Bittiger Lesson3

java bittiger fundanmental

Review

Quicksort:In-space, non-stable
Mergesort: not in-space. stable, O(n) extra memory usage
Primitiive Value: Quicksort
Objects: Mergesort (what is being sort is objects' refrence)
<=7 array: Insertion Sort

Class

variables
method
modifier

private/default(package)/protected/public

static--dont need instance

Class -- static

• static class
  
  • static member class
  • non-static member class
• static method
• static variable
• static initializer
• static block(first run)

static member class

class List {
  private static Node{
    Node next;
  }
}

static member class is isolated from enclosing class instance.

non-static member class

Class -- static

• static class : static inner class, isolated from enclosing class instance. (Iterator 和instance有关系）
  List里的Node常用static class
• static method:

Class--final

• Final class: class cannot be extended
• Final method: method cannot be override
• Final variable:variable can only be assigned onve.(Reference!)
  Q:static final variable is immutable?
  Not really. see slides 19.
  final是array（object)的refrence，内存中的refrence不能被改（也不能再new一个array），但array里面的元素(Object里的内容）是可以改的.只有final修饰primitive value才能达到immutable. Guava里的ImmutableList可以做到.
• Finally:finally block -- code section

Interfaces and Abstract Classes

• interface
  
  • Unrelated classes implement your interface.(eg Comparable)
  • Define a new data type. (e.g List)
  • Multiple inheritance types.(e.g List, Deque <== LinkedList)
• Abstract Class
  
  • Share code among classes
  • Share commo non-public methods, variables
  • Share code which coul change the state of the object.

Reflections

if (obj instanceof Objecct) {
   ...
}

Reflection--class