java lang nullpointerexception error in java

Just getting started with struts2, when passing parameters to the action, the system prompts an error all morning: Java. Lang. nosuchmethodexception: com... Action, java. Lang. Class. getmethod ()...... Solutions found on the Internet. It is found that actions in struts2 can

Author: Xiaolou Original Website: Http://blog.vonno.com/33993/viewspace_1245 17:50:57/personal classification: Knowledge Summary Cause: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 tha

must be set to the same, and-xmn is the-xmx value of 1/4.The-XMS-xmn setting of heap size should not exceed the physical memory size. Otherwise, the system prompts "error occurred during initialization of VM cocould not reserve enough space for object Heap ". ========================================================== ============================After one night of hard work, I finally completed a program for replacing the specified string with a file

Environment: eclipse3.3.0 + myeclipse5.5.1ga (spring2.0 + struts1.1 + hibernate3.1) The error is: Java. Lang. nosuchmethoderrorCode:15:20:54, 093 error contextloader: 203-context initialization failedOrg. springframework. beans. factory. beancreationexception: Error creating

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

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}"

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 r

In the past few days, a part-time employee's information entry system has encountered an error where hibernate cannot query the specified condition data. Now we can find a solution: The error message is as follows:HTTP status 500- -------------------------------------------------------------------------------- Type exception report Message Description the server encountered an internal

Eclipse memory overflow error: Java. Lang. outofmemoryerror: Java heap space. 1. view memory: Workspace /. metadata /. plugins/org. eclipse. core. runtime /. settings/org. eclipse. UI. prefs, add show_memory_monitor = true to it, and restart eclipse to view the memory usage in the lower left corner. 2. Modify the me

Java. Lang. Error: unresolved compilation problem:Constants. centeryearsreportclasstime cannot be resolved At com. sencloud. DH. OA. Action. Report. centeryearsreportaction. statisticsrevenue (centeryearsreportaction. Java: 255)At com. sencloud. DH. OA. Action. Report. centeryearsreportaction. statisticscenter (center

Java. lang. error: Unresolved compilation problem: Constants. CENTERYEARSREPORTCLASSTIME cannot be resolved at com. sencloud. dh. oa. action. report. centerYearsReportAction. statisticsRevenue (CenterYearsReportAction. java: 255) at com. sencloud. dh. oa. action. report. centerYearsReportAction. statisticsCenter (Cente

I recently encountered more than N errors when I configured the android Development Environment on Ubuntu. Let's talk about it. If there is a similar error, just modify it. So far, the ADT version has been upgraded to 18. When the SDK version is upgraded to 4.0.3, the ADT version is required to be 17 or later. If any problem occurs after the upgrade, it may be caused by the JDK version. Please note that, adt17 requires that the JDK version be in JDK 1

Here we use Http://blog.csdn.net/oscar999/article/details/7305489 Jdbctest. Java source file in 1. Use the compilation command in JDK to compile the. Class file. "C:\Program Files\Java\jdk1.6.0_24\bin\javac.exe" -cp ojdbc14.jar; JDBCTest.java 2. Run the Java command in jdk1.5. "C:\Program Files\Java\jdk1.5.0_14\bin\

There are two JVM memories for increasing the memory size. One is the eclipse memory. To increase JVM memory: Open the myeclipse software and select window --> preferences --> JAVA --> installed jres --> edit, as shown in: To increase the eclipse memory: 1. Open eclipse software, select Run from the menu bar, and select debug configurations... from the level-2 menu, as shown in. 2. Select the (x) = arguments tab in the pop-up window. In t

InvalidLOCheader (badsignature) error and java. lang. ClassFormatError: com/mysql/jdbc Error 1. The error message is as follows: SEVERE: Resource read error: Could not load org.springframework.jmx.support.MetricType.java.util.zip

During RCP Eclipse plug-in development, the following error is always reported when the management software interface is started: ! Entry org. Eclipse. UI. workbench 4 0 18:44:21. 306! Message warning: prevented recursive attempt to activate part Org. gluster. storage. management. console. views. clustersummaryview while still in the middle of activating part Org. gluster. storage. management. console. views. navigationview! Stack 0Java.

the memory (the custom Math class is not loaded). When the main method is executed, the method does not exist. Therefore, an error indicating that the method does not exist is reported. That is to say, by default, the JVM will not load our custom Math class. Run the MyMath class directly, and the output is as follows: Java. lang. SecurityException: Prohibited pa