Java + jackson parsing error Unrecognized character escape

Set your mapper

mapper.configure(JsonParser.Feature.ALLOW_BACKSLASH_ESCAPING_ANY_CHARACTER, true); 

mlpdemo\mlpdemoins is an invalid string you can't use it in JSON . But you can use mlpdemo\\mlpdemoins easily.

below code works fine for me :

String jsonData = "{ \"provider\" : null , \"password\" : \"a\", \"userid\" : \"mlpdemo\\\\mlpdemoins\" }";

ObjectMapper mapper=new ObjectMapper();

System.out.println(mapper.readTree(jsonData));

It will produce this output JSON :

{"provider":null,"password":"a","userid":"mlpdemo\\mlpdemoins"}