java lang exception

Java. lang. NullPointerException, pointerexception when listView. getChildAt (I) BaseAdapter returns the component that can display the number of items on the current screen. Therefore, it uses listView. getChildAt (I ); The returned result is a widget that can be displayed on the current screen. You cannot use the listView. getChildAt (I) method to retrieve widgets other than those that can be displayed on

() Class also has a useful way to create an instance for the class, which is called newinstance (). For example: X. getclass. newinstance (), creates a new instance of the same type as X. The newinstance () method calls the default constructor (No parameter constructor) to initialize the new object. 3. getclassloader () Returns the class loader of the class. 4. getcomponenttype () Returns the class of the Array Component type. 5. getsuperclass () Returns the class that represents the superclass

When I learned the struts2.0 authoritative guide, I encountered the following error: Configuration complete: the following error occurs: Severe: exception starting filter struts2 Java. Lang. abstractmethoderror: org. Apache. xerces. Dom. entimpl. setxmlversion (ljava/lang/string;) V My configuration is as follows: Fiv

Spring version 2.5.5 and JUnit version 4.8.1 use Spring TestContext's SpringJUnit4ClassRunner. This version of JUnit has been used for a long time, and no error will be thrown when writing a simple test. The following error is thrown when you try to write the standard JUnit test code today: Java. lang. NoClassDefFoundError: org/junit/Assume $ AssumptionViolatedExceptionAt org. springframework. test. context

When developing Android WebService, users generally use the WebService server when they accept the returned values. Soapobject = (soapobject) envelope. getresponse (); this is used to accept the returned value, but this method usually produces Java. lang. classcastexception: Org. ksoap2.serialization. soapprimitive. Based on my actual operations and help from others, I finally solved this problem. Use

Check whether there is any exception: Java. Lang. classnotfoundexception: org. springframework. Web. Context. contextloaderservlet Therefore, contextloaderservlet is not loaded successfully, leading to failure in building spring containers in Web. xml! Therefore, when you reference webapplicationcontextutils, java.

An error is reported when you use m2eclipse to import an existing Maven project. Java. Lang. nullpointerexceptionAt org. Apache. Maven. plugin. defaultindescriptorcache $ cachekey. At org. Apache. Maven. plugin. defaultindescriptorcache. createkey (defaultplugindescriptorcache. Java: 62)At org. Apache. Maven. plugin. Internal. defaultmavenpluginmanager. getplugi

Both processbuilder.start()and runtime.exe c can create a local (native) Process and return a Java Process instance representing the Process.The Java. lang. process class can be used to control the process and obtain some information about the process. (1) Call the system command to create the process and obtain the command output. Use runtime.exe c (String cmd )

This problem should be hard to see. If you see it for a while, it is easy to be scared! This exception, as its name implies, is generated by class initialization. It is mainly generated during the initialization of variables, such as private int x = abstract. create ("X1", "X2"). If an exception is thrown in create, it means that the initialization fails and the create operation fails, because of the

Commons LangThe standard Java libraries fail to provide enough methods for manipulation of its core classes. Apache Commons Lang provides these extra methods.Lang provides a host of helper utilities for the Java.lang API, notably String manipulation methods, basic numerical Metho DS, Object Reflection, concurrency, creation and serialization and System properties. Additionally it contains basic enhancements

Package java. Lang. Ref; Import java. Security. privilegedaction;Import java. Security. accesscontroller; // Comment by liqiang Final class finalizer extends finalreference {// class used in the package /** A local method is used to call the Finalize method of any object, because the Finalize method of the object* It i

Miscellaneous (3)-The type java. lang. Object cannot be resolved It is indirectly referenced..., cannotberesolved The type java. lang. Object cannot be resolved. It is indirectly referenced from required. class files This problem occurs when you reference JDK projects of different versions in Eclipse. This is caused

empty string, it is a null object .), The println method of the out object cannot directly operate on the null object. Therefore, the JSP page where code segment 1 is located will throw a "java. lang. NullPointerException" exception.Even if the Object may be empty, some methods of java. lang. Object or Objec

Java. lang. SecurityException: Filter of class org. apache. catalina. ssi. SSIFilter is privileged and cannot be loaded by this web application, privileged Error:1 java. lang. securityException: Filter of class org. apache. catalina. ssi. SSIFilter is privileged and cannot be loaded by this web application 2 at org. ap

I. Problems Found Recently, I was notified by my maintenance colleagues that a software written in Java could not run normally. the following exceptions were found in logs: Java. Lang. illegalstateexception: current state = flushed, new state = coding_end Info | JVM 1 | 2010/11/26 00:01:25 | At java. NiO. charset

Introduction to exceptions and errors in java learning, exception capturing, exception throwing, custom exceptions, finally keywords (small records in java learning), and finally keywords Introduction to exceptions and errors in java learning,

(string, object...) to format strings: // Format a string containing a date.Import java. util. calendar;Import java. util. gregoriancalendar;Import static java. util. Calendar .*; Calendar c = new gregoriancalendar (1995, May, 23 );String S = string. Format ("Duke's birthday: % 1 $ TM % 1 $ te, % 1 $ ty", C );//-> S = "Duke's birthday: May 23,199 5"

Solving Tomcat outofmemoryerror: heap space and permgen spacetomcat March 12th, 2009 It's quite common to run inMemory problemsWhen running some big Java EE application on a Tomcat server.Some of the most commmon errors are like the following ones. This is about a fullHeap Space: Severe: servlet. Service () for servlet JSP threw exceptionjava. Lang. outofmemoryerror:

Java. lang. ThreadLocalIn-depth study of java. lang. ThreadLocal Class 1. What is ThreadLocal? In fact, ThreadLocal is not a local implementation version of a Thread, it is not a Thread, but threadlocalvariable (Thread local variable ). It may be more appropriate to name it ThreadLocalVar. ThreadLocal provides a copy o

12-19 12:12:42. 701: E/androidruntime (626): Java. lang. runtimeexception: unable to start activity componentinfo {COM. CLM. activity/COM. CLM. activity. registactivity}: Java. lang. nullpointerexception 12-19 12:12:42. 701: E/androidruntime (626 ):At com. CLM. activity. registactivity. oncreate (registactivity.