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Java Generics FAQs - Frequently Asked Questions

Java Generics FAQs - Frequently Asked Questions
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Multi-Agent Transport Simulation | MATSim Reflecting generics Code by Any Other NameReflecting genericsby Ian RobertsonJune 23, 2007 Summary Type arguments to generic classes are not available for reflection at runtime - or are they? The type arguments for statically declared types can be discovered at runtime. A look at how to do this, and why you might want to. Probably the most common complaint about generics in Java is that they are not reified - there is not a way to know at runtime that a List<String> is any different from a List<Long>. Super type tokens are a nice trick to distinguish between types which have the same raw type, but different type arguments. UserType is used to provide custom mappings between database values and Java objects. Unfortunately, because of type erasure, the "obvious" implementation of returnedClass() doesn't work. While this works, it does so at the cost of forcing clients to repeat themselves: At first glance, then, it seems that the following ought to do the trick: The next step is a bit more involved.

Factory Chain: A Design Pattern for Factories with Generics by Hugo Troche - developer.*, Developer Dot Star Introduction The recent Java 5 (a.k.a. Java 1.5) generics implementation opens both new problems and new opportunities in the implementation of the "Gang of Four" (GoF) Factory patterns [Gamma, et al 1995]. On the one hand, we want a class factory to determine the type it will instantiate at run time. On the other hand, when we use generics correctly the compiler has to be able to determine the type of any call at compile time; casting with generics is considered unsafe. As we’ll see, these two opposing facts make it cumbersome to implement classic factories with generics. Factories The Factory pattern is powerful. In Figure 1 we have the interface Car. Figure 1. To implement this UML, we need is a class that will return a Car type according to some logic executed at run time. Listing 1. As we can see in ClassicFactory, the type of car that getCar() returns is decided at run time. Generics Object obj = ...; //The compiler will produce a warning for this cast. public class CustomVector Class

Developing an Enterprise Application for Oracle WebLogic Server This tutorial demonstrates how to use the IDE to create a web application that uses JavaServer Faces (JSF) 2.x and the Java Persistence API (JPA) 2.0 and then deploy the application to the Oracle WebLogic Server. In this tutorial you will register the WebLogic Server with the IDE, and then use wizards in the IDE to create a JDBC resource and entity and bean classes. You will then use the IDE to deploy the application to the server and register the new datasource. Contents To follow this tutorial, you need the following software and resources. Notes. This project uses the sample database that is available for either the MySQL or JavaDB database servers. Registering the Oracle WebLogic Server In this tutorial you will deploy a web application to the Oracle WebLogic Server. Downloading and Installing the Server Download the installer from the Oracle WebLogic Server Downloads page. Registering the Server with the IDE Open the Services window. Opening the Admin Console Note. Note. <? Note. Note. <?

java lang specifications Java SE 9 The Java Language Specification, Java SE 9 Edition The Java Virtual Machine Specification, Java SE 9 Edition Java SE 8 The Java Language Specification, Java SE 8 Edition The Java Virtual Machine Specification, Java SE 8 Edition Java SE 7 The Java Language Specification, Java SE 7 Edition The Java Virtual Machine Specification, Java SE 7 Edition HTML | PDF | Update (March 2015) Java SE 6 The Java Language Specification, Third Edition The Java Virtual Machine Specification, Second Edition HTML | Update (SE 5.0) | Update (SE 6) | Update (March 2015) Ten 100-year predictions that came true 11 January 2012Last updated at 00:09 By Tom Geoghegan BBC News Magazine John Watkins predicted Americans would be taller, tanks would exist and C, X and Q would no longer feature in our everyday alphabet In 1900, an American civil engineer called John Elfreth Watkins made a number of predictions about what the world would be like in 2000. How did he do? As is customary at the start of a new year, the media have been full of predictions about what may happen in the months ahead. But a much longer forecast made in 1900 by a relatively unknown engineer has been recirculating in the past few days. In December of that year, at the start of the 20th Century, John Elfreth Watkins wrote a piece published on page eight of an American women's magazine, Ladies' Home Journal, entitled What May Happen in the Next Hundred Years. Watkins was a writer for the Journal's sister magazine, the Saturday Evening Post, based in Indianapolis. It was picked up and caused some excitement on Twitter. 1. 2. 3. 4. 5. 6.

UnboundID LDAP SDK for Java LDAP SDK for Java Getting Started with the UnboundID LDAP SDK for Java The UnboundID LDAP SDK for Java is a powerful, user-friendly, pure Java library for interacting with LDAP directory servers. It contains a full-featured API that may be used to communicate with any LDAPv3 directory server, as well as additional enhanced functionality for performing additional operations when interacting with the UnboundID Directory Server. Standard LDAP Communication Accessing Additional Functionality Featured Downloads LDAP SDK for Java Download now » LDAP SDK for Java (Minimal Edition) Download now » LDAP SDK Documentation Click here » © Copyright 2013. Terms of Use | Privacy | Site Map

An Introduction to Generics in Java > Generic Methods Like generic classes, methods and constructors can also have type parameters. These parameters are declared prior to the return type of the method and can be used as return types, argument types, and in the throws clause. For example, see Listing 4. Listing 4 Generic method—finds max T 1 public <T extends Comparable> T max(T t1, T t2) { 2 if (t1.compareTo(t2) > 0) 3 return t1; 4 else return t2; 5 } Here, the method "max(...)" has a single type parameter "T" declared as "<T extends Comparable>". Listing 5 Clients of generic max method 1 Integer iresult = max(new Integer(100), new Integer(200)); 2 String sresult = max("AA", "BB"); 3 Number nresult = max(new Integer(100), "AAA"); // does not compile Line 1 of Listing 5 shows a typical invocation of our method. Line 2 of Listing 5 demonstrates the same functionality, only this time using a different implementor of Comparable, String. Line 3 of Listing 5 generates the following compiler error:

An Eclipse / GlassFish / Java EE 6 Tutorial » Programming For whatever reason my programming blog got lost in binary space. Because of the popularity of this page, I’ve restored in from a backup. I probably won’t restore the rest of the site though. Version 1.4, last updated May 23, 2011 – 11:10 The content of this tutorial is still relevant, but you may also consider my new open source Azzyzt JEE Tools, a set of Eclipse plugins that greatly simplify the process of creating a Java Enterprise application using the patterns outlined in this tutorial. In “4 – Equipment” I have committed myself to using Eclipse and the Java Enterprise Edition as my tools, while in “5 – Patterns And Languages” I’ve declared my high-level goals for implementing a next step of design pattern-based tools. I am no expert in this field, some important things may be missing, so just take the following as a set of things that work for me. Applicability This is a tutorial about using Eclipse and the GlassFish v3 Java application server to implement Java EE 6 applications. or

scjp notes SCJP2 Study Notes This section contains study notes for the Sun Certified Java 2 Programmer Exam (SCJP2). Usage use the menu on the left to navigate the various Certification Objective pages use the menu on the bottom of the Objective and note pages to navigate notes related to the selected Objective save and compile the to see Java concepts in action are things to be keep in mind when taking the exam are things to watch out for when taking the exam Testing concepts If you're having a problem with a concept, WRITE SOME CODE to test it! !!! Visit JavaRanch on a regular basis! It's site on the Web if you want to learn everything and anything about Java! Pick up a good certification study guide. Best of luck in your studies!

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