Tutorial by Examples: in

Instantiating sun.misc.Unsafe via bootclasspath

public class UnsafeLoader { public static Unsafe loadUnsafe() { return Unsafe.getUnsafe(); } } While this example will compile, it is likely to fail at runtime unless the Unsafe class was loaded with the primary classloader. To ensure that happens the JVM should be loaded with...

Java Language • sun.misc.Unsafe

Check for existence before dropping

MySQL3.19 DROP TABLE IF EXISTS MyTable; PostgreSQL8.x DROP TABLE IF EXISTS MyTable; SQL Server2005 If Exists(Select * From Information_Schema.Tables Where Table_Schema = 'dbo' And Table_Name = 'MyTable') Drop Table dbo.MyTable SQLite3.0 DROP TABLE IF EXI...

SQL • DROP Table

Installation or Setup

Microsoft describes 3 ways of installing WinDbg: as part of the WDK (Windows Driver Kit) as part of the SDK (Software Development Kit) with the installer of the SDK and deselecting everything else but "Debugging Tools for Windows" To get the installer, visit Download the WDK, WinDb...

WinDbg • Getting started with WinDbg

Pitfall - Unnecessary use of Primitive Wrappers can lead to NullPointerExceptions

Sometimes, programmers who are new Java will use primitive types and wrappers interchangeably. This can lead to problems. Consider this example: public class MyRecord { public int a, b; public Integer c, d; } ... MyRecord record = new MyRecord(); record.a = 1; // OK ...

Java Language • Java Pitfalls - Nulls and NullPointerException

Multidex by using MultiDexApplication directly

Use this option if you don't need an Application subclass. This is the simplest option, but this way you can't provide your own Application subclass. If an Application subclass is needed, you will have to switch to one of the other options to do so. For this option, simply specify the fully-quali...

Android • Multidex and the Dex Method Limit

Multidex by extending Application

Use this option if your project requires an Application subclass. Specify this Application subclass using the android:name property in the manifest file inside the application tag. In the Application subclass, add the attachBaseContext() method override, and in that method call MultiDex.install():...

Android • Multidex and the Dex Method Limit

ReactJS component written in Typescript

You can use ReactJS's components easily in TypeScript. Just rename the 'jsx' file extension to 'tsx': //helloMessage.tsx: var HelloMessage = React.createClass({ render: function() { return <div>Hello {this.props.name}</div>; } }); ReactDOM.render(<HelloMessage name=&q...

TypeScript • Using Typescript with React (JS & native)

Inline with



            
            
If a sentence contains computer code (for example, the name of an HTML element), use the code element to mark it up:
&lt;p&gt;The &lt;code&gt;a&lt;/code&gt; element creates a hyperlink.&lt;/p&gt;


            

            
            
                
                    
                        HTML
                        •
                        Marking up computer code





    

        

            
            
                
                    Not matching a given string
                
            

            
            
To match something that does not contain a given string, one can use negative lookahead:
Regex syntax: (?!string-to-not-match)
Example:
//not matching &quot;popcorn&quot;
String regexString = &quot;^(?!popcorn).*$&quot;;
System.out.println(&quot;[popcorn] &quot; + (&quot;popcorn&quot;.matches(r...            

            
            
                
                    
                        Java Language
                        •
                        Regular Expressions
                        
                    
                    
                
            
        
    




    

        

            
            
                
                    Integration Tests
                
            

            
            
lib.rs:
pub fn to_test(output: bool) -&gt; bool {
    output
}

Each file in the tests/ folder is compiled as single crate.
tests/integration_test.rs
extern crate test_lib;
use test_lib::to_test;

#[test]
fn test_to_test(){
    assert_eq!(to_test(true), true);
}


            

            
            
                
                    
                        Rust
                        •
                        Tests
                        
                    
                    
                
            
        
    




    

        

            
            
                
                    Custom string interpolators
                
            

            
            
It is possible to define custom string interpolators in addition to the built-in ones.
my&quot;foo${bar}baz&quot;

Is expanded by the compiler to:
new scala.StringContext(&quot;foo&quot;, &quot;baz&quot;).my(bar)

scala.StringContext has no my method, therefore it can be provided by implicit c...            

            
            
                
                    
                        Scala Language
                        •
                        String Interpolation
                        
                    
                    
                
            
        
    




    

        

            
            
                
                    Using a Template Engine
                
            

            
            
Using a Template Engine
The following code will setup Jade as template engine. (Note: Jade has been renamed to pug as of December 2015.)
const express = require('express');  //Imports the express module
const app = express();  //Creates an instance of the express module

const PORT = 3000; //Ra...            

            
            
                
                    
                        Node.js
                        •
                        Web Apps With Express
                        
                    
                    
                
            
        
    




    

        

            
            
                
                    Databinding in Fragment
                
            

            
            
Data Model
public class Item {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name){
        this.name = name;
    }

}

Layout XML
&lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
&lt;layout xmlns:an...            

            
            
                
                    
                        Android
                        •
                        Data Binding Library
                        
                    
                    
                
            
        
    




    

        

            
            
                
                    Parsing JSON property to enum with Gson
                
            

            
            
If you want to parse a String to enum with Gson:

{&quot;status&quot; : &quot;open&quot;}

public enum Status {
    @SerializedName(&quot;open&quot;)
    OPEN,
    @SerializedName(&quot;waiting&quot;)
    WAITING,
    @SerializedName(&quot;confirm&quot;)
    CONFIRM,
    @SerializedName(&...            

            
            
                
                    
                        Android
                        •
                        Gson
                        
                    
                    
                
            
        
    




    

        

            
            
                
                    Show Size of All Tables in Current Database 
                
            

            
            
SELECT
    s.name + '.' + t.NAME AS TableName,
    SUM(a.used_pages)*8 AS 'TableSizeKB'  --a page in SQL Server is 8kb
FROM sys.tables t
    JOIN sys.schemas s on t.schema_id = s.schema_id
    LEFT JOIN sys.indexes i ON t.OBJECT_ID = i.object_id
    LEFT JOIN sys.partitions p ON i.object_id = ...            

            
            
                
                    
                        Microsoft SQL Server
                        •
                        Retrieve information about the database
                        
                    
                    
                
            
        
    




    

        

            
            
                
                    Installation or Setup
                
            

            
            
Since JUnit is a Java library, all you have to do to install it is to add a few JAR files into the classpath of your Java project and you're ready to go.
You can download these two JAR files manually: junit.jar &amp; hamcrest-core.jar.
If you're using Maven, you can simply add in a dependency into...            

            
            
                
                    
                        junit
                        •
                        Getting started with junit
                        
                    
                    
                
            
        
    




    

        

            
            
                
                    Caller info attributes
                
            

            
            
Caller info attributes can be used to pass down information about the invoker to the invoked method. The declaration looks like this:
using System.Runtime.CompilerServices;

public void LogException(Exception ex,
                         [CallerMemberName]string callerMemberName = &quot;&quot;,
...            

            
            
                
                    
                        C# Language
                        •
                        Attributes
                        
                    
                    
                
            
        
    




    

        

            
            
                
                    Converting to boolean
                
            

            
            
Boolean(...) will convert any data type into either true or false.
Boolean(&quot;true&quot;) === true
Boolean(&quot;false&quot;) === true
Boolean(-1) === true
Boolean(1) === true
Boolean(0) === false
Boolean(&quot;&quot;) === false
Boolean(&quot;1&quot;) === true
Boolean(&quot;0&quot;) === t...            

            
            
                
                    
                        JavaScript
                        •
                        Variable coercion/conversion
                        
                    
                    
                
            
        
    




    

        

            
            
                
                    Define primary, primary dark, and accent colors
                
            

            
            
You can customize your theme’s color palette.
Using framework APIs
5.0
&lt;style name=&quot;AppTheme&quot; parent=&quot;Theme.Material&quot;&gt;
    &lt;item name=&quot;android:colorPrimary&quot;&gt;@color/primary&lt;/item&gt;
    &lt;item name=&quot;android:colorPrimaryDark&quot;&gt;@color/pri...            

            
            
                
                    
                        Android
                        •
                        Theme, Style, Attribute
                        
                    
                    
                
            
        
    




    

        

            
            
                
                    Installation
                
            

            
            
Have required JavaScript and CSS files included in your index.html. You can do this by either using the CDN files availiable at the following paths:
&lt;link rel=&quot;stylesheet&quot; type=&quot;text/css&quot; href=&quot;//cdn.datatables.net/1.10.12/css/jquery.dataTables.css&quot;&gt;
  
&lt;scr...            

            
            
                
                    
                        datatables
                        •
                        Getting started with datatables