Polina Tishina

Igor Makarov

Java Junior Developer Training Course.

88 hours training + 32 hours work project = 120 hr.

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Introduction to Java and Java Technology (1 hour theory / including 0.5 hour practice)

• Introduction to Java. Benefits.
• JDK, JVM.
• Java 2 (Java EE / SE / ME)
• Tools: java, javac, javadoc

Lab: Installing JDK, Tuning Environmental Variables

• Install JDK from Oracle website
• Set $JAVA_HOME and $PATH

DoD

$ javac -version
$ java -version

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Structure of Java-based applications (3/1)

• Classes and *.class files
• Java app definition
• Classloading
• Classpath
• Packages
• JARs

Lab: developing simple java app

• Main and Printer classes
• Different packages
• One of them in JAR

DoD

Hello, world!

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Development infrastructure: Git (1.5/0.5)

• Intro to GIT
• Repos
• Commits
• Shortly about branches, conflicts and merges

Lab: Setting Up Git

• Install Git and in case of Windows TortoiseGit
• Create account at Github: teamXX
• Fork this repo to your account
• Clone your fork repo locally
• Update README.md locally to your teammates names
• Commit and push initial commit

$ git add .
$ git commit -m “…”
$ git push

DoD

• Trainer see all the forks in github
• Trainer can locate every teammate by its team repo

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Development infrastructure: Maven (1.5/0.5)

• Intro to Maven: build tool and dependency management
• Build lifecycle, goals
• Plugins
• pom.xml
• Dependencies and binary repositories

Demo: Project Creating with Archetype Plugin

Lab: Setting Up Maven

• Install Maven
• Set $M2_HOME
• Analyse our project: tree and pom.xml
• Move your old codebase to this project
• Make it build
• Take your last app under version control and push it

DoD

$ ls teamXX
src README.md pom.xml

$ mvn clean verify
BUILD SUCCESS

$ git add .
$ git commit -m
$ git push

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JetBrains IDEA (1/0.5)

• Opening Maven projects
• Running java apps
• Running maven builds
• Debugging
• Hotkeys
• Git operations

Lab: Installing, the first application compile, run, debugging

• Download and install IDEA with trial corporate license
• Open our maven project
• Change in pom.xml to teamXX
• Build project with maven from IDEA
• Push

DoD

• Trainer can see your team in pom.xml

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Java Syntax for Procedure Style (10/4)

Comments

• Singe and multi-line
• JavaDoc

Procedure style

• Intro to procedure style
• Java Dictionary for naming

Class Method Declaration

• Return type
• Static modifier
• Name
• Parameters
• Static initializers

Variable scopes

• Local variables
• Class variables and methods, static import
• Instance variables and methods: later

Method’s parameters and Overloading

• As local variables
• Method overloading

Primitives

• Primitive variable declaration and initialization
• Primitive types
• Primitive types literal values
• Primitive types casting
• Types Overflow and solution with BigInteger
• FP precision loss and solution with BigDecimal

References

• Reference types in Java
• Reference variables declaration and initialization
• Heap and stack
• Garbage collector

Strings

• String type
• String literal values
• Interning
• String concatenation

Course Project Iteration 01: The Rise of Logger Library

• Read and analyse specification as tests for this iteration in src/test
• Uncomment specification cases
• Implement features needed

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style

Operators

• Arithmetic
• Arithmetic type promotions
• Bitwise
• Logical (lazy and eager)
• Compare and Ternary
• Object references and equality

Controlling execution

• if/switch
• for/do/while/foreach
• Procedure Metrics: CC

Course Project Iteration 02: Logger Library

• Read and analyse specification as tests for this iteration in src/test
• Uncomment specification cases
• Implement features needed

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style

Arrays

• Arrays declaration
• Array literals
• Multi-dimension arrays

Varargs

• Declaration
• Using
• Constraints

Course Project Iteration 03: Logger Library

• Read and analyse specification as tests for this iteration in src/test
• Uncomment specification cases
• Implement features needed

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API

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Procedure style recap (1/0)

• Subject of procedural design
• Reuse
• Procedure generalization
• Inner quality attributes
• Metrics: cyclomatic complexity

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OOAD recap (4/1)

• Programming styles and paradigms
• Procedure style vs OOAD
• Classes and objects
• Inheritance and Delegation as code reuse styles
• Visibility as key for encapsulation
• Polymorphism as key for supportability
• Stateful and stateless design
• Metrics of OOAD: Coupling and Cohesion

Demo: Logger Library Refactoring to OO-Design

• Example Appenders and Filters

Discussion: OOAD benefits for our Logger library and refactorings to do

• FR: presentation changes and sink changes
• Inner NFRs
• Refactorings to do
• Switch and polymorphism and OCP
• Command Design Pattern

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Refactoring with IDEA (1/0)

• Intro to Refactoring
• Basic Refactorings Matrix
• Wrap method / Sprout method

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Java Syntax for OOP (12/4)

Final

• Final modifier semantics: 3

Enums

• Enums emulation with class
• Switch recap
• Smart Enum Pattern

Course Project Iteration 04: Logger Library towards OO through Enums

• FR: presentation changes
• Refactor to Enums: Dumb Commands

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API

Encapsulation

• Encapsulation for packages
• Encapsulation for classes
• Access modifiers

Inheritance

• Inheritance implementation
• Overriding methods
• Overriding constraints

Instatiation

• Constructors
• Object Initializers
• Constructors with inheritance issue

Course Project Iteration 05: Logger Library towards OO through Classes

• FR: presentation changes
• Introduce Facade Design Pattern
• Refactor to Smart Commands with classes

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API

Polymorphism

• Polymorphic collections
• Polymorphic arguments
• Polymorphic algorithms
• Type casting
• Abstract classes
• Template Method pattern
• Strategy/State patterns

Interfaces

• Interface
• Implementation
• Multiple implementation
• Default modifiers for fields and methods
• Static and default (defender) methods

Course Project Iteration 06: OOD Logger Library reached

• FR: presentation changes and sink changes
• Refactor to Polymorphic Commands and Appenders

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API

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OOD Principles and Patterns (4/2)

OOAD Principles: SOLID

• SRP
• OCP and Abstraction leak issues
• LSP
• ISP
• DIP

Creation Design Patterns

• Creator
• Factory
• DI

Discussion: Logger Library Design meets principles and patterns

• What inner NFR issues do we have now
• What refactorings to do

Course Project Iteration 07: Logger Library testability and supportability reached

• FR: presentation changes and sink changes
• Refactor to DI

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API

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Unit testing with JUnit (6/3)

• Assertions in Java
• Testing scopes
• Unit tests
• Structure of unit test
• Tests and contract
• JUnit
• Hamcrest and FEST-assert
• Test doubles types
• Mockito
• Types of coverage (including permutation)
• Intro to TDD

Course Project Iteration 08: Coverage with Unit Tests

• Cover current components with unit tests
• State what code covered

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API
• Unit tests coverage ≥ 50%
• Permutation coverage ≥ 30%

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Intro to Functional Style (6/3)

• Nested Classes
• Inner classes
• Local classes
• Anonymous classes

Course Project Iteration 09: Introduce Observer/Listener Design Pattern for Appenders extensibility

• Observer
• Implementation with Anonymous classes
• FR: As developer I want easily add new Appenders

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API
• Unit tests coverage ≥ 50%
• Permutation coverage ≥ 30%
• Introduced Observer for supportability

Functional style

• Closures in java
• Lambdas
• Functional Interfaces
• Functional style: state, function composition, declarative, immutability

Course Project Iteration 10: Introducing Filters

• FR: As developer I want filter my messages

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API
• Unit tests coverage ≥ 50%
• Permutation coverage ≥ 30%
• Introduced lambdas for filtering messages

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Error handling with exceptions (4/2)

• Comparison of the exception mechanism to the traditional error-handling mechanism
• Types of exceptions, their handling
• Standard Java exceptions
• Designing exceptions type system

Course Project Iteration 11: Introducing Exceptions

• FR: As developer I want strict contracts and error handling

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API
• Unit tests coverage ≥ 70%
• Permutation coverage ≥ 50%
• Introduced checked exceptions for errors and alternate scenarios

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Generics (2/0.5)

• Generics as design style
• Type safety
• Generic classes
• Generic methods

Demo: Type safety for sorting with anonymous implementation of comparator

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System library (6/2)

• System
• Math
• Object: hc and eq contract, toS
• String, its API. Immutability and interns.
• StringBuffer, StringBuilder
• Wrapper classes
• Autoboxing

Course Project Iteration 12: Logger Library Maturity Grown

• NFR: As a developer I want higher collection performance for messages through non-default eq and hc
• NRF: As a developer I want more polymorphism with toS for messages
• NFR: As a developer I want lower memory consumption through StringB*
• FR: As a developer I want business rules applied to all messages types

log("1", "2");
assertMessageEquals("3")

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API
• Unit tests coverage ≥ 70%

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Collection API (4/1)

• Collection types and implementations
• Iteration over collections
• Comparable and Comparator
• Maps and implementations
• Utility classes Collections and Arrays
• Queues
• Stream API

Course Project Iteration 13: Collections for code reuse

• Choose and state collection interfaces
• Choose and state collection implementations
• Refactor legacy codebase to collections API

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IO (8/3)

• java.io.File
• RandomAccessFile
• Stream classes
• InputStreams and OutputStreams
• Stream chaining
• Readers and Writers

Course Project Iteration 14: Logging to File. Finally!

• FR: As a developer I want messages logged to file as plain text

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API
• Unit tests coverage ≥ 70%

Serialization API

• Serialization API

Networking with TCP/IP

• Network API
• Sockets and ServerSocket API
• Welcome to hell no.1! CAP theorem

Course Project Iteration 15: Remote Logging

• FR: As a developer I want collect logs though many app instances and have centralized log
• Server App

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API
• Unit tests coverage ≥ 70%
• System tests for remote log server

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Multi-threading in Java (8/3)

• Thread definition
• Thread start: 3 options
• Thread management
• Thread states begin
• Priorities
• Daemons
• Thread API
• Blocking operations

Course Project Iteration 16: Parallel LogServer App

• FR: As a developer I want more performance for server app
• NFR: File per Thread

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API
• Unit tests coverage ≥ 70%
• System tests for remote log server

Server IO Design Patterns

• Connector/Acceptor
• Proxy
• Pro-actor
• Handler

Discussion: what patterns do you invent?

Concurrency

• Welcome to hell no.2! Concurrency.
• Thread safety and data race
• Thread synchronization
• synchronized section
• Lock API
• New thread states
• Collections thread safety
• wait() / notify()
• Deadlocks
• Intro to java.util.concurrent

Course Project Iteration 17: Concurrent LogServer App

• FR: As a developer I want more and more performance for server app
• NFR: one file for threads
• NFR: less threads with non-blocking input
• Hints: available() and queues

DoD

• All given specifications runs are green
• Code reuse and minimum code duplication
• Code style
• Documented public API
• Unit tests coverage ≥ 70%
• Load test for remote log server

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Annotations and Reflection API intro (1/0)

• Annotations (0,5/0)
• Purpose of annotations
• Standard annotations
• Custom annotations
• Reflection API overview
• Class loaders
• Class introspection

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Work Project. Session 2 (24/24)

Given

• PM
• Analyst
• Product's FRs and NFRs
• System's internal NFRs
• CI server
• Sonar server
• Teams formed
• Every team's git repo visible to PM and is identifiable

When

• Teams formed
• Every team's git repo visible to PM and is identifiable
• Teams deliver product with six iterations

Then

• PM and Business Customers accept product with six demo sessions

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