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The following pages have their detailed tips extracted below
The following detailed tips have been extracted from the raw tips page
J2EE Application server performance (Page last updated April 2001, Added 2001-04-20, Author Misha Davidson, Publisher Java Developers Journal). Tips:
- Use stateless session EJBs to cache and manage infrequently changed data. Update the EJB occasionally.
- Use a dedicated session bean to perform and cache all JNDI lookups in a minimum number of requests.
Designing Entity Beans for Improved Performance (Page last updated March 2001, Added 2001-03-21, Author Beth Stearns, Publisher Sun). Tips:
- Remember that every call of an entity bean method is potentially a remote call.
- Designing with one access method per data attribute should only be used where remote access will not occur, i.e. entities are guaranteed to be in the same container.
- Use a value object which encapsulates all of an entity's data attributes, and which transfers all the data in one network transfer. This may result in large objects being transferred though.
- Group entity bean data attributes in subsets, and use multiple value objects to provide remote access to those subsets.
Paper detailing the "Best Practices for Developing High Performance Web and Enterprise Applications" using IBM's WebSphere. All the tips are generally applicable to servlet/EJB development, as well as other types of server development. (Page last updated September 2000, Added 2001-01-19, Author Harvey W. Gunther, Publisher IBM). Tips:
- Access entity beans from session beans, not from client or servlet code.
- The EJB "remote programming" model always assumes EJB calls are remote, even where this is not so. Where calls are actually local to the same JVM, try to use calling mechanisms that avoid the remote call.
J2EE Performance tuning (Page last updated October 2001, Added 2001-10-22, Author James McGovern, Publisher Java Developers Journal). Tips:
- Always access entity beans from session beans.
- Use local entity beans when beans are co-located in the same JVM.
Design patterns catalog (Page last updated 2001, Added 2002-01-25, Author ?, Publisher Sun). Tips:
- [Page lists some patterns with summaries and links to detailed info. Patterns are: Data Access Object; Fast-Lane Reader; Front Controller; Page-by-Page Iterator; Session Facade; Value Object].
- Use the Data Access Object pattern to decouple business logic from data access logic, allowing for optimizations to be made in how data is managed.
- Use the Fast-Lane Reader pattern to accelerate read-only data access by not using enterprise beans.
- Use the Front Controller pattern to centralize incoming client requests, allowing optimizations to be made in aggregating the resulting view.
- Use the Page-by-Page Iterator pattern to efficiently access a large, remote list by retrieving its elements one sublist of value objects at a time.
- Use the Session Facade pattern to provide a unified, workflow-oriented interface to a set of enterprise beans, thus minimizing client calls to server EJBs.
- Use the Value Object pattern to efficiently transfer remote, fine-grained data by sending a coarse-grained view of the data.
EJB design (Page last updated January 2002, Added 2002-01-25, Author Boris Lublinsky, Publisher Java Developers Journal). Tips:
- Some application server implementations (e.g., WebSphere) automatically convert remote communications to local communications to make them faster.
- Low granularity (i.e. fine-grained) methods in an EJB typically leads to poor performance of the overall system.
- Local interfaces in EJB 2.0 is one attempt to improve overall performance: local interfaces provide for beans in the same container to interact locally without involving RMI.
- The most effective way to improve the overall performance of EJB-based applications is to minimize the amount of method invocations, making the communications overhead negligible compared with the execution time. This can be achieved by implementing coarse-grained methods.
- Entity beans should not be simply mapped to database tables. Treating entity beans as such fine-grained objects which are effectively wrappers on table rows leads to increased network communications and heavier database communications than if entity beans are treated as coarse-grained components.
- For optimal performance, entity beans should be designed to: have large granularity, which usually means they should contain multiple Java classes and support multiple database tables; be associated with a certain amount of persistent data, typically multiple database tables, one of which should define the primary key for the whole bean; support meaningful business methods and encapsulate business rules to access the data.
- Don't use client transactions in the EJB environment since long-running transactions that can cause database lockup.
- Entity beans are transactional resources due to their stateful nature, but application server vendors often rely on the underlying database to lock and resolve access appropriately. Although this approach greatly improves performance, it provides the potential for database lockup.
Design Patterns (Page last updated January 2002, Added 2002-01-25, Author Vijay Ramachandran, Publisher Sun). Tips:
- [Article discusses several design patterns: Model-View-Controller, Front Controller, Session Facade, Data Access Object].
- Use the Front Controller pattern to channel all client requests through a single decision point, which allows the application to be balanced at runtime.
- Use a Session Facade to provide a simple interface to a complex subsystem of enterprise beans, and to reduce network communication requirements.
- Use Data Access Objects to decouple the business logic from the data access logic, allowing data access optimizations to be decoupled from other types of optimizations.
Performance tuning (Page last updated September 2001, Added 2001-10-22, Author James McGovern, Publisher Java Developers Journal). Tips:
Why CMP is better than BMP (Page last updated April 2002, Added 2002-04-26, Author Tyler Jewell, Publisher Weblogic Developers Journal). Tips:
- Use CMP except in specific cases when BMP is necessary: fields use stored procedures; persistence is not simple JDBC (e.g. JDO); One bean maps to multiple tables; non-standard SQL is used.
- CMP can make many optimizations: optimal locking; optimistic transactions; efficient lazy loading; efficiently combining multiple queries to the same table (i.e. multiple beans of the same type can be handled together); optimized multi-row deletion to handle deletion of beans and their dependents.
J2EE design patterns to improve performance (Page last updated June 2001, Added 2001-06-18, Author Daniel H. Steinberg, Publisher JavaWorld). Tips:
- Combine multiple remote calls for state information into one call using a value object to wrap the data (the Value Object pattern, superceded by local interfaces in EJB 2.0).
Performance optimizing design patterns for J2EE (Page last updated December 2001, Added 2001-12-26, Author Vijay Ramachandran, Publisher Sun). Tips:
- For read-only access to a set of data that does not change rapidly, use the Fast Lane Reader pattern which bypasses the EJBs and uses a (possibly non-transactional) data access object which encapsulates access to the data. Use the Fast Lane Reader to read data from the server and display all of them in one shot.
- When you need to access a large remote list of objects, use the Page-by-Page Iterator pattern which sends smaller subsets of the data as requested until the client no longer want any more data. Use the Page-by-Page Iterator to send lists of simple objects from EJBs to clients.
- When the client would request many small data items which would require many remote calls to satisfy, combine the multiple calls into one call which results in a single Value Object which holds all the data required to be transferred. Use the Value Object to send a single coarse-grained object from the server to the client(s).
Article on recycling resource pools (Page last updated 1998, Added 2000-12-20, Authors Philip Bishop and Nigel Warren, Publisher JavaWorld). Tips:
- Use the builder pattern: break the construction of complex objects into a series simpler Builder objects, and a Director object which combines the Builders to form the complex object. Then you can use Recycler (a type of Director) to replace only the broken parts of the complex object, so reducing the amount of objects that need to be recreated.
EJB performance tips (Page last updated November 2001, Added 2001-12-26, Authors Ravi Kalidindi and Rohini Datla, Publisher PreciseJava). Tips:
- EJB calls are expensive. A method call from the client could cover all the following: get Home reference from the NamingService (one network round trip); get EJB reference (one or two network roundtrips plus remote creation and initialization of Home and EJB objects); call method and return value on EJB object (two or more network rountrips: client-server and [mutliple] server-db; several costly services used such as transactions, persistence, security, etc; multiple serializations and deserializations).
- If you don't need EJB services for an object, use a plain Java object and not an EJB object.
- Use Local interfaces (from EJB2.0) if you deploy both EJB Client and EJB in the same JVM. (For EJB1.1 based applications, some vendors provide pass-by-reference EJB implementations that work like Local interfaces).
- Wrap multiple entity beans in a session bean to change multiple EJB remote calls into one session bean remote call and several local calls (pattern called SessionFacade).
- Cache EJBHome references to avoid JNDI lookup overhead (pattern called ServiceLocator).
- Use the HttpSession object rather than a Stateful session bean to maintain client state.
- Create read-only entity beans for read only operations.
- Combine business logic with the entity bean that holds the data needed for that logic to process.
Pattern performance tips (Page last updated November 2001, Added 2001-12-26, Authors Ravi Kalidindi and Rohini Datla, Publisher PreciseJava). Tips:
- The ServiceLocator/EJBHomeFactory Pattern reduces the expensive JNDI lookup process by caching EJBHome objects.
- The SessionFacade Pattern reduces network calls by combining accesses to multiple Entity beans into one access to the facade object.
- The MessageFacade/ServiceActivator Pattern moves method calls into a separate object which can execute asynchronously.
- The ValueObject Pattern combines remote data into one serializable object, thus reducing the number of network transfers required to access multiple items of remote data.
- The ValueObjectFactory/ValueObjectAssembler Pattern combines remote data from multiple remote objects into one serializable object, thus reducing the number of network transfers required to access multiple items of remote data.
- The ValueListHandler Pattern: avoids using multiple Entity beans to access the database, using Data Access Objects which explicitly query the database; and returns the data to the client in batches (which can be terminated) rather than in one big chunk, according to the Page-by-Page Iterator pattern.
- The CompositeEntity Pattern reduces the number of actual entity beans by wrapping multiple java objects (which could otherwise be Entity beans) into one Entity bean.
Performance chapter (chapter 20) from "Professional JSP 2nd Edition" (Page last updated August 2001, Added 2001-10-22, Author Simon Brown, Robert Burdick, Darko Cokor, Jayson Falkner, Ben Galbraith, RodJohnson, Larry Kim, Casey Kochmer, Thor Kristmundsson, Sing Li, Dan Malks, Mark Nelson, Grant Palmer, Bob Sullivan, Geoff Taylor, John Timney, Sameer Tyagi, Geert Van Damme, Steve Wilkinson, Publisher The Server Side). Tips:
- Static pages are much faster than dynamic pages, where the web server handles static pages separately.
Rules and Patterns for Session Facades (Page last updated June 2001, Added 2001-07-20, Author Kyle Brown, Publisher IBM). Tips:
- Use the Facade pattern, and specifically Value objects, to transfer all the subset of data needed from an entity bean in one transfer.
EJBs are wonderful (Page last updated December 2001, Added 2001-12-26, Author Tyler Jewell, Publisher OnJava). Tips:
- Configure separate deployments for each entity bean for different usage patterns (e.g. typical 85% read-only, 10% read-write, 5% batch update), and partition the presentation layer to use the appropriate corresponding deployment (e.g. read requests use the read-only deployment).
EJB performance tips (Page last updated December 2001, Added 2001-12-26, Author Krishna Kothapalli and Raghava Kothapalli, Publisher JavaPro). Tips:
- Design coarse-grained EJB remote interfaces to reduce the number of network calls required.
Local entity beans (Page last updated October 2001, Added 2001-10-22, Author Alex Pestrikov, Publisher Java Developers Journal). Tips:
- Facade objects (wrappers) allow local entity beans to be called remotely. This pattern incurs very little overhead for remote calls, while at the same time optimizing local calls between local beans which can use local calls.
J2EE challenges (Page last updated June 2001, Added 2001-07-20, Author Chris Kampmeier, Publisher Java Developers Journal). Tips:
- To ensure good performance use experienced J2EE builders and use proven design patterns.
- Consider the impact of session size on performance.
Moving from JSP to EJB (Page last updated June 2001, Added 2001-06-18, Author Patrick Sean Neville, Publisher Java Developers Journal). Tips:
- Entity EJBs should contain aggregate get/set methods that return chunks of data rather than fine-grained get/set methods for individual attributes, to reduce unnecessary database, transactional, and network communication overheads.
- Avoid stateful session beans as they are resource-heavy, since one instance is maintained for each client.
- Consider using a single stateless session bean to provide access to other EJBs (this is a fašade pattern). This optimizes multiple EJB references and calls by keeping them in-process.
Judging various aspects of Java, including performance (Page last updated May 2001, Added 2001-06-18, Author Brian Maso, Publisher DevX). Tips:
- EJBs are slower and more complex than proprietary server implementations when high scalability is not needed.
Clustering for J2EE and Java application servers. Looks at Bluestone Total-e-server, Sybase Enterprise Application Server, SilverStream Application Server, and WebLogic Application Server. (Page last updated February 2001, Added 2001-03-21, Author Abraham Kang, Publisher JavaWorld). Tips:
- To scale the static portions of your Website, add Web servers; to scale the dynamic portions of your site, add application servers.
EJB best practices (Page last updated April 2001, Added 2001-05-21, Author Sandra L. Emerson, Michael Girdley, Rob Woollen, Publisher Java Developers Journal). Tips:
- Don't model a shared cache or any shared resource as a stateful session bean.
- Stateless session beans are easier to scale than stateful session beans. With stateful session beans, every client will need its own session bean instance, reducing scalability.
"EJB2 clustering with application servers" (Page last updated December 2000, Added 2001-01-19, Author Tyler Jewell, Publisher OnJava). Tips:
- [Article discusses multiple independent ways to load balance EJBs]
RMI arguments (Page last updated December 2001, Added 2002-02-22, Author Scott Oaks, Publisher Java Report). Tips:
- Some application servers can automatically pass parameters by reference if the communicating EJBs are in the same JVM. To ensure that this does not break the application, write EJB methods so that they don't modify the parameters passed to them.
Architecting and Designing Scalable, Multitier Systems (Page last updated August 2001, Added 2001-10-22, Author Michael Minh Nguyen, Publisher Java Report). Tips:
- You can use invisible applets in a browser to validate data on the client.
Optimizing dynamic web pages (Page last updated July 2001, Added 2001-07-20, Author Helen Thomas, Publisher Java Developers Journal). Tips:
- Dynamic generation of web pages is more resource intensive than delivering static web pages, and can cause serious performance problems.
Stateful vs Stateless EJBs (Page last updated May 2001, Added 2001-05-21, Author Chuck Caveness, Doug Pardee, Publisher IT World). Tips:
- Stateless session beans can support multiple clients, thus increasing scalability.
Deciding whether EJB is appropriate. (Page last updated September 2001, Added 2001-10-22, Author Ed Roman, Publisher The Server Side). Tips:
- An HTTP layer is not always necessary. Connecting directly to EJBs is faster and provides automatic load balancing.
Last Updated: 2021-08-29
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