JAVA core and an introduction to Spring Fundamentals

Java 语言特性

• Static typing
• Object oriented （Encapsulation, Inheritance, Polymorphism）
• Based on JVM

JVM

• JVM Memory
  • Heap
  • Stack
• Garbage Collection(GC)
  • Automatic memory management
  • Mark & Sweep
• JVM languages
  • Scala
  • Groovy

JDK & JRE

• JDK

  A superset of a JRE and contaiins tools for JAVA programmers such as javac commpiler ，Jconsole

• JRE

  It includes a JVM implementation together with an implementation of the JAVA Class Library

JDK Packages

• Java.util.concurrent

JAVA Fundamentals

• Interface
• Class
• Accessor
• Annotation

JAVA多线程

• Two basic ways(comparison)
  • Implements runnable interface
  • Extends Thread class
• Synchronized methods and statements

Immutable Objects

• why use Immutable Object
  • When an object is considered immutable if its state cannnot change after it is constructed, like weibo post
• example