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POJava library compatibility issue - NULL Pointer exception
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  1. POJava library compatibility issue - NULL Pointer exception
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    copied!<p>I'm trying to create a Java swing application and I'm trying to use a class I wrote for Android. I'm having trouble executing a http post because I'm getting a NULL pointer exception.</p> <pre><code>private static String httpPost(ArrayList&lt;NameValuePair&gt; constraints, URI uri) throws ClientProtocolException, IOException { HttpClient httpclient = new DefaultHttpClient(); HttpPost httppost = new HttpPost(uri); try { httppost.setEntity(new UrlEncodedFormEntity(constraints)); } catch (UnsupportedEncodingException e) { throw (new IllegalArgumentException("Constraints: " + constraints.toString())); } HttpResponse response = httpclient.execute(httppost); return isToString(response.getEntity().getContent()); } </code></pre> <p>Stack trace: </p> <pre><code>Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at org.apache.http.entity.StringEntity.&lt;init&gt;(StringEntity.java:70) at org.apache.http.client.entity.UrlEncodedFormEntity.&lt;init&gt;(UrlEncodedFormEntity.java:78) at org.apache.http.client.entity.UrlEncodedFormEntity.&lt;init&gt;(UrlEncodedFormEntity.java:92) at connection.Server.httpPost(Server.java:130) ... </code></pre> <p>On android the org.apache.* package is included in android-8.jar. It just wont work with the libs i've downloaded from <a href="http://hc.apache.org/downloads.cgi" rel="nofollow">here</a> (HttpCore 4.2.1). </p> <p>The NullPointerException is thrown on the following call <code>new UrlEncodedFormEntity(constraints)</code>. I've checked the parameter <code>constraints</code> using the debugger and it's perfectly fine and contains what it's supposed to contain.</p> <p>Am i doing something wrong? It seems to me that there is a problem with the lib. I've been looking for previous versions on <a href="http://hc.apache.org/downloads.cgi" rel="nofollow">the site</a> but it seems that there are none there.</p> <p><strong>EDIT:</strong> It just occurred to me to download the sources to see exactly where the exception is beeing thrown (line 70):</p> <p>org.apache.http.entity.StringEntity</p> <pre><code>68: Charset charset = contentType != null ? contentType.getCharset() : null; 69: if (charset == null) { 70: charset = HTTP.DEF_CONTENT_CHARSET; 80: } </code></pre>
 

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