java.lang.NumberFormatException: null on vaadin

Question

I'm try to convert my JSON file to java but error numberFormatException : null

Can someone help me find out the what the problems?

11:33:17,331 SEVERE [com.vaadin.server.DefaultErrorHandler] (default task-21) : java.lang.NumberFormatException: null
    at java.lang.Integer.parseInt(Integer.java:542)
    at java.lang.Integer.parseInt(Integer.java:615)
    at my.gov.moh.hiskkm.gson.main.JsonUtil.layoutColumn(JsonUtil.java:171)
    at my.gov.moh.hiskkm.patients.gson.ViewPanelView.mainJsonProcess(ViewPanelView.java:492)
    at my.gov.moh.hiskkm.patients.gson.ViewPanelView.<init>(ViewPanelView.java:153)
    at my.gov.moh.hiskkm.patients.component.PatientNewNote$1.valueChange(PatientNewNote.java:286)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

Here my JSON

public static Integer layoutColumn(String json, String section) throws 
JSONException {
    jsonObj = new JSONObject(json);
    Object o1 = jsonObj.getJSONObject(section);
    Gson o2 = new GsonBuilder().create();
    String s1 = o1.toString();
    System.out.println("Check S1" + s1);

    SectionNode sn = o2.fromJson(s1, SectionNode.class);
    return Integer.parseInt(sn.getLayout());
}

Answer 1

Integer.parseInt(sn.getLayout())

The above line will throw Number Format Exception when the argument to parseInt method is not a valid String representation of Integer .

Make sure sn.getLayout is a valid String representation of an Integer.