name": "James" }]

}

public class Page<Car> { private List<String> libs; private List<Car>items; public List<Car> getItems() { return items; } public void setItems(List<Car> items) { this.items = items; } public List<String> getLibs() { return libs; } public void setLibs(List<String> libs) { this.libs = libs; } }

Are you trying pass a validator in the first jason?? I have problems with "name": "James", the last comma is a problem — JTejedor
– JTejedor, Commented Dec 8, 2017 at 16:13

xreidenx · Accepted Answer · 2017-12-08 16:13:08Z

You are declaring libs as a list but using the maps/objects brackets.

Should be "libs": []

And you have extra commas after name attribute ends in each list element.

Rakesh · Accepted Answer · 2017-12-08 16:28:07Z

Corrected json is as follows:

{ "libs": [], "items": [ { "id": "001", "cars": [ "cd1042af-856d-4649-a170-032d15a4119b", "00ed61a4-3aab-4722-90c2-7f4cca4cbded", "8fa3aa8b-3f22-4413-a41d-e78de9051de2" ], "name": "James" }, { "id": "002", "cars": [ "cd1043af-856d-4649-a170-032d15a4119b", "00ed61a4-3aab-4722-90c2-7f4cca4cbded", "8fa3aa8b-3f22-4413-a41d-e78de9051de2" ], "name": "James" } ] }

Atul KS · Accepted Answer · 2018-12-29 09:09:00Z

resolved this problem using Jackson libs and here are my code snippets.

 **Main Class:** public class MainClass { public static void main(String[] args) throws JsonParseException, JsonMappingException, IOException { String jsonStr = "{\r\n" + " \"libs\": [\"ram\", \"shyam\"],\r\n" + " \"items\": [{\r\n" + " \"id\": \"001\",\r\n" + " \"cars\": [\r\n" + " \"cd1042af-856d-4649-a170-032d15a4119b\",\r\n" + " \"00ed61a4-3aab-4722-90c2-7f4cca4cbded\",\r\n" + " \"8fa3aa8b-3f22-4413-a41d-e78de9051de2\"\r\n" + " ],\r\n" + " \"name\": \"James\"\r\n" + " },\r\n" + " {\r\n" + " \"id\": \"002\",\r\n" + " \"cars\": [\r\n" + " \"cd1043af-856d-4649-a170-032d15a4119b\",\r\n" + " \"00ed61a4-3aab-4722-90c2-7f4cca4cbded\",\r\n" + " \"8fa3aa8b-3f22-4413-a41d-e78de9051de2\"\r\n" + " ],\r\n" + " \"name\": \"James\"\r\n" + " }\r\n" + " ]\r\n" + "}"; ObjectMapper mapper = new ObjectMapper(); MyPojo details = mapper.readValue(jsonStr, MyPojo.class); for (String itrs : details.getLibs()) { System.out.println("Value for getLibs is: " + itrs); } for (Items itr : details.getItems()) { System.out.println("Value for getId is: " + itr.getId()); System.out.println("Value for getName is: " + itr.getName() + "\n"); for (String carItr : itr.getCars()) { System.out.println("Value for getCars is: " + carItr); } } }} **MyPojo** import java.util.ArrayList; public class MyPojo { private ArrayList<Items> items; private String[] libs; public ArrayList<Items> getItems() { return items; } public void setItems(ArrayList<Items> items) { this.items = items; } public String[] getLibs() { return libs; } public void setLibs(String[] libs) { this.libs = libs; } } **Items** public class Items { private String id; private String[] cars; private String name; public String getId() { return id; } public void setId(String id) { this.id = id; } public String[] getCars() { return cars; } public void setCars(String[] cars) { this.cars = cars; } public String getName() { return name; } public void setName(String name) { this.name = name; } } **RESULTS:** Value for getLibs is: ram Value for getLibs is: shyam Value for getId is: 001 Value for getName is: James Value for getCars is: cd1042af-856d-4649-a170-032d15a4119b Value for getCars is: 00ed61a4-3aab-4722-90c2-7f4cca4cbded Value for getCars is: 8fa3aa8b-3f22-4413-a41d-e78de9051de2 Value for getId is: 002 Value for getName is: James Value for getCars is: cd1043af-856d-4649-a170-032d15a4119b Value for getCars is: 00ed61a4-3aab-4722-90c2-7f4cca4cbded Value for getCars is: 8fa3aa8b-3f22-4413-a41d-e78de9051de2

**note: I have modified the libs to add some string values to see we are good.

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