what is null pointer exception

) {StringLine= "";StringBuilderTotal= New StringBuilder();Wrap a bufferedreader around the InputStreamBufferedReaderRd= New BufferedReader(New InputStreamReader(Is));Try {Read response until the endWhile ((Line=Rd.ReadLine()) != Null) {Total.Append(Line);}} Catch (IOExceptionE) { log e (tag, E getlocalizedmessage (), E); } nbsp //Return full String return Total. }

widening reference conversion. See the Java Language specification, sections 5.1.1 and 5.1.4, for details. Parameters:cls the Class object to being Checkedreturns:the Boolean value indicating whether objects of the type CLS can be a Ssigned to objects of this classthrows:nullpointerexception if the specified Class parameter is null. since:jdk1.1439 Native Boolean more ... IsassIgnablefrom (classI have no p

Suppose the current table structure is as follows:Food table field has foodid,name, foreign key businessid, foreign key typeBusiness table field has, name, foreign key typeThe Type table field has Id,name,foodidThe corresponding Pojo generated by Hibernate are Food,business,type, respectively.You need to query Food table section fields, such as name and foreign key BusinessidYou can add a constructor for the food class with only the corresponding memb

-5.1.32.jar:?] at Com.mysql.jdbc.ConnectionImpl.connectOneTryOnly (Connectionimpl.java :2527) ~[mysql-connector-java-5.1.32.jar:?] ... MoreThe problem is not resolved on the Internet, the problem is solved by using MySQL connector version 8. So it should be a problem with the MySQL driver version. 8.0 some variations on the drive class and connection string are as follows:Jdbc.driverclassname=com

): Copy_file:copy/proc/slabinfo to SYS_SLAB_I NFO failed (2), No such file or directory05-07 14:29:53.113:e/aee/dumpstate (16291): Copy_file:copy/sys/kernel/debug/wak Eup_sources to Sys_kernel_wakelocks failed (2), No such file or directoryCourseactivity.javaprivate void Initview () {... Recyclerview = (Recyclerview) Findviewbyid (r.id.rv_activity_course); Presenter.initcourseslist ();} @Overridepublic void Initcourseslist (listthe key to the error is

(partstack.java:1245) at Org.eclipse.ui.internal.PartStack.createControl (partstack.java:662) at Org.eclipse.ui.internal.PartStack.createControl (partstack.java:570) at Org.eclipse.ui.internal.PartSashContainer.createControl (partsashcontainer.java:568).As shown below:(2) If the above error occurs, follow the following 3 steps to resolve:1. First, close the myeclipse working space. 2, then delete under Workspace, "/.metadata/.plugins/org.eclipse.core.runtime/.settings/ Com.genuitec.eclipse

　　|| When the left is true, the expression on the right is not run | When the left is true, the expression on the right is calculated the expression on the right is not calculated when the left side is false the left side

The code in the fragment context is nullpublic class Placeholderfragment extends Fragment{context Context = Getactivity ();}This defines the context as null. Of course, my actual code is not written like this, but this means. It is assumed that the activity will not be empty. In fragment, it

Situation: Is this, the previous time to do a custom Popupwindow, is to write a class, and then inherit Popupwindow, nothing else, but at the time of instantiation, in the 2.3 system directly to the null pointer exception (4.0 and above the system running

Read in Java read. Properties config file null pointer exceptionException in thread "main" java.lang.NullPointerExceptionAt Java.util.properties$linereader.readline (Unknown Source)At java.util.Properties.load0 (Unknown Source)At Java.util.Properties.load (Unknown Source)At Com.bubianchenmo.ch02.TestProperties.main (testproperties.java:15)The path to the loading of the description file should not be modifie

Tags: eclipse auto detect code null pointer potential NULL pointFor this is a very good function, an instant feel strong and powerful AH have wood, will automatically help you detect the null pointer.But when you look at someone else's code, or the server code, the egg hurts

This problem has also plagued me for a long time. Why is it depressing that I used a simulator to test whether it was successful or failed? First, you should remember the role of the following code: // Set service provider Information Through the above program, we obtained the best service provision method, but after many experiments, I found that the best provider obtained each time is the GPS method, thi

HTTP Status 500- type Exception ReportMessageDescription The server encountered an internal error (), prevented it from fulfilling this request.exceptionOrg.apache.jasper.JasperException: Java.lang.NullPointerExceptionorg.apache.jasper.servlet.JspServletWrapper.handleJspException ( jspservletwrapper.java:538) Org.apache.jasper.servlet.JspServletWrapper.service (jspservletwrapper.java:370) Org.apache.jasper.servlet.JspServlet.serviceJspFile (jsps

Exception Handling when the value type obtained by DataRow is NULL or NULL. datarownull // Obtain the DataSet content DataSet ContractDS = dal. GetJHFKStr (jhfubh); // verify whether the DataSet is empty if (! DataSetUtil. IsNullOrEmpty (ContractDS) |! DataSetUtil. isEmptyR

This problem has actually plagued me for a long time. I have asked many people what is "null? What's the purpose? Most people answer: "null is a special 0 defined by the system. Pointing your initialized pointer to it can preven

There is always a newly-introduced Windows programmer asking me what the Windows handle is, and I say you see it as a pointer-like identifier, but obviously the answer doesn't make them happy, and then I say go ask the Niang, they say not too much on the internet is difficul

What is the function of not NULL in the new field when the statement ' AAA ' varchar (one) is not null? What is the function of not NULL in

since future projects will use Spring boot technology as the theme, these days have tried Springboot+dubbo to complete the layering of business architectures, this article mainly records the Dubbo null pointer problems encountered during SPRINGBOOT construction. First, we recommend that you have a channel to this problem and take a look at this articleHttp://www.oschina.net/question/1011127_144093?fromerr=7

These two days I have been confused about how to judge whether the pointer is null. there are usually two methods (assuming P is a pointer ): if (NULL == p) { // ... } if (!p) { } Which method

Graphic:The process is divided into three stages, 1, which is responsible for the following node, and inserts the node into the original linked list 2, copying the random pointer of a subsequent node. 3 split the combined list into two parts.The first part of the code: while (currentnode!=null) {// Copy the node and