Java Fundamentals: The Java Reflection API Method Handles

By Jose Paumard
The Reflection API brings class and object introspection to Java, on top of which Spring and Hibernate are built. This course covers object creation, field modification, and method invocation, as well as Method and Var handles for improved performances.
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Course info
Rating
(15)
Level
Intermediate
Updated
Jan 18, 2019
Duration
3h 10m
Table of contents
Course Overview
Course Overview 2m
Introducing Java Reflection
Introduction to the Course, What Are You Going to Learn? 3m Who Are You? What Should You Know to Follow This Course? 1m Agenda of the Course 2m Agenda of This Module 1m Introducing the Java Reflection API: Class, Field, and Method 2m Introducing the Class Named Class, Getting an Instance of Class 2m Getting a Class Instance Using the Object.getClass() Method 3m Getting a Class Instance from the Name of the Class 3m Wrapping up the Three Patterns to Get a Class Object 1m Getting the Super Class and the Implemented Interfaces of a Class 2m Getting the Declared and Non Declared Fields of a Class 4m Getting the Methods and the Constructors of a Class 3m Reading the Modifier to Tell if a Class Member Is Public 4m Demo: Using the Reflection API to Read Fields and Methods 7m Module Wrap Up 1m
Creating an Object Metamodel Using Annotations and Reflection
Introduction to the Module and Agenda 1m Introducing the Mapping of Objects to Databases, XML, and JSON 1m Creating a Metamodel by Adding Annotations to Fields 2m Using the Reflection API to Read and Write a Field of an Object 4m Making a Field Accessible to Reading from Outside its Class 3m Designing an EntityManager for Reading and Writing to a Database 2m Demo: Designing a Generic Metamodel 3m Demo: Adding Application Specific Annotations to a Bean 2m Demo: Setting the Retention Policy of an Annotation 2m Demo: Implementing the Generic Metamodel 3m Demo: Running the Generic Metamodel 2m Module Wrap Up 1m
Creating an Object Relational Mapper Using an Object Metamodel
Introduction to the Module and Agenda 1m Introducing the Database Server and the Person Bean 2m Demo: Setting up the Project and Its Dependencies 2m Demo: Runnning the H2 Server and Launching SQL Requests 4m Demo: Writing the Pattern to Create and Persist Person Instances 2m Demo: Creating and Implementing the EntityManager Interface 4m Demo: Building the SQL Query to Insert a Person Bean 5m Demo: Preparing the Statement to Execute the Query 4m Demo: Setting the Primary Key Value to the Insert Statement 4m Demo: Setting the Field Values to the Statement 4m Demo: Running the EntityManager to Persist Person Instances 3m Demo: Creating the Find Pattern and the Select Query 3m Demo: Setting the Primary Key Value to the Select Statement 2m Demo: Creating an Instance of the Object Read from the Database 2m Demo: Setting the Primary Key Value to the Object 2m Demo: Setting the Column Values and Reading the Objects 3m Demo: Creating an EntityManager Specific to a Database 3m Demo: Closing Properly the PreparedStatement and ResultSet 1m Demo: Specifying the Mapping through the Annotations 4m Module Wrap Up 2m
Injecting Dependencies in an Object Using an Object Metamodel
Introduction to the Module and Agenda 2m Applying Dependency Inversion Using Dependency Injection 2m Designing an EntityManager Independent of the Database 2m Designing a BeanManager to Perform Dependency Injection 4m Getting and Invoking Methods Using the Reflection API 3m Demo: Preparing the Project for Dependency Injection 2m Demo: Updating the EntityManager with Dependency Injection 3m Demo: Creating the BeanManager to Create the EntityManager 2m Demo: Associating Types to Creation Recipes in the BeanManager 6m Demo: Injecting the Connection Value to Provide the EntityManager 4m Module Wrap Up 1m
Improving Performance Using Method Handles
Introduction to the Module and Agenda 1m Spotting Security Checks While Calling Reflection Code 2m Introducing MethodHandles VarHandle and the Lookup Object 2m Getting a Private Trusted Lookup Object 1m Using a Method Handle to Get a Reference on a Class 1m Creating MethodType Object to Get a Reference on a Method 3m Getting a Method Handle on a Method or a Constructor 2m Getting a Method Handle to Read and Write a Field 3m Using a Method Handle to Invoke a Method of a Class 2m Accessing Public and Private Fields Using Method Handles 5m Adding Concurrent Field Access Using the VarHandle API 2m Using VarHandle to Gain Concurrent Access to Fields 2m Demo: Creating Person Beans Using Method Handles on Constructors 4m Demo: Invoking Methods Using Method Handles 2m Demo: Reading and Writing Private Fields Using Method Handles 3m Course Wrap Up 3m
Description
Course info
Rating
(15)
Level
Intermediate
Updated
Jan 18, 2019
Duration
3h 10m
Description

As a Java developer, mastering the reflection API allows you to build powerful frameworks that will bring advanced functionalities to your application. In this course, Java Fundamentals: The Java Reflection API Method Handles, you will learn how you can use reflection API efficiently. This API is very technical, so this course is organized around the study of two real-life use cases: the building of an Object Relational Mapper, on the model of Hibernate, and the creation of a dependency injection framework, on the model of Spring. First, you will understand how to introspect classes and objects and how to discover their structure. Next, you will learn how to build objects without knowing their class at compile time, to set values to their fields and to invoke their methods. Finally, you will understand the performance issues of this API, and be able to use method handles and var handles to fix these issues. By the end of this course, you will be able to master the reflection API that will help you in creating performant and versatile Java applications.

About the author
Jose Paumard
About the author

Passionate about programming computers for over 20 years, Jose made his debut in assembler and C, C for SIMD parallel machines before adopting Java as an object-oriented language. Assistant professor in Paris North University for more than 15 years, Jose also brings his expertise to many projects, in various industrial fields.

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Section Introduction Transcripts
Section Introduction Transcripts

Course Overview
Hello, my name is Jose. I'm a Java Champion and Java Rockstar. I'm talking to you from Paris, and I'm very excited to present my new course, Java Fundamentals: The Java Reflection API and Method Handles. This course shows you how to discover the structure of classes at runtime without knowing them at compile time. You will learn how to create objects; how to set up their fields, even private fields; how to invoke their methods; how to use annotations to add metadata on class elements; and how to read them at runtime. Method handles are also covered for improved performances. I organized this course around two very important real-life use cases. First, you will create a simple object relational mapper on the model of Hibernate, and second, a spring-like dependency injection framework. Before you move on, be sure to be familiar with all these, the Java language, a little bit of lambdas, and the basics of SQL databases and JDBC. The Reflection API is not an easy topic. It is very technical. And I can't wait to see the awesome tools and applications you will be writing after following this course.

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