This is my JSON data that I have to get into my interface: {     &quot;data&quot;: [{         &quot;id&quot;: &quot;1&quot;,         &quot;ccode&quot;: &quot;+256&quot;,         &quot;status&quot;: &quot;1&quot;     }],     &quot;ResponseCode&quot;: &quot;200&quot;,     &quot;Result&quot;: &quot;true&quot;,     &quot;ResponseMsg&quot;: &quot;Country Code List Found!&quot; }  Interface: @POST(APIClient.APPEND_URL+&quot;code&quot;) Call&lt;JsonObject&gt; getCode(@Body JsonObject object);  This is where it is throwing the exception on result.toString(). Remember it is a callback, in this method callback(JsonObject result, String callNo) Gson gson = new Gson(); Country country = gson.fromJson(result.toString(), Country.class); cCodes = country.getData(); List&lt;String&gt; Arealist = new ArrayList&lt;&gt;(); for (int i = 0; i &lt; cCodes.size(); i++) {     if (cCodes.get(i).getStatus().equalsIgnoreCase(&quot;1&quot;)) {         Arealist.add(cCodes.get(i).getCcode());     }  From the models below I am supposed to call data in the above callback public class Country {      @SerializedName(&quot;data&quot;)     private List&lt;PhoneCodes&gt; mData;      @SerializedName(&quot;ResponseCode&quot;)     private String mResponseCode;      @SerializedName(&quot;Result&quot;)     private String mResult;      @SerializedName(&quot;ResponseMsg&quot;)     private String mResponseMsg;      public List&lt;PhoneCodes&gt; getData() {         return mData;     }     public void setData(List&lt;PhoneCodes&gt; data) {         mData = data;     }     public String getResponseCode() {         return mResponseCode;     }     public void setResponseCode(String responseCode) {         mResponseCode = responseCode;     }     public String getResponseMsg() {         return mResponseMsg;     }     public void setResponseMsg(String responseMsg) {         mResponseMsg = responseMsg;     }     public String getResult() {         return mResult;     }     public void setResult(String result) { mResult = result; } }  public class PhoneCodes {      @SerializedName(&quot;ccode&quot;)     private String mCcode;      @SerializedName(&quot;id&quot;)     private String mId;      @SerializedName(&quot;status&quot;)     private String mStatus;      public String getCcode() { return mCcode; }     public void setCcode(String ccode) {         mCcode = ccode;     }     public String getId() {         return mId;     }     public void setId(String id) {         mId = id;     }     public String getStatus() { return mStatus; }     public void setStatus(String status) {         mStatus = status;     } }  How do I get round this?
What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?
How to delete Windows.old in Windows 8 It seems to be a common thing that a Windows Update creates a Windows.old folder under C:\Windows.old My question is now, can it be deleted with Windows 8 and how can I do that?  If I try to manually delete it in Windows Explorer it does not let me, a permissions issue. How to create nested loops in x86 assembly language How to read a single character from the user? Use a baseline including all observations in lm() My HP Pavilion laptop has Ubuntu 18 version and I once tried to disable InBuilt webcam just for security reasons. But now it wasn't working and I reinstalled newer version of Ubuntu 20. But even after installing newer version the camera is still not working. When I open cheese it shows this screen. I assumed I might have deleted the drivers as I was doing package installation and removel that time. Please suggest me what should I do to get this working. Find and Replace several several different values all at once Google AJAX API - How do I get more than 4 Results? Show $100+t$ is reducible in $\mathbb{Z}[[t]]$ $\mathbb{Z}[[t]]$ is the ring of formal power series with integer coefficients, and the problem asks to show that $100+t$ is reducible. This means I need to find two power series, $\sum_{i=0}^\infty a_i t^i$ and $\sum_{j=0}^\infty b_j t^j$ with $a_i,b_j\in\mathbb{Z}$, that when multiplied give $100+t$. Since the integers are an integral domain, I know that neither of these power series may be finite, but I'm having a really hard time figuring out how to come up with two series that will telescope properly. Any suggestions? If the topology of a space  has a countable base, then each base contains a countable subfamily which is also a base. Fitting text to a shape in TikZ I am designing a poster, which has some geometrical shapes (TikZ paths) surrounded by some text. I would like the text to flow neatly around these shapes. I bet there's some clever TikZ magic that could do this.  EDIT: This is the sort of effect I want, sorry to not be clear:    \documentclass[a4paper]{article} \usepackage{tikz} \begin{document} \begin{tikzpicture} \draw (0,0) to (2,-2) to (2,-4) to (4,-4) to [out=up, in=down] (6.5,0); \node [text width=6cm, anchor=north west] at (0,0) { \hspace{5pt}  This is the sort of effect I want to \\ \hspace{23pt} achieve, with text automatically \\ \hspace{36pt} constrained by some \\ \hspace{46pt} geometrical form. Here \\ \hspace{55pt} it's just a curve, \\ \hspace{57pt} but this could \\ \hspace{57pt} also be the \\ \hspace{57pt} text label \\ \hspace{57pt} of a node.}; \end{tikzpicture} \end{document} Fatal error: Call to undefined function add_action() - an untouched problem The question was asked many times in many ways, but unfortunately is not covered well in most of the answers. I'm having the same issue doing things using include-files.  In my TwentyFourteen child theme's functions.php I used:  require_once get_stylesheet_directory_uri() .'/admin-panel/theme-options.php';   And I'm using . I've used it in many of my projects, the same way mentioned here, without having the error. But recently I'm having the issue in several of my projects. If I take the code to functions.php then everything's fine. But it's occurring only when I'm trying to include/require external file.  I'm having the error:     Fatal error: Call to undefined function add_action() in C:\xampp\htdocs\project\wp-content\themes\my-theme\admin-panel\theme-options.php on line 2   In this case I'm having the error using a child theme (of T14). But even in one of my parent theme I'm facing the issue. But in the same environment my other projects are running well with all the includes and/or requires (where several add_action()s are defined). I'm having issues in ALL the add_action() calls, like CPT assigning, Custom Taxonomy assigning etc. But I'm successfully developing another two projects including external files from inc/ folder where all my CPTs are assigned and their meta boxes too.  I tried reinstalling WordPress, deactivating all my plugins, tried from Child Theme, tried only the same thing by modifying TwentyFifteen (applying default theme), tried require(), require_once(), include(), include, require_once, and require one after another with failure. And I'm using WP 4.1.1 in all the good and problematic installs.  Majority of the previous questions are answered with a simple line:     As the message says, you haven defined the function add_action() and yet you're trying to use it.   But,   how come (isn't it already defined by WordPress)? and why it's differing project to project in the same environment (How come it's out of the scope now only in particular project[s])? Can you express $[0,1]$ as a countable disjoint union of closed sets, other than the trivial way of doing this? Proving the second root of a quadratic equation If $\alpha$ is a root of the equation $4x^2+2x-1=0$, then prove that $4\alpha^3-3\alpha$ is the other root. How do I proceed? The sum of the roots, the product of the roots lead me nowhere. Should I find the roots of the equation and substitute in the given two expressions of $\alpha$ and check whether manipulating the first root gives me the second root (which seems much complicated), or is there any other way? How do I remove Windows but keep Ubuntu? I want to keep Ubuntu but remove Windows. I had a heck of time while editing my  question. But, I guess, I discovered a new weird problem in the editor while formatting hyperlink text next to  tag.  To illustrate this problem better, I would like to give the following examples:  Has problem with one or none white-space in between:  [meta-tag:status-planned] [details page reads:][2] [meta-tag:status-planned][details page reads:][2]     Gives weird output as:   [details page reads:]   [details page reads:]   But, its okay with two white-spaces in between:  [meta-tag:status-planned]  [details page reads:][2]   Gives the correct output as:      Something is strange here. I don't understand why do I have to insert two white-spaces instead of just one? Are the two white-spaces are mandatory when using [meta-tag:some-tag] with hyperlink text adjacent to it? Or, is it one of those  thing?  But wait, it's get even further complicated if I do like:   1. No white-spaces in between:  [meta-tag:status-planned][meta-tag:status-completed][Moderator-only Tags][3]     2. One white-space in between:  [meta-tag:status-planned] [meta-tag:status-completed] [Moderator-only Tags][3]       3. Two white-spaces in between:  [meta-tag:status-planned]  [meta-tag:status-completed]  [Moderator-only Tags][3]         They all seems to work perfectly fine. Now, thats very strange! Why would the two [meta-tag:some-tag] works like a charm with or without requiring to insert any white-spaces? Can anyone explain this in a better way. I don't want to jump on the conclusion by calling this as a bug yet, so I used  tag instead of  tag. Please share your thoughts. Poisson Distribution of sum of two random independent variables $X$, $Y$ Consider a "wavefunction" $\psi(x)$, which has a Fourier transform $\tilde \psi(p)$  Suppose that we know, for each $x$, $|\psi(x)|^2$, and that we know, for each $p$, $|\tilde \psi(p)|^2$.  Have we enough information to reconstruct the "wavefunction" $\psi(x)$, that is, obtain the phase of the "wavefunction" for all $x$ (up to a global phase, we are only interesting to the relative phases between the $x$)? Any data for average number of papers per year at different career stages? Lipschitz Condition and Optimization I am reading paper on . I am trying to understand the following statement:     I would like to ask how the Ball doesnot contain the minimum of f? I would appreciate if this could be graphically shown something like following taken from Bayesian Optimization and Data Science Where to place and how to read configuration resource files in servlet based application?