, such as JBoss and WebLogic, share the same principle.
I. java. lang. outofmemoryerror: The full name of permgen space is permanent generation space, which refers to the permanent storage area of the memory. This memory is mainly used by JVM to store class and meta information, when a class is loaded, it will be placed in the permgen space. It is different from the heap region where the class instance is s
When trying to write and deploy a web-service under netbeans 6.0 using Apache Tomcat 6.0, you get a weird error about an incompatibility between the jaxb libraries versions:
* ************************************ Warning * * *********************************** to use JAX-WS 2.1 with JDK 6, newer versions of API jars Need To Be In bootclasspathbefore RT. jar. to do this you can use Java endorsed mechanisms to override what is injava platform. the easie
Java. lang. ThreadLocal
1. OverviewWhat is ThreadLocal? In fact, ThreadLocal is not a local implementation version of a Thread, it is not a thread, but Thread local variable (thread local variable ). It may be more appropriate to name it ThreadLocalVar. ThreadLocal provides a copy of the variable value for every thread that uses the variable. It is a special thread binding mechanism in
Today, we use middlegen to generate HBM for hibernate. XML and java files. After the graphical interface is displayed, click the "generate" button and throw the "Java. lang. the incompatibleclasschangeerror error is confusing. Baidu looked at it and it seems that there are like-minded people, just like me, who successfully generated HBM when they were used for th
Problem:
The shared variable simpledateformat is used in the multithreading method, and the following error is returned:
Java. Lang. numberformatexception: multiple pointsAt sun. Misc. floatingdecimal. readjavaformatstring (floatingdecimal. Java: 1084
Cause:Simpledateformat is thread-insecure and should not be avoided!
Solution:
New simpledateformat ();
Example
MBThreadstacksize 32-bit JDK 1.6 default stacksize about KThe formula is as follows:(2*1024*1024-64*1024-130*1024)/325 = 5841The formula calculates 5841, which is basically the same as the practice 5602 (there is a deviation because reservedosmemory cannot be accurate)
According to the formula, the more JVM memory you provide, the less threads you can create, and the more likely java. Lang. outofmemoryerro
07-12 07:34:04. 411: Warn/system. Err (533): Java. Lang. illegalstateexception: Database not open07-12 07:34:04. 440: Warn/system. Err (533): At android.database.sqlite.sqlitedatabase.exe csql (sqlitedatabase. Java: 1759)
These two rows are error messages
OnCode. However, database not open is reported this time. This problem has not occurred before.
After chec
Depressing: when calling JNI, there will always be // 08-14 10:26:28. 734: Error/androidruntime (30101): Java. Lang. unsatisfiedlinkerror: writecmd
After a morning, I finally couldn't help it. I asked in the group that I had made a mistake. I compiled a. h file, not a. c file .... Tragedy.
Call the JNI step,
1. Write the Java and native methods and call the Li
Package java. Lang;
/**** Use methods that inherit this interface to use the thread mechanism. The run method will be called by the thread,* This method defines the actual operations of threads. The purpose of using this interface is to increase flexibility,* Java only supports one parent class, but multiple interfaces can be implemented.* This eliminates the ne
During download, the file can be correctly downloaded, but an error is always reported.
Java. Lang. illegalstateexception: getoutputstream () has already been called for this response
Solution:Outside the scope of java scripts (that is, outside the scope of CodeCharacters such as space, carriage return, or line feed cannot be correctly downloaded if any. If you
Javax. servlet. ServletException: java. lang. NoClassDefFoundError: javax/el/ELResolver error solution,
Today, you don't need eclipse, myeclipse, or other development tools. When writing a JSP page (a little dead), you suddenly encounter problems that you have never encountered before. The error is as follows:
HTTP Status 500 - java.lang.NoClassDefFoundError: javax/el/ELResolvertype Exception reportmessage
The Android program depends on a Library program B. The requirements for converting formatted json strings to standard json strings are used in program B.
Public static String jsonFormatter (String uglyJSONString) {Gson gson = new GsonBuilder (). setPrettyPrinting (). create (); JsonParser jp = new JsonParser (); JsonElement je = jp. parse (uglyJSONString); String prettyJsonString = gson. toJson (je); return prettyJsonString ;}
However, in the Android program
JsonMappingException: (was java. lang. NullPointerException)An exception is reported when java objects are serialized using jackson:
com.fasterxml.jackson.databind.JsonMappingException: (was java.lang.NullPointerException) (through reference chain: com.chanjet.gov.Student["age"]) at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingEx
Recently, when writing a test script in Groovy, a problem occurs. In Groovy 1.5.7, groovy reads a built-in dom Processing Package (org. w3c. dom), and groovy script used in the watij library contains the xml-apis.jar conflict, because the version is not the same.
The following error is reported:
Caught: java. lang. LinkageError: loader constraint violation: loader (instance of
After checking the informat
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