nullpointerexception processing

Goodbye NullPointerException. Processing of null in Kotlin (KAD 19), kotlinnull By Antonio Leiva Time: Apr 4, 2017 Link: https://antonioleiva.com/nullity-kotlin/ One of the most important parts of Kotlin: It took me a long time to write an article. The creator of Tony Hoare's "null" concept,Billions of errors". When writing Java code, null is the most error-prone pointer. If you are observing the Bug

My exceptions-java. lang. NullPointerException, nullpointerexception I believe everyone is very familiar with this exception. I believe that everyone has met this exception in their programming career. During the development of 3.1 of colleges and universities, such errors were thrown out again. This is a small bug, but when it comes to it, it will make you sick for half a day, because the program will be s

It 's written in front . This demo shows how to troubleshoot a @transactional-induced nullpointerexception. Https://github.com/hengyunabc/spring-boot-inside/tree/master/demo-Transactional-NullPointerException Positioning NullPointerException's Code Demo is a simple spring transaction example that provides one of the following Studentdao and declares the transaction with @transactional: @Component @Transact

About remote connection (including using Eclipse to connect) SqlServer2005:When you confirm that the URL, driver loading, user name, and password of the connection are correctly configured, java is still thrown. lang. for NullPointerException, open

When writing Java programs, especially JSP/Servlet and other things, there is often such a situation: of course, when you have worked hard to lay down thousands of lines of letters, write the last braces; when you run this program for debugging, The nullpointerexception message suddenly appears. Are you very disappointed. In the past, I would have picked up the cup on the table. After more than a year of playing letters, I gradually summed up some exp

Analysis of Java NULL pointer exceptions (1) The Java language has an "exception mechanism" to handle special cases in the program. For example, if the divisor is zero, it is an "exception ".The NULL pointer exception java. Lang. nullpointerexception is a common exception. Let's talk about its analysis method.When the basic java data type is used, the value of the variable is either the default value. If no value is assigned to the variable, the prog

The following lists the NullPointerException that often occurs when we learn java and its solutions. 1. Null Pointer Error java. lang. nullPointerException uses the Basic JAVA data type. The value of the variable is either the default value. If no value is assigned to the variable, the program cannot compile the variable. Therefore, the basic JAVA data type (double, float, boolean, char, int, long) generall

The exception of the null pointer is disgusting, I am afraid is the actual application of the most frequently occurring anomalies, the following is how to avoid nullpointerexception appearance of the technique Before using an object, it is best to know if they are possible null, and if not, use the IF statement to determine whether to use an object, or to traverse a collection, you need to make sure that they are non-empty. It's a rule that w

When using Elasticsearch, it is necessary to use the Parent-child API to create a mapping for the parent, and a common nep--nullpointerexception occurs when the child's field fields are dynamically updated. The log log exception is as follows:[2016-04-0112:04:53,986] [INFONBSP;] [rest.suppressed]/test/_mapping/name/ params:{index=test,type=name}java.lang.nullpointerexception atorg.elasticsearch.index.mapper.mappedfieldtype.checkcompatibility (MappedFi

1. Opening remarksI believe that the SSH beginner must have encountered this problem, but it is not the solution, understood after the epiphany.2, problem descriptionThe program implementation process is called UserService in Useraction , and theDAO class is called in the UserService implementation class . a nullpointerexception error occurred during the operation of the program in the console:The invocationtargetexception function is entered durin

When simplifying the code associated with a single table in MySQL 2nd (version 5.4), Lu xiheng encountered a null pointing exception. After analysis, it was a logic problem and we made a record here. Environment: Mac OS X 10.9.5, intellij idea 13.1.5, hadoop 1.2.1 The modified code is as follows. In the reduce stage, nullpointerexception is encountered. 1 public class STjoinEx { 2 private static final String TIMES = "TIMES"; 3 4 public stati

ZendStudioforEclipse's java. lang. NullPointerException solution. Of course, this item is very memory-consuming and will not be recommended for configuration. recently, I found that this error occurs when ZendStudioforEclipse is enabled after the PHP project is created. Aninterna is very memory-consuming, and it is not recommended if the configuration is almost complete. Recently, this error occurs when Zend Studio for Eclipse is enabled after the PH

Nullpointerexception It's so ubiquitous that I ran it out accidentally. Debugging is required for the victim for half a day. Note the following secret points: For example, for native type encapsulation such as integer, they can be used in the place where native types are used, and they will be implicitly converted by themselves. However, if the conversion is null before the conversion, it will be a tragedy, the

I followed the tutorial, created a new activity through the wizard, and when I ran the OnCreate method called the Findviewbyid () method times the wrong nullpointerexception.Layout XML (fragment_main.xml):Xmlns:tools= "Http://schemas.android.com/tools"Android:layout_width= "Match_parent"android:layout_height= "Match_parent"android:paddingbottom= "@dimen/activity_vertical_margin"android:paddingleft= "@dimen/activity_horizontal_margin"android:paddingright= "@dimen/activity_horizontal_margin"androi

Android.view.choreographer$callbackrecord.run (Choreographer.java : 725)12-19 17:32:41.822:e/androidruntime (1894): at Android.view.Choreographer.doCallbacks (choreographer.java:555)12-19 17:32:41.822:e/androidruntime (1894): at Android.view.Choreographer.doFrame (choreographer.java:525)12-19 17:32:41.822:e/androidruntime (1894): At Android.view.choreographer$framedisplayeventreceiver.run ( choreographer.java:711)12-19 17:32:41.822:e/androidruntime (1894): at Android.os.Handler.handleCallback (

错误：java.lang.NullPointerException11-15 09:04:21.023: E/AndroidRuntime(4057): at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:591)11-15 09:04:21.023: E/AndroidRuntime(4057): at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1416Execute code:if (mcurtransaction! = null) { Mcurtransaction.commitallowingstateloss (); if (manager! = null) manager.executependingtransactions ();Cause: If the fragment is

Today, when I was working on struts, I encountered the java. Lang. nullpointerexception: module 'null' not found error. I was depressed for a long time, The Web. xml file is not configured./WEB-INF/struts-config2.xml If this problem occurs, try this method! It is inconvenient to change eclipse, and it is inconvenient to find the struts plug-in 3.1.2. I still think JBuilder is good...

You have not set the object reference to the instance of the object. NullReferenceException, nullpointerexception not handled During the reconstruction of the data center, various problems were encountered, including the following: "The object is not set to the instance of the object", for example: This problem is really common and tangled. In particular, many people next to me have encountered this problem during this time. After debugging for many

The so-called null pointer exception is because the property or method is called with null (NULL). Null means there is no such object, since there is no such object, then to invoke his properties and methods, it will report an exception. Null pointer exception.General report Java.lang.NullPointerException for the following reasons: 1. String variable uninitialized; 2. An object of the interface type is not initialized with a specific class, for example: 3. List lt; Will error 4. List lt = new

(secondarynamenode.java:350)At Org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode.doCheckpoint (secondarynamenode.java:314)At Org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode.run (secondarynamenode.java:225)At Java.lang.Thread.run (thread.java:619)This is caused by setting access time on a non-existent file.To modify the Hadoop source code:index:src/hdfs/org/apache/hadoop/hdfs/server/namenode/fsdirectory.java======================================== ===========================---sr