Tutorial by Examples: g

public static Unsafe getUnsafe() { try { Field unsafe = Unsafe.class.getDeclaredField("theUnsafe"); unsafe.setAccessible(true); return (Unsafe) unsafe.get(null); } catch (IllegalAccessException e) { // Handle } catch (IllegalArgumentExcept...

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...

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...

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...

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():...

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

lib.rs: pub fn to_test(output: bool) -> 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); }

When you do a groupby you can select either a single column or a list of columns: In [11]: df = pd.DataFrame([[1, 1, 2], [1, 2, 3], [2, 3, 4]], columns=["A", "B", "C"]) In [12]: df Out[12]: A B C 0 1 1 2 1 1 2 3 2 2 3 4 In [13]: g = df.groupby(...

It is possible to define custom string interpolators in addition to the built-in ones. my"foo${bar}baz" Is expanded by the compiler to: new scala.StringContext("foo", "baz").my(bar) scala.StringContext has no my method, therefore it can be provided by implicit c...

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...

Data Model public class Item { private String name; public String getName() { return name; } public void setName(String name){ this.name = name; } } Layout XML <?xml version="1.0" encoding="utf-8"?> <layout xmlns:an...

If you want to parse a String to enum with Gson: {"status" : "open"} public enum Status { @SerializedName("open") OPEN, @SerializedName("waiting") WAITING, @SerializedName("confirm") CONFIRM, @SerializedName(&...

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

In themes.xml: <style name="AppTheme" parent="Theme.AppCompat"> <!-- Theme attributes here --> </style> In AndroidManifest.xml: <application android:icon="@mipmap/ic_launcher" android:label="@string/app_name" andr...

XML elements often nest, have data in attributes and/or as character data. The way to capture this data is by using ,attr and ,chardata respectively for those cases. var doc = ` <parent> <child1 attr1="attribute one"/> <child2>and some cdata</child2> </p...

The primary task of the manifest is to inform the system about the app's components. For example, a manifest file can declare an activity as follows: <?xml version="1.0" encoding="utf-8"?> <manifest ... > <application android:icon="@drawable/app_icon.pn...

Using the Android API 23 or higher, very often such situation can be seen: This situation is caused by the structural change of the Android API regarding getting the resources. Now the function: public int getColor(@ColorRes int id, @Nullable Theme theme) throws NotFoundException should ...

package main import ( "log" "sync" "time" ) func main() { // The WaitGroup lets the main goroutine wait for all other goroutines // to terminate. However, this is no implicit in Go. The WaitGroup must // be explicitely incremented pr...

package main import ( "fmt" "time" ) // The pinger prints a ping and waits for a pong func pinger(pinger <-chan int, ponger chan<- int) { for { <-pinger fmt.Println("ping") time.Sleep(time.Second) ponge...

/** * Created by Alex Sullivan on 7/21/16. */ public class Foo implements Parcelable { private final int myFirstVariable; private final String mySecondVariable; private final long myThirdVariable; public Foo(int myFirstVariable, String mySecondVariable, long myThirdVariab...