JavaDocs JavaDocs is able to easily generate a code “maintenance manual” A doc comment is made up of two parts – a description and two or more tag. /** * Here is description * * @tag Comment for tag */ Tags @author (classes and interfaces only, required) @version (classes and interfaces only, required) @param (methods and constructors only) @return (methods only) @exception @see @since @serial (or @serialField or @serialData) @deprecated JDK Docs External documentation can be created with javadoc

Class & Object A class only exists at compile time; An object only exists at runtime. Data Encapsulation Data Encapsulation/information hiding: where the internal state and operation are hidden from others. The more information Class A knows about Class B, the greater the possibility that changing Class A will adversely affect Class B. In an ideal world, making internal changes to Class A should have no, or very little, effect on other classes.

Basic types Every type have a default value: Type Representation Initial value Storage Max. value byte singed integer 0 8 bits 127 short singed integer 0 16 bits 32767 int singed integer 0 32 bits 2147483647 long singed integer 0 64 bits over 10^18 float floating point 0.0 32 bits over 10^38 double floating point 0.0 64 bits over 10^308 boolean true or false false 1 bit char UNICODE (not ASCII) u0000 16 bits uFFFF Difference between i++ and ++i b = 1; a = b++; // a = 1; b = 2 b = 1; a = ++b; // a = 2; b = 2 int a = 1; int res = a++ + a; // res = 3 ; a = 2.

This is learning note for MarkDown Heading 1 or Heading 1 Heading 2 or Heading 2 Italic and bold italic or italic bold or bold italic and bold or italic and bold Unordered list line 1 line 2 line 3 sub 1 sub 2 or line 1 line 2 line 3 sub 1 sub 2 Ordered list line 1 line 2 sub 1 sub 2 line 3 BlockQuotes Use ‘>’ for a quotes

You’ll find this post in your _posts directory. Go ahead and edit it and re-build the site to see your changes. You can rebuild the site in many different ways, but the most common way is to run jekyll serve, which launches a web server and auto-regenerates your site when a file is updated. To add new posts, simply add a file in the _posts directory that follows the convention YYYY-MM-DD-name-of-post.

Synchronous & asynchronous Function run synchronously means code is running as same as your writing. But in real situation, some code may need time to running (like fetch). If synchronously run all code, program will be block and wait this time consuming part finish and continue. In the most of the time, You code logic need wait to continue but you don’t want to block all progress. Maybe UI rendering or some other total unrelated code.