{"id":12607,"date":"2022-10-01T06:48:06","date_gmt":"2022-10-01T01:18:06","guid":{"rendered":"https:\/\/jassweb.com\/solved\/solved-how-do-i-fix-nullpointerexception-and-putting-data-into-nattable\/"},"modified":"2022-10-01T06:48:06","modified_gmt":"2022-10-01T01:18:06","slug":"solved-how-do-i-fix-nullpointerexception-and-putting-data-into-nattable","status":"publish","type":"post","link":"https:\/\/jassweb.com\/solved\/solved-how-do-i-fix-nullpointerexception-and-putting-data-into-nattable\/","title":{"rendered":"[Solved] How do I fix NullPointerException and putting data into NatTable"},"content":{"rendered":"<p> [ad_1]<br \/>\n<\/p>\n<div id=\"answer-50342819\" class=\"answer js-answer accepted-answer js-accepted-answer\" data-answerid=\"50342819\" data-parentid=\"50189536\" data-score=\"0\" data-position-on-page=\"1\" data-highest-scored=\"1\" data-question-has-accepted-highest-score=\"1\" itemprop=\"acceptedAnswer\" itemscope itemtype=\"https:\/\/schema.org\/Answer\">\n<div class=\"post-layout\">\n<div class=\"votecell post-layout--left\"><\/div>\n<div class=\"answercell post-layout--right\">\n<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>Your problem is that you have nested objects and you want to access them via reflection. That is not working!<\/p>\n<p>If your <code>Student<\/code> would only have one exam, you would need to change the propertyNames to this:<\/p>\n<pre><code>String[] propertyNames = { \"name\", \"groupNumber\", \"exam.name\", \"exam.mark\" };\n<\/code><\/pre>\n<p>and the definition of the data provider to this:<\/p>\n<pre><code>IDataProvider bodyDataProvider =\n            new ListDataProvider&lt;&gt;(\n                    students,\n                    new ExtendedReflectiveColumnPropertyAccessor&lt;Student&gt;(propertyNames));\n<\/code><\/pre>\n<p>But your <code>Student<\/code> class has an array of <code>Exam<\/code> objects. How do you want to visualize such a tree structure in a table? NatTable is able to do this, but then you need some more things like the <code>TreeLayer<\/code> etc. And that in turn does not work with your data structure.<\/p>\n<p>I would suggest to first think about what you want to visualize, then check which control fits your needs (is it a table or a tree?), and then check for some tutorials that definitely exist, like the <a rel=\"nofollow noopener\" target=\"_blank\" href=\"http:\/\/www.vogella.com\/tutorials\/NatTable\/article.html\">NatTable Getting Started Tutorial<\/a> or the <a rel=\"nofollow noopener\" target=\"_blank\" href=\"http:\/\/www.vogella.com\/tutorials\/EclipseJFaceTable\/article.html\">JFace Table tutorial<\/a> or the <a rel=\"nofollow noopener\" target=\"_blank\" href=\"http:\/\/www.vogella.com\/tutorials\/EclipseJFaceTree\/article.html\">JFace Tree tutorial<\/a><\/p>\n<\/p><\/div>\n<div class=\"mt24\"><\/div>\n<\/div>\n<p>            <span class=\"d-none\" itemprop=\"commentCount\"><\/span> <\/p><\/div>\n<\/div>\n<p>[ad_2]<\/p>\n<p>solved How do I fix NullPointerException and putting data into NatTable <\/p>\n","protected":false},"excerpt":{"rendered":"<p>[ad_1] Your problem is that you have nested objects and you want to access them via reflection. That is not working! If your Student would only have one exam, you would need to change the propertyNames to this: String[] propertyNames = { &#8220;name&#8221;, &#8220;groupNumber&#8221;, &#8220;exam.name&#8221;, &#8220;exam.mark&#8221; }; and the definition of the data provider to &#8230; <a title=\"[Solved] How do I fix NullPointerException and putting data into NatTable\" class=\"read-more\" href=\"https:\/\/jassweb.com\/solved\/solved-how-do-i-fix-nullpointerexception-and-putting-data-into-nattable\/\" aria-label=\"More on [Solved] How do I fix NullPointerException and putting data into NatTable\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[320],"tags":[323,3424,328,1123],"class_list":["post-12607","post","type-post","status-publish","format-standard","hentry","category-solved","tag-java","tag-nattable","tag-nullpointerexception","tag-swt"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.4 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>[Solved] How do I fix NullPointerException and putting data into NatTable - JassWeb<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/jassweb.com\/solved\/solved-how-do-i-fix-nullpointerexception-and-putting-data-into-nattable\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"[Solved] How do I fix NullPointerException and putting data into NatTable - JassWeb\" \/>\n<meta property=\"og:description\" content=\"[ad_1] Your problem is that you have nested objects and you want to access them via reflection. That is not working! If your Student would only have one exam, you would need to change the propertyNames to this: String[] propertyNames = { &quot;name&quot;, &quot;groupNumber&quot;, &quot;exam.name&quot;, &quot;exam.mark&quot; }; and the definition of the data provider to ... 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