georgeguwenzhong-优快云博客

javax.naming.CommunicationException: remote side declared peer gone on this JVM.

javax.naming.ServiceUnavailableException [Root exception is java.net.UnknownHostException: XXXXX001] javax.naming.CommunicationException [Root exception is java.net.ConnectException: t3://X.X.X.X:...

2012-07-11 09:44:15 868

原创 Generate special format numbers

DecimalFormat df = new DecimalFormat("999000");df.format(10); will output "999010"

2012-04-27 00:06:07 175

原创 Singleton Service in Weblogic Cluster

http://blog.youkuaiyun.com/mobicents/article/details/6285932

2012-03-21 00:12:01 196

java.util.ConcurrentModificationException

Where ConcurrentModificationException raisedCase 1: update value Entries during traverse Map in same Threadjava.util.ConcurrentModificationException will be raised in following java code: Ma...

2012-03-20 18:10:38 207

Scheduled ThreadPool Executor suppressed or stopped after error happen

ScheduledThreadPoolExecutorExecution periodic Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period; tha...

2012-03-20 16:54:19 158

原创 Memory Leak analyze

Shallow Heap Size Shallow size is the amount of memory allocated to store the object itself, not taking into account the referenced objects.Retained Heap Size Retained size of an object is its s...

2012-03-12 06:21:05 123

Wheels: Common utilities reuse and design

Search-->Copy-->Small Modification-->Delivery with product...-->Search again-->Copy and modify again-->...OrRewrite-->Test-->delivery with product...Rewrite-->Test--&g...

2012-02-18 05:57:05 135

Java Exception Design

Talk something used to happen in projects. Java basic Exception Struts global exception handler design.

2012-02-18 05:36:26 150

Batch Processing

Batch Processing has to be concerned during enterprise application design and integration test.Batch Processing ConcernsNormally, it refer to three problems.Memory Resource consumingThere coul...

2012-02-18 05:34:25 167

JMX in Weblogic

Here I would like to list some topics I used to search or study.MBean Servers in WeblogicThe JVM for an Administration Server maintains three MBean servers provided by BEA and optionally maintains...

2012-02-17 19:20:56 181

Clean Code (1): Meaningful Method Signature

Remove useless methodRemove method never referenced If method or API is not used any more, it is better to remove them rather than keep them. Version control/management tools should/will kee...

2012-02-10 21:31:17 131

Answer Questions or Give solutions Consistent and Entirely

Before answer a technical problem or give workaround to a issue, make sure:Understand the context of people who ask questions.Where the issue comes from or where it could from.Find out solutio...

2012-02-10 18:59:21 271

Continuous Improvement (1): Delivery Features as Easy and Stable as possible

We should delivery features as easily as possible. We should delivery features as stable as possible. In development phase, make sure all error use case coverred and valid before submitting. Someti...

2012-02-10 18:22:30 135

Java String Charset Encoding

CharsetCharset is a named mapping between sequences of sixteen-bit Unicode code units and sequences of bytes. 1 byte = 8 bits, byte represent the int value from 0x00 through 0xFF. In ASC-II, we...

2012-02-09 00:28:48 251

Weblogic 11g JSP cache

Normally, jsp_servlet classes will be cached by Weblogic 11g in: {BEA_WLS}\user_projects\domains\yourdomain\servers\yourserver\tmp\_WL_user\your_app_name We always meet a strange problem: why J...

2012-01-31 00:41:04 192

Bad version number in .class file

Bad version number in .class file Mainly happened because of running Java class in a lower JDK version but it was compiled in higher JDK version. How to Check Java Class Version Execute comman...

2012-01-27 00:35:14 135

User Data Header in SMPP SUBMIT_SM

SMPP optional Parameters for concatenation and port addressing SMPP concatenation related optional parameters: (sar_msg_ref_num, sar_total_segments, sar_segment_seqnum) SMPP po...

2012-01-25 22:30:39 448

Error code "075" in SMPP Delivery Receipt

SMPP provides for return of an SMSC delivery receipt via the deliver_sm or data_sm PDU,which indicates the delivery status of the message. The informational content of an SMSC Delivery Receipt m...

2012-01-25 22:21:57 414

Migrate Weblogic 9.2 to Weblogic 11g : Spring Application

Here I would like to list the problems I met during Spring application migartion from Weblogic server 9.2 to Weblogic Server 11g. Hibernate cannot be loaded properly [java] 11:53:29,008 ERRO...

2012-01-25 22:02:48 187

Hibernate Configuration Properties

Hibenate configuration parametersHere is a general hibernate session configuration file: hibernate.cfg.xml<?xml version="1.0" encoding="utf-8"?><!DOCTYPE hibernate-configuration PUB...

2011-12-29 18:03:41 173

Spring Security: from Acegi to Spring Security 3.0

I would like to summarize how we use acegi in our projects. Recently, we plan to move acegi to spring security 3.0, i will list the problems here.

2011-12-29 06:29:31 85

JAAS: Java Authentication and Authorization Service

Subject: /** * <p> A <code>Subject</code> represents a grouping of related information * for a single entity, such as a person. * Such information includes the Subject's id...

2011-12-29 06:26:00 213

Professional Java Security

<<Professional Java Security>> is a wonderful guideline for java security developer.It covers the following topics, any problem please refer to the book:Overview of enterprise securi...

2011-12-29 04:27:40 177

SecurityManager in Java

Java Security ManagerJava SecurityManager javadoc: /** * The security manager is a class that allows * applications to implement a security policy. It allows an * application to deter...

2011-12-29 04:14:06 188

Unique Identifier generation in Java Application

During application design, there are always some requirements to assign unique identifer for specific Objects. System MillSeconds + RadomData base use Sequence use a column in table...

2011-12-23 06:17:09 132

log4j source code analyze

org.apache.log4j.LogManager.javaA singleton class implemented by a set of "static" properties and methods. /** * Use the <code>LogManager</code> class to retreive {@link Logger} ...

2011-12-23 06:09:35 134

log4j:ERROR Attempted to append to closed appender named [*]

During system running, sometimes we can see the error message from log4j log: log4j:ERROR Attempted to append to closed appender named [*]. Here I would like to talk about one use case whic...

2011-12-22 18:05:35 700

Workflow Engine: OSWorkflow

OSWorkflow ReferenceOSWorkflow is now not maintenenced by provider. See more information from: http://www.opensymphony.com/ Explain osworkflow basic concept and how to use osworkflow. ...

2011-12-21 00:44:29 228

Java Threads

Some Concepts in Thread ControlHere I would like to list some concepts I used to be not aware of.Daemon ThreadsDaemon threads are service providers for other threads running in the same process ...

2011-12-20 23:18:18 681

ORM: Hibernate and Eclipselink

Orm Hibernate EclipselinkAssociation mapping treatment Descript how both ORM manage association

2011-12-20 05:40:40 120

Hibernate Extension

Second level cache Ehcache in hibernate Hibernate batch load Use hibernate batch load feature to refresh a set of managed data in order to avoid memory leak and improve performance.Hib...

2011-12-20 05:39:05 144

AOP(3): Spring AOP

AOP ReferencesPlease refer to Spring Framework AOP specification site for more details on spring aop concepts.General introduction to Aspect-Oriented ProgrammingAspectAspect is "cross-c...

2011-12-20 05:24:55 107

log4j Usage

In our projects, there are always the following questions for log4j integration:log4j could be exist in several jars, is there any conflict? For example, each components has their own logging imple...

2011-12-19 23:01:53 202

Java is Pass-by-Value or Pass-by-Reference?

What's saved in Object Reference?We can treat the Java Object will be managed in two parts: Obejct definition and its reference to Memory Heap which contains object's attribute and data content...

2011-12-19 19:18:33 125

UML Extension

Classes Relationship in UMLAssociation"Association" on behelf of the reference between Class A and Class B. Association allows one class to know the methods and attributes of referenced class.N...

2011-12-15 06:06:37 129

Oracle Index Usage

Like a hash mapping for record's address. By default sql query Will lead to entire schema scanning. Index can be Used to get target record fastly and easily.

2011-12-15 05:26:43 154

java.util.Properties: a subclass of java.util.Hashtable

I met a problem this afternoon when test following souce snap: Properties p = new Properties(); #1p.put("smsc.adapter.driver.number", 2); #2int driverNumbers = Integer.intValue(p.getProperty...

2011-12-13 06:57:25 107

JMX Usage

There is long times since last time I did use JMX in my project. Too long to remember all details on how to use JMX. We can refer to Java website to get more details on how to use JMX: http://www.or...

2011-12-13 06:22:21 112

Using Taglib to Implement Dynamic UI

What's Taglib?Taglib is a JSP extension feature to allow developer to define complex UI interactivation in java code. It can simplify the code and logical in JSP page and we can control the JSP pag...

2011-12-12 06:13:44 119

Testing in Java

QA is important for production. Testing is important for QA. Here I would like to talk about testing in Java application development. It won't refer to project process/life cycle control, I will on...

2011-12-02 05:59:58 130

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