{"id":1419,"date":"2022-08-30T15:16:22","date_gmt":"2022-08-30T15:16:22","guid":{"rendered":"https:\/\/unknownerror.org\/index.php\/2013\/11\/16\/postgresql-jdbc-and-android-nullpointerexception-collection-of-common-programming-errors\/"},"modified":"2022-08-30T15:16:22","modified_gmt":"2022-08-30T15:16:22","slug":"postgresql-jdbc-and-android-nullpointerexception-collection-of-common-programming-errors","status":"publish","type":"post","link":"https:\/\/unknownerror.org\/index.php\/2022\/08\/30\/postgresql-jdbc-and-android-nullpointerexception-collection-of-common-programming-errors\/","title":{"rendered":"PostgreSQL JDBC and Android &#8211; NullPointerException-Collection of common programming errors"},"content":{"rendered":"<p>I&#8217;ve got problem with PostgreSQL JDBC driver on Android.<br \/>\nI use <em>postgresql-9.2-1002.jdbc4.jar<\/em> JDBC driver.<\/p>\n<p>Here&#8217;s my code:<\/p>\n<pre><code>package xyz;\n\nimport java.sql.*;\n\npublic class BaseManager {\n\nprivate String baseUrl = \"jdbc:postgresql:\/\/0.0.0.0\/database?user=username&amp;password=secret\";\n\nprivate Connection conn = null;\n\npublic Integer getUserId(String login)\n{   \n    Integer result = -1;\n    try {\n        Class.forName(\"org.postgresql.Driver\");\n\n        conn = DriverManager.getConnection(baseUrl);\n        \/\/query here\n        conn.close();\n    } catch (SQLException e) {\n        e.printStackTrace();\n    } catch (ClassNotFoundException e1) {\n        e1.printStackTrace();\n    }\n        return result;      \n}\n}\n<\/code><\/pre>\n<p>When I run this method I&#8217;ve got NullPointerException:<\/p>\n<pre><code>04-29 15:24:43.458: W\/System.err(549): org.postgresql.util.PSQLException: Something unusual has occured to cause the driver to fail. Please report this exception.\n04-29 15:24:43.468: W\/System.err(549):  at org.postgresql.Driver.connect(Driver.java:287)\n04-29 15:24:43.468: W\/System.err(549):  at java.sql.DriverManager.getConnection(DriverManager.java:175)\n04-29 15:24:43.468: W\/System.err(549):  at java.sql.DriverManager.getConnection(DriverManager.java:140)\n04-29 15:24:43.468: W\/System.err(549):  at xyz.BaseManager.getUserId(BaseManager.java:20)\n04-29 15:24:43.468: W\/System.err(549):  at xyz.LoginActivity.checkPassword(LoginActivity.java:50)\n04-29 15:24:43.478: W\/System.err(549):  at java.lang.reflect.Method.invokeNative(Native Method)\n04-29 15:24:43.478: W\/System.err(549):  at java.lang.reflect.Method.invoke(Method.java:511)\n04-29 15:24:43.478: W\/System.err(549):  at android.view.View$1.onClick(View.java:3039)\n04-29 15:24:43.478: W\/System.err(549):  at android.view.View.performClick(View.java:3511)\n04-29 15:24:43.478: W\/System.err(549):  at android.view.View$PerformClick.run(View.java:14105)\n04-29 15:24:43.488: W\/System.err(549):  at android.os.Handler.handleCallback(Handler.java:605)\n04-29 15:24:43.488: W\/System.err(549):  at android.os.Handler.dispatchMessage(Handler.java:92)\n04-29 15:24:43.488: W\/System.err(549):  at android.os.Looper.loop(Looper.java:137)\n04-29 15:24:43.498: W\/System.err(549):  at android.app.ActivityThread.main(ActivityThread.java:4424)\n04-29 15:24:43.498: W\/System.err(549):  at java.lang.reflect.Method.invokeNative(Native Method)\n04-29 15:24:43.498: W\/System.err(549):  at java.lang.reflect.Method.invoke(Method.java:511)\n04-29 15:24:43.498: W\/System.err(549):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)\n04-29 15:24:43.518: W\/System.err(549):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)\n04-29 15:24:43.518: W\/System.err(549):  at dalvik.system.NativeStart.main(Native Method)\n04-29 15:24:43.518: W\/System.err(549): Caused by: android.os.NetworkOnMainThreadException\n04-29 15:24:43.528: W\/System.err(549):  at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)\n04-29 15:24:43.528: W\/System.err(549):  at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)\n04-29 15:24:43.528: W\/System.err(549):  at libcore.io.IoBridge.connectErrno(IoBridge.java:127)\n04-29 15:24:43.538: W\/System.err(549):  at libcore.io.IoBridge.connect(IoBridge.java:112)\n04-29 15:24:43.538: W\/System.err(549):  at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)\n04-29 15:24:43.548: W\/System.err(549):  at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)\n04-29 15:24:43.558: W\/System.err(549):  at java.net.Socket.connect(Socket.java:842)\n04-29 15:24:43.558: W\/System.err(549):  at java.net.Socket.connect(Socket.java:785)\n04-29 15:24:43.568: W\/System.err(549):  at org.postgresql.core.PGStream.(PGStream.java:60)\n04-29 15:24:43.568: W\/System.err(549):  at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:101)\n04-29 15:24:43.568: W\/System.err(549):  at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:64)\n04-29 15:24:43.568: W\/System.err(549):  at org.postgresql.jdbc2.AbstractJdbc2Connection.(AbstractJdbc2Connection.java:136)\n04-29 15:24:43.568: W\/System.err(549):  at org.postgresql.jdbc3.AbstractJdbc3Connection.(AbstractJdbc3Connection.java:29)\n04-29 15:24:43.578: W\/System.err(549):  at org.postgresql.jdbc3g.AbstractJdbc3gConnection.(AbstractJdbc3gConnection.java:21)\n04-29 15:24:43.578: W\/System.err(549):  at org.postgresql.jdbc4.AbstractJdbc4Connection.(AbstractJdbc4Connection.java:31)\n04-29 15:24:43.598: W\/System.err(549):  at org.postgresql.jdbc4.Jdbc4Connection.(Jdbc4Connection.java:24)\n04-29 15:24:43.598: W\/System.err(549):  at org.postgresql.Driver.makeConnection(Driver.java:393)\n04-29 15:24:43.628: W\/System.err(549):  at org.postgresql.Driver.connect(Driver.java:267)\n04-29 15:24:43.628: W\/System.err(549):  ... 18 more\n\n04-29 15:24:43.898: E\/System(549): Uncaught exception thrown by finalizer\n04-29 15:24:43.898: E\/System(549): java.lang.NullPointerException\n04-29 15:24:43.898: E\/System(549):  at org.postgresql.jdbc2.AbstractJdbc2Connection.close(AbstractJdbc2Connection.java:651)\n04-29 15:24:43.898: E\/System(549):  at org.postgresql.jdbc2.AbstractJdbc2Connection.finalize(AbstractJdbc2Connection.java:1003)\n04-29 15:24:43.898: E\/System(549):  at java.lang.Daemons$FinalizerDaemon.doFinalize(Daemons.java:182)\n04-29 15:24:43.898: E\/System(549):  at java.lang.Daemons$FinalizerDaemon.run(Daemons.java:168)\n04-29 15:24:43.898: E\/System(549):  at java.lang.Thread.run(Thread.java:856)\n<\/code><\/pre>\n<p>I&#8217;ve no idea what&#8217;s wrong. I know I should use web service (it&#8217;s safer) but I&#8217;ve got SQL hosting only.<\/p>\n<p>Can anybody help me, please?<\/p>\n<p id=\"rop\"><small>Originally posted 2013-11-16 20:49:38. <\/small><\/p>","protected":false},"excerpt":{"rendered":"<p>I&#8217;ve got problem with PostgreSQL JDBC driver on Android. I use postgresql-9.2-1002.jdbc4.jar JDBC driver. Here&#8217;s my code: package xyz; import java.sql.*; public class BaseManager { private String baseUrl = &#8220;jdbc:postgresql:\/\/0.0.0.0\/database?user=username&amp;password=secret&#8221;; private Connection conn = null; public Integer getUserId(String login) { Integer result = -1; try { Class.forName(&#8220;org.postgresql.Driver&#8221;); conn = DriverManager.getConnection(baseUrl); \/\/query here conn.close(); } catch [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1419","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/1419","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/comments?post=1419"}],"version-history":[{"count":0,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/1419\/revisions"}],"wp:attachment":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/media?parent=1419"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/categories?post=1419"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/tags?post=1419"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}