MongoDB for Node.js Developers

Posted on 2018-01-22 Edited on 2018-02-25 In Information Technology Disqus:

MongDB version 3.6

all the materials

Week 1 Introduction

JavaSE passing data among methods

Posted on 2018-01-21 In Information Technology Disqus:

Basic

In this topic, the most important thing is to make primitive and reference value clear.

JavaSE float double

Posted on 2018-01-21 In Information Technology Disqus:

In Java, default floating type is double.
For example, 3.25 is double rather than float unless f is added to the end of 3.25, i.e. 3.25f.

JavaSE encapsulation & immutability

Posted on 2018-01-20 Edited on 2018-01-21 In Information Technology Disqus:

Encapsulation

Encapsulation refers to preventing callers from changing the instance variables directly.

JavaSE constructor

Posted on 2018-01-20 Edited on 2018-01-21 In Information Technology Disqus:

Default Constructor

default constructor = default non-arguments constructor = Java-created constructor

JavaSE static

Posted on 2018-01-20 Edited on 2018-01-21 In Information Technology Disqus:

Where to use key word static?

method
field

public class Koala{
	public static int count = 0;   // static variable
	public static void main(String[] args){  // static method
		System.out.println(count);
	}
}

public class KoalaTester{
	public static void main(String[] args){
		Koala.main(new String[0]);
	}
}

JavaSE varargs

Posted on 2018-01-20 Edited on 2018-01-21 In Information Technology Disqus:

There are several things to be remembered in this topic.

JavaSE method

Posted on 2018-01-20 Edited on 2018-01-26 In Information Technology Disqus:

Write Methods

What is a method like?

method-signature

Element	Value in nap() example	Required?
Access modifier	public	no
Optional specifier	final	no
Return type	void	yes
Method name	nap	yes
Parameter list	(int minutes)	yes(can be empty)
Optional exception list	throws InterruptedException	no
Method body	{ // take a nap }	yes(can be empty braces)

JavaSE local vs instance variables

Posted on 2018-01-20 In Information Technology Disqus:

Local Variable

A local variable is defined within a method.

JavaSE import

Posted on 2018-01-19 Edited on 2018-01-21 In Information Technology Disqus:

package aquarium; 
public class Water { 
	boolean salty = false; 
} 

package aquarium.jellies; 
public class Water { 
	boolean salty = true; 
} 

package employee; 
INSERT IMPORTS HERE 
public class WaterFiller { 
	Water water; 
}