java lang classcastexception

SummaryAs an Enterprise Java developer, we always need to implement various functions, such as parsing XML, using HTTP, verifying input and processing dates. The objective of using the Jakarta Commons project is to create components responsible for processing all such common tasks, saving time and allowing you to focus on core business solutions. In this article, we will briefly introduce the Jakarta Commons project, and then demonstrate how to use th

Http://blog.csdn.net/jxzxm1_2/article/details/2499751 An exception occurs when a Java program is used to query a large amount of data from the database:Java. Lang. outofmemoryerror: Java heap SpaceThis exception is thrown if 98% is used for GC and the available heap size is less than 2% in JVM.JVM heap setting refers to the setting of memory space that JVM can a

Addnode. sh failed, log file error PRKC-1025 java. lang. OutOfMemoryError: Java heap space,Environment: Linux 5.5 + RAC 11203 Problem description: The command to add a cluster member is as follows: $ GRID_HOME/oui/bin/addNode. sh-silent "CLUSTER_NEW_NODES = {X3850AR}" "CLUSTER_NEW_PRIVATE_NODE_NAMES = {X3850AR-priv}" "CLUSTER_NEW_VIRTUAL_HOSTNAMES = {X3850AR-vip

Error querying database. Cause: java. lang. IllegalArgumentException: Mapped Statements collection does not contain value ..., Querying After compiling and running the web successfully, you do not need to connect to the database on the accessed page. If you do not call the object class through reflection, no error is reported,The error message is as follows: [WARNING]Org. springframework. web. util. NestedS

Class hierarchy Java. Lang.Object Java. Lang.Boolean(Implements java. Lang. Comparable Java. Lang.Character(Implements java. Lang. Comparable

From: http://hi.baidu.com/dearfenix/blog/item/1b0ce80e64ca12ce7bcbe109.html It has always been known that JVM heap size can be set, and Java programs are always written/debugged using eclipse. Run the program by adding parameters on the command line or console. Symptom: In the eclipse configuration file eclipse. set-vmargs-xms500m-xmx1024m in ini. Java still appears when you run or debug some memory-consu

source code. If classpath is not specified or an error is specified when you run the Java program, the virtual machine cannot find the correct path, and thus the java. Lang. noclassdeffounderror: exception in thread "Main" error occurs. Therefore, when such a similar problem occurs, you should first check whether the classpath has a problem. In addition, when we

Exception Org. apache. jasper. jasperexception: javax. servlet. servletexception: Java. lang. outofmemoryerror: Java heap spaceorg. apache. jasper. servlet. jspservletwrapper. handlejspexception (jspservletwrapper. java: 505) Org. apache. jasper. servlet. jspservletwrapper. service (jspservletwrapper.

Java record-87-java. lang. reflect. ArrayThe java. lang. reflect. Array class provides various static methods for dynamically creating and accessing Array elements. Import java. lang. r

Take the tomcat environment as an example. Other WEB servers, such as jboss and weblogic, share the same principle.1. java. lang. OutOfMemoryError: PermGen spacePermGen space stands for Permanent Generation space, which is the Permanent storage area of the memory,This memory is mainly used by JVM to store Class and Meta information. When the Class is loaded, it will be placed in PermGen space,Unlike the Hea

Java. Lang. outofmemoryerror: Java heap space and its processing During development, JavaProgramAn exception occurred when querying a large amount of data from the database:Java. Lang. outofmemoryerror: Java heap Space This exception is thrown if 98% is used for GC and t

The root cause of this problem is that the default heap size of the JVM virtual machine is 64 MB, which can be achieved by setting the maximum and minimum values. There are several ways to set the heap size. 1. You can add java_opts =-xms64m-xmx512m to change the system environment variable in windows. 2. If Tomcat is used, in windows, add: e: \ Program Files \ apache-Tomcat-6.0.29 \ bin \ Catalina. BAT: Set java_opts =-xms512m-xmx512m The location is added to the row REM guess catali

When I started my computer at work in the morning, I found a problem with the application startup. The prompt was: Java. Lang. noclassdeffounderror: javax/transaction/transactionmanager. So I googled it and it turned out to be missing JTA. jar. It's strange that it was good. Why is it missing today? Is there a problem with eclipse. JTA. jar: 1, http://java.sun.com/products/jta/ download class files, and th

Java. lang. OutOfMemoryError Cause:The following are common examples: 1. The amount of data loaded in the memory is too large, such as extracting too much data from the database at a time; 2. There are references to objects in the Collection class, which are not cleared after use, so that JVM cannot be recycled; 3. There are endless loops or loops in the code that generate too many repeated object entities

Start learning Java and write some code to demonstrate the main functions and function usage of each class. The basic idea is to create a package structure based on the Java source code package structure and write a demo class for each class. My basic classes: Package tjava. testlang; DEMO code of the Boolean class: Package tjava. testlang; Verification class: Import tjava. testlang. *; Other classe

Exception in thread "main" java. lang. OutOfMemoryError: Java heap space, exceptioninthreadException in thread "main" java. lang. OutOfMemoryError: Java heap space Solution Problem descriptionException in thread "main"

From: http://hi.baidu.com/cjxgotofly/blog/item/ef981434e2e112355ab5f55f.html Java. Lang. outofmemoryerrorTroubleshooting Cause:The following are common examples: 1. The amount of data loaded in the memory is too large, such as extracting too much data from the database at a time; 2. There are references to objects in the Collection class, which are not cleared after use, so that JVM cannot be

An error occurred when Tomcat was started today. Severe: end event threw exceptionJava. Lang. illegalargumentexception: Can't convert argument: NULLAt org. Apache. tomcat. util. introspectionutils. Convert (introspectionutils. Java: 999)At org. Apache. tomcat. util. digester. callmethodrule. End (callmethodrule. Java: 523)At org. Apache. tomcat. util. digester. R

Java. Lang. exceptionininitializererror Initialization program error. Thrown when an exception occurs during the execution of a class static initialization program. Static initialization programs are static statement segments directly included in the class. Java. Lang. illegalaccesserror Illegal access error. This exce

Java. lang. NoClassDefFoundError: org/jboss/util/file/ArchiveBrowser $ FilterAt org. hibernate. ejb. HibernatePersistence. createEntityManagerFactory (HibernatePersistence. java: 119)At javax. persistence. Persistence. createEntityManagerFactory (Persistence. java: 83)At javax. persistence. Persistence. createEntityMan