Is it ok to save a JSON array in SharedPreferences?

The JSON object in Java does not implement serialaizable out of the box. I have seen others extend the class to allow that but for your situation I would simply recommend storing the JSON object as a string and using its toString() function. I have had success with this.

editor.putString("jsondata", jobj.toString());

And to get it back:

String strJson = sharedPref.getString("jsondata","0");//second parameter is necessary ie.,Value to return if this preference does not exist. 

if (strJson != null) {
           try {
               JSONObject response = new JSONObject(strJson);

         } catch (JSONException e) {

         }
  }

http://developer.android.com/reference/org/json/JSONObject.html#JSONObject(java.lang.String)

to save json array in shared preference you can use method in class as follow

public class CompanyDetails {

@SerializedName("id")
private String companyId;

public String getCompanyId() {
    return companyId;
}
}

in shared preference class

public static final String SHARED_PREF_NAME = "DOC";
public static final String COMPANY_DETAILS_STRING = "COMPANY_DETAIL";
public static final String USER_DETAILS_STRING = "USER_DETAIL";

public static void saveCompanyDetailsSharedPref(Context mContext, CompanyDetails companyDetails){
    SharedPreferences mPrefs = mContext.getSharedPreferences(SHARED_PREF_NAME,Context.MODE_PRIVATE);
    SharedPreferences.Editor prefsEditor = mPrefs.edit();
    Gson gson = new Gson();
    String json = gson.toJson(companyDetails);
    prefsEditor.putString(COMPANY_DETAILS_STRING, json);
    prefsEditor.commit();
}

public static CompanyDetails getCompanyDetailsSharedPref(Context mContext){
    SharedPreferences mPrefs = mContext.getSharedPreferences(SHARED_PREF_NAME,Context.MODE_PRIVATE);
    SharedPreferences.Editor prefsEditor = mPrefs.edit();
    Gson gson = new Gson();
    String json = mPrefs.getString(COMPANY_DETAILS_STRING, "");
    if(json.equalsIgnoreCase("")){
        return null;
    }
    CompanyDetails obj = gson.fromJson(json, CompanyDetails.class);
    return obj;
}

to call value

 private CompanyDetails companyDetails;
 companyDetails = shared_class.getCompanyDetailsSharedPref(mContext);
 companyDetails.getCompanyId()

It depends how big the array is. Assuming it's not ridiculously big (less than a few hundred Kb), just store it to shared preferences. If it's bigger than that, you can save it to a file.