10 J2EE project development riskprestashop

When you started to organize an enterprise Java project, to start at the same time as the reincarnation of several magic to throw the ball: the owners deal with the relationship, continuous and long process of design and development, and maintaining a sound and integrity, and so on. Each However, all of these risks are completely avoided.
When you started to organize an enterprise Java project, to start at the same time as the reincarnation of several magic to throw the ball: the owners deal with the relationship, continuous and long process of design and development, and maintaining a sound and integrity, and so on. Each However, all of these risks are completely avoided. The author Humphrey Sheil of a threat to the success of enterprise level Java projects 10 risk, and to list the strategies of risk avoidance methods.
-------------------------------------------------- ------------------------------
In the past period, I worked as a programmer, senior designers and architects, etc., seen very good enterprise-level Java projects, but also had a bad experience, or even very Sometimes I ask myself,prestashop, why a project can succeed, and the other is to fail? Difficult to define some kind of rules or standards to show how different the success of projects, J2EE projects are no exception. But on the contrary, we can go up from all angles and levels of failure to inspect the project, if the well to avoid these risks, the project can succeed. In this article, I will present the top 10 enterprise-class Java project risk, for reference.
In a variety of risks, some risks only delayed the progress of the project, and some brought some unnecessary work,virtuemart template, while others will be to completely eliminate the possibility of success. However, if there is enough advance preparation and a clear understanding, then is not inevitable. It's like if you are a traveler, you clearly know in what direction the road ahead, made full preparations, but also know where there is risk of a guide, this will be more successfully reach their destination.
In this paper, the following structure to describe the risk:
Risk name: the risk of title (in bold)
Project Stage: In which phase of the project risks will occur
Of stages: what will affect the future stages of
Symptoms: Symptoms of the risk arises
Circumvent the program: how to avoid the risk or its impact on the project to minimize
Note: risk associated with additional notes and tips
Enterprise Java projects through careful study, this paper J2EE project process is divided into the following stages:
Provider choice: at the beginning of your J2EE project before, to choose the most appropriate provider, from the application server to the development tools, has been to enjoy a coffee during the vendor.
Design: In a series of strict compliance with the norms and methods of software engineering premise, you can start the design of fully enough, then it is natural to enter the development stage. In the development prior to thoughtfully consider what is being done better and how to do down the problem. Also, I use a number of design templates to be sure to enter the development even before the thought of all the problems and possible solutions. However, sometimes I also do some coding of the stage, and sometimes this can answer some questions, to effectively determine the performance and module division on the issue.
Development: that is, program development stage, select some good development tools to perform sophisticated design, etc., at this stage will show its superiority, and can be of great help to developers.
Stability / load testing: In this stage, the system architects and project managers should freeze the live product characteristics, and focus on quality and product parameters (number of concurrent users allowed, failure recovery, etc). Quality and performance at this stage should be given adequate attention. Of course, it is best to avoid the first stage should be slow to write bad code and to the stage to virtuemart template a lot of changes.
Maturity: This is not a real phase of the project, but a fixed stage of preparation. Potential errors in the past (from the poor design and development, the wrong vendor selection) may occur and affect your system.
OK, the following us into the top 10 project risk!
-------------------------------------------------- ------------------------------
Risk 1: There is no real understanding of Java, EJB, and J2EE
This problem can be decomposed into three parts for analysis.
Description: There is no real understanding of Java
Project Phase: Development
Of stages: design, stability testing, maturity
The impact on system performance: maintainability, scalability, perprestashopmance
Symptoms:
Repeat the development of the core API features in the JDK or class
Do not know how some of the items in the following list (this is just some practical examples of the theme or only):
Garbage collector (train, generational, incremental, synchronous, asynchronous)
When an object can be garbage collected - dangling references
Inheritance mechanism and use the balance
over-riding prestashop over-loading method
Why is java.lang.String (used here instead of your favorite class) for the poor performance
Java in the pass-by reference semantics and value of EJB in the semantics of pass-by comparison
Use == or use equals () method for nonprimitives
Java threads on different platforms running sequential manner (for example, whether a preemptive approach)
New thread and compare the local thread
Hotspot technology (and why the old Hotspot performance tuning optimization technology to reduce the effect of)
JIT, JIT and when good things are going bad (not installed JAVA compiler, and you get just enough code to run well)
API to collect
RMI
Circumvent the program:
You need to constantly improve the knowledge of Java, especially in-depth understanding of Java's strengths and weaknesses. Java has far more than the existence of the value of a language, understanding platform (JDK and tools, etc.) is also important. Specifically, you should be certified Java programmer, if you are not, perhaps you sometimes do not know as there are so many surprised by the content. In addition, you can join the Java mailing list. I had previously joined each such company to join the mailing list, learn from peer technology, it will be your best resource.
Note:
If you or your team members do not really understand the programming language and platform, how can you maintain a hope of success it? Strong dry EJB and Java programmers is to J2EE, like a duck is to water. In contrast, relatively weak, inexperienced programmers can develop poor quality J2EE applications.
Description: There is no real understanding of EJB
Project Stage:
Design
Of stages:
Development, stabilization
Impact on the system:
Maintenance
Symptoms:
EJB is called after the first no longer be used (especially the stateless session bean)
No re-use value of the EJB
Developers do not understand what to do, what the container to provide
Does not follow the EJB specification defines the (fire thread, load the local library, trying to perform I / O, etc.)
Solution:
To improve the knowledge about EJB, you can find a weekend to read the EJB specification (version 1.1 of 314 pages), then read the 2.0 specification (524 pages!), So you can not understand the definition of 1.1 to 2.0 specification in the supplementary content. EJB developers from the beginning to read chapter 18.1 and 18.2 is more appropriate.
Note:
From the provider's point of view not to EJB, to know exactly what standards are supported by EJB specification models and special applications based on these models the difference between. This will also help you migrate to another provider when used.
Description: There is no real understanding of J2EE
Project Stage:
Design
Of stages:
Development
Impact on the system:
Maintenance, scalability, performance
Symptoms:
Management replaced by hand container - provides a mechanism
The safe handling of the custom mode - J2EE platform in the enterprise computing, from the presentation logic to the background process, has been integrated with the most complete security architecture; but rarely use the full functionality.
Solution:
Learning the key components of J2EE and understand their advantages and disadvantages of each alternative in turn use them as a service;
Note:
Only knowledge can compensate for these problems. Good Java EJB developers will be a good developer, has since attained a master should become J2EE. Java and J2EE knowledge to master the more, the design and development work will be more outstanding. Everything will be orderly at the design stage.
-------------------------------------------------- ------------------------------
Risk 2: over-design (Over-engineering) (using EJB or not to use EJB)
Project Stage:
Design
Stage of the project:
Development
Impact on the system:
Maintenance, scalability, performance
Symptoms:
Too large EJB
EJB developers can not explain what to do, and the connection between the
Can not re-use of the EJB, components or services
EJB starts a new transaction, and the transaction of the of the existing EJB from a start
For security, separation of the data set too high a level
Solution:
Over-engineered solutions directly from the Extreme Programming (XP) Methods: The minimum design and programming to meet the demand, and for no it dry. Unless you need to clearly know the possible future needs, such as the future load requirements, or the system's performance at the highest load, or no need for the system to do too much to consider in future cases or speculation. In addition, J2EE platform has defined the scalability and error recovery feature, allowing you to handle server system.
In the smallest system contains only one small components that do one thing, as long as the do to achieve these requirements, system stability has been improved, and that the maintainability of your system will become very strong in the future to increase functionality to meet the new demand will also become easier.
Note:
Apart from the above listed programs, you can implement design patterns - they can significantly improve your system design. EJB model itself is also widely used design pattern. For example, each EJB Home interface is carried by the Finder and the Factory pattern instance. EJB's remote interface to play a practical implementation of the proxy bean, and the capacity for the provision of container is also essential, these containers, such as the interception of call signals and provides clear (transparent) load balancing service. Neglected part of design patterns is also dangerous.
I have virtuemart template mentioned the need to oppose another danger: only for use with EJB EJB. In your application may not need a certain part of EJB, or even your entire application does not need. This is over-engineered are moving in the extreme, but I do have seen some good servlet and JavaBean application was reconstructed for the EJB, but this does no good technical reasons.
-------------------------------------------------- ------------------------------
Risk 3: Not the form of business rules and logic separation
Project Stage:
Design
Stage of the project:
Development
Impact on the system:
Maintenance, scalability, perprestashopmance
Symptoms:
Too large, not marginal JSP program
Time for a change in the business logic must be modified JSP
In calling for a change when the need to modify the interface display and re-configure the EJB, and other background components
Circumvent the program:
J2EE platform allows you the opportunity to express separation of logic and navigation control, and then with the separation of business rules. This is called mode 2 structure.
Note:
You can use a consistent user interface framework designed for the connection. (For example, can use the taglib), which will help you avoid the problem of separation logic. There are many good options available for ready-made. Were assessed for each, and then use the most appropriate framework.
-------------------------------------------------- ------------------------------
Risk 4: There is no appropriate in the development environment configuration
Project Stage:
Development
Stage of the project:
Stabilization, concurrent, mature
Impact on the system:
Your balance
Symptoms:
After several days or weeks of time to transition to a mature system
Risk exists with the transition period, with many uncertainties, some of the major features scenes have not been tested to
Data and the actual system development, testing, data from different
Can not be formed on the developer machine
Application behavior in the development, stability, and production environment of different
Circumvent the program:
The solution is faithful in the development environment to configure the actual environment for the development of the products with the environment close to the implementation of the environment. If the future of the environment is JDK 1.2.2 and Solaris 7, so do not JDK 1.3 and Red Hat Linux on development. The application server used as well. Similarly, to quickly see the product data in the database, and such data for testing. Do not rely on manually created data. If the product data is very sensitive, then virtuemart template that they are not sensitive to, and then configure it up. Development not expected to produce product data will be destroyed following procedure:
Data validation rules
System testing behavior
Construction of system components (in particular, including: EJB-EJB and EJB-database)
The worst is that this may also result in an exception, null pointer, and you've never seen a problem.
Note:
Developers virtuemart template put the security issue to begin addressing the stabilization stage. To prevent this trap generation, you can spend as much time in the business logic to improve security.
Maturity is a complex process, which is full of technical problems and non-technical issues. You may be caught in a lot of unexpected problems, which is implied by all mature. Development and stability of environmental processes to provide you with the issue of making more of these, and the discovery of such problem areas, continue to do it, can greatly reduce the risk.
The more work you do, the more you understand what is feasible and what is not feasible. You can record the engineering issues in order to avoid the same mistakes repeated.
-------------------------------------------------- ------------------------------
Risk 5: choose the wrong provider
Project Stage:
Provider of choice
Of stages:
Design, development, stability / load testing, mature
Impact on the system:
Scalability, performance, maintainability and stability
Symptoms:
Developers more time to use the tools to deal with the problem, not very effective use of these tools
To cope with the problems of known and unknown, and had to re-design of the system significantly
Between the different tools is difficult to be integrated (application server and IDE tools, IDE tools and debuggers, source control and synthesis tools, etc.)
For the IDE and debugger and other tools, developers tend to marginalize them, and respected their favorite tools
Circumvent the program:
To avoid prestashop risk of 5, you need a good provider selection process, to avoid the risk of 10 also apply here.
The true measure of an IDE tool is the most appropriate way is to actually use it. The only to evaluate a J2EE application is to create a concept test to be proved in the experiment to include your application framework. In fact, you do not want to spend time for 3 months after the training and development in the use of Shiyou found some bug.
Assuming that half of the time in prestashop development, suddenly found a problem with your set of tools, then you should have known that some tools are more important than others do. If your chosen application server can not fully meet your needs, you have to modify the original settings. If the IDE is not good, you need to set the minimum code standards, prestashop allows developers to choose the most effective tool they think.
Note:
To really understand where a supplier on a specific task would be best, in fact, the decision is not a one-time thing. You need to keep track and assess the market. prestashop example, in the past year I have used 4 different IDE tools, depending on what I use the application server platform, such as whether to use EJB.
-------------------------------------------------- ------------------------------
Risk 6: do not know your provider
Project Stage:
Provider of choice
Of stages:
Providers at all stages of the selection phase followed: the design, development, stability / load testing, mature
Impact on the system:
Maintainability, scalability, performance,
Symptoms:
Used in the development cycle than the worst forecasts of cycle 1 / 3
Provider has already provided a feature, but the developers do not know the circumstances of the re-development of the functional
Circumvent the program:
In order to avoid such risks, you can subscribe to as much as possible provider of online resources, such as mailing lists, newsgroups, version information (in particular the description of bug fixes, etc.), you will reap the harvest as many immeasurable .
Once you have selected the provider, then we should immediately invest in training and as much as possible before the start time for the project. Then, gradually build the team's understanding and trust this provider. Try to create several EJB and deploy about, then your presentation layer technology (Swing GUI, JSP, etc.) to call them. If you only want to build a development environment, but also in achieving the project objectives, it will produce some unnecessary conflicts. In fact, I have seen the build process has not been the case: Some people would say:
Note:
In the J2EE world, the provider of technical compatibility of products How? Let us look at IBM and BEA's detailed analysis of it. Both are in their respective application server supports EJB 1.1. So, in fact, BEA WebLogic 5.1 and IBM WebSphere 3.5 How many similarities do?
BEA WebLogic and IBM WebSphere system configuration and management is almost completely different.
IBM WebSphere used in a full GUI environment, as opposed to the, BEA WebLogic provides a set in the command line.
IBM WebSphere and CORBA with IIOP to communicate exceptions, these abnormalities are visible on the programmer; WebLogic no CORBA structure, while the default is to use t3 protocol.
WebSphere and Visual Age convergence close, and WebLogic are IDE independent, in fact, you almost can use any development tools.
Thus, the difference is considerable. If you are an expert application server does not mean that you are all experts in the application server. This distinction reflected in the IDE, debugger, build tools, configuration management, and so on. A provider with experience in the use of a special tool, you can evaluate the product provider's competitors have some convenience. But do not expect seamlessly between different products in the transfer or convergence. Therefore, you have to spend enough time mastering these tools.
-------------------------------------------------- ------------------------------
Risk 7: The design does not fully take into account scalability and performance
Project Stage:
Design
Phase of the project affected:
Development, load testing and mature
Impact on the system:
Scalability, performance, maintainability
Symptoms:
Can not stand the slow pace of
System to increase the burden of the server, but can not use to some clustering technology.
Circumvent the program:
To focus on the performance and scalability needs, specifically the development of performance indicators to be achieved. If you need 50 transactions per second, and your EJB design can only provide 40, then you need to consider alternatives, such as stored procedures, batch, or to reconsider the design of OLTP.
Providers as possible to join you, they should be very aware of their products, where the strengths and weak in, and then give you the most direct help.
Note:
The risk and risk 2 (over-engineering) there seems to conflict. In fact, the two affect each other. 2 shows the risk of my solution is only in the circumstances absolutely necessary to build. While with the performance and scalability, you have to divide well in advance what must be done.
If you implement the system needs to recognize the very strong scalability, and use it as a more critical needs, you first need to select a cluster with strong support and transactional application server cache. In addition, you should design business objects EJB, which can take full advantage of server architecture advantages. XP no problem, you are still only absolutely necessary work.
I view this as a check and balance approach. We only need the simplest possible system, the system only provides the customer needs to function and behavior.
-------------------------------------------------- ------------------------------
Risk 8:
old development process
Project Stage:
Development
Of stages:
Stabilization, mature
Impact on the system:
Maintainability, and code quality
Symptoms:
Project seems similar to the waterfall model:
Since there are no build (build) process, each building is like a nightmare
Construction of the date of the loss is equal to the date of the development, because nothing made
There is no difference in the integrated components before being fully tested, and integration testing means that the two volatile components together, and then view the stack trace results.
Circumvent the program:
Good software methodology will improve the life of your software. XP approach I have mentioned previously, you can find a lot of information in this regard.
Note:
JUnit can be used for unit testing, Ant tool to compile and build, these 2 tools are on the XP method has very good support.
-------------------------------------------------- ------------------------------
Risk 9: there is no good way to structure
Project Stage:
Development
Of stages:
Development, stabilization, maturity
Impact on the system:
Maintainability, scalability, code quality
Symptoms:
Used in the code many times found in the core libraries Bug.
Not established the log standard - so the system output is difficult to read or parse.
Poor exception handling inconsistent. In some sites, we can even see an error message directly exposed to the end user, for example, the user's shopping cart in his account to send a nuclear SQLException stack trace information, the user will then how? Call to the database administrator requirements primary key constraint on the patch do?
The following tasks have been handled in various ways the developer numerous times, these are necessary for any structure on the design of the first targets.
Log
Exception Handling
Connect with the resources (database, name services, etc.)
Building JSP Pages
Data validity check
Circumvent prestashop program:
I am a light methodology believers and practitioners. My first article on JavaWorld - Even if you have already started to develop, and then consider the structure is still worthwhile. Maybe you had to endure to bring about reconstruction of the exception handling and log processing, but still worth the long term, so that save time and money.
Note:
Let us think about the framework of component-based development in the reusability of the different levels. The first level is the plumbing, with a ratio of 0.9 or more reusable, ie, 90% of the project can reuse it. The more detailed service definition, the lower the proportion of reuse. In other words, I need to build an accounting service, but to provide the management and usage of these resources, so that the other 50% of the project can reuse them. But for those projects, to get those resources, then it is great!
-------------------------------------------------- ------------------------------
Risk 10: project planning and design of market-based effects, prestashop out of technical reality
Note: there have been new to Java / EJB development areas, the number of people do not understand Java but also more general than expected.
Project Stage:
Will be affected at all stages, including choice of provider
Of stages:
All stages are affected
Impact on the system:
Maintainability, scalability, design quality, code quality
Symptoms:
Technical decisions lightly, that the EJB only for the convenience of a portable processing
Choose a provider of products, when the trial is not immediately
The life cycle of the project also need to replace the tool
Circumvent the program:
Do not believe anyone outside the project's view, these people may already have some vested interest, do not believe providers say (unless you already know), do not believe the White Paper. If you want to get from the real world recommendations on the application server, you can get access. You can also download these tools to assess, with them to do some prototype, and run about one of the sample. (Providers have such a good example).
Overall, the project for you to choose the best providers and tools takes time, and you may not have much time. You can limit the choice of objects in the 3-4, and then a week to compare and test. Satisfied with the final to choose the tools and products.
Note:
If you lack experience in J2EE, it may cause problems in the project early on. In the pre-determined decision-making will affect the whole process, thus affecting the success of the project. Good J2EE consultants will be able to help you choose a good provider, and for the design and development carved out a good configuration.
-------------------------------------------------- ------------------------------
Only the 10 risk just do?
10 is only a particular number, obviously, there are more and more risk exists. But I can guarantee is that if you set out to overcome the risks, then your project will have outstanding performance and has laid the foundation of success.
There is also a need to pay attention, that there can be no substitute for experience and plans. If you have no experience, then it must find a way to obtain and accumulation. Do not train while doing side projects. Before the development of well prepared in advance, it is best to prepare in the design before. Allow your team to accept the guidance of Java/J2EE consultants and to ensure that such guidance can be passed to the other team members.
Finally, there is need to refer to the following:
Outside of software engineering
When unit testing, integration testing when?
Design patterns
Exception Handling
Conclusion
Overall, more than 10 major risk is that your Java projects in enterprise development will face major difficulties. I also believe in your journey there must be more of a trap, but I am more convinced that the risks I have mentioned already covered the main issues. Finally, let us re-listed according to priority risk about 10:
Did not really understand Java, did not really understand EJB, J2EE
did not really understand
Over-design (Over-engineering)
Not the form of business rules and logic separation
Not appropriate in prestashop development environment configuration
Choose the wrong provider
Do not know your provider
Does not fully take into account the design and performance scalability
Old development
There is no good way to structure
Project planning and design of market-based effects, and out of technical reality
Finally, let me wish you good luck!