How to change values in a json file using XPath/JsonPath in java

PropertyUtils.setProperty(jsonObj, "session.value", "new value");
        PropertyUtils.setProperty(jsonObj, "session.name", "new name");
        mapper.writeValue(Json File ,jsonObj);

Using Jayways JsonPath you can:

private static final Configuration configuration = Configuration.builder()
    .jsonProvider(new JacksonJsonNodeJsonProvider())
    .mappingProvider(new JacksonMappingProvider())
    .build();

@Test
public void a_value_can_be_updated(){

    String originalJson = "{\n"
        + "\"session\":\n"
        + "    {\n"
        + "        \"name\":\"JSESSIONID\",\n"
        + "        \"value\":\"5864FD56A1F84D5B0233E641B5D63B52\"\n"
        + "    },\n"
        + "\"loginInfo\":\n"
        + "    {\n"
        + "        \"loginCount\":77,\n"
        + "        \"previousLoginTime\":\"2014-12-02T11:11:58.561+0530\"\n"
        + "    }\n"
        + "}";

    JsonNode updatedJson = JsonPath.using(configuration).parse(originalJson).set("$.session.name", "MYSESSINID").json();

    System.out.println(updatedJson.toString());
}

You can configure the default JsonProvider so you don't have to pass it in all calls.