Effective Java 2nd Edition May 2008 3000th Release.pdf

[khacpv]

I'm reading the book, that I've planned 1 year ago. Each day, I should read an item in the book..
I really want to become a full-stack developer in 2 years from now (2015/03/26). Now I'm sitting on Suwon, Korea.
On 2017/03/26 I will have a place.

[khacpv]

Item 5: Avoid creating unnecessary objects (2015/03/26)

static methods is faster 6 times methods

[khacpv]

Item 6: Eliminate obsolete object references (2015/03/31)

set Null when unreachable
use WeakHashMap or ThreadPoolExcutor

[khacpv]

7.Avoid finalizers (2015/03/31)

finalizer is slower than simple object 430 times

[khacpv]

Item 8: Obey the general contract when overriding equals (2015/03/31)

Equal:

_Reflexive_ x.equals(x) = true
_Symmetric: x.equals(y) = true <=> y.equal(x) = true
_Transitive: x.equals(y) = true AND y.equals(z) = true => x.equals(z) = true
_Consistent_: x.equals(y) = true IF !change(x or y)
x!=null => x.equals(null) = false

[khacpv]

Item 9: Always override hashCode when you override equals

HashMap, HashSet, HashTable