java lang nullpointerexception java

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

The Java class cocould not be loaded. java. Lang. unsupportedclassversionerror Yesterday, I replaced a jar package and ran it. The system reported the following error: The Java class cocould not be loaded. java. Lang. unsupporte

Source: http://apps.hi.baidu.com/share/detail/23485743Problem descriptionException in thread "Main"Java. Lang. outofmemoryerror: Java heap Space Solution [go]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 c

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

Issue: When we use Java Dynamic proxy, method. invoke () is a necessary step to call the real method we want. but once this method triggers an exception during execution, the final exception printed out is always "Java. lang. reflect. invocationtargetexception ". so,How can we know that which exact exception caused JVM throw invocationtargetexception? Solu

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

. classnotfoundexception ".Immediately exiting rose results in a "Java. Lang. nullpointerexception" WarningAnd the Rose does not respond. Cause: This is usually due to a broken Microsoft Java Vm, but may be due to a missingRegistry entry. Resolution: First, confirm that the Windows registry value "trustedclassp

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 memory: Method 1: Find Eclipse/eclipse. ini,

Java. lang. OutOfMemoryError: Java heap space exception may be caused by the JAVA stack setting being too small. There are roughly two solutions based on the answers on the Internet: 1. Add set JAVA_OPTS =-Xms200m-Xmx512m at the beginning of D:/apache-tomcat-6.0.18/bin/catalina. bat. Note: The setting takes effect o

Several common exceptions during Spring development (3): java. lang. classCastException: com. sun. proxy. $ Proxy4 cannot be cast to com.edu. aop. arithmeticCalculatorImpl at com.edu. aop. main. main (Main. java: 11 ), This exception was encountered during Spring case development. Paste the complete exception information: Exception in thread "main" java.lang.Clas