static-block

Why static block is not executed

由 孤街醉人 提交于 2019-12-10 15:58:09
问题 As per java doc, static block is executed when the class is initialized. Could anyone please tell me why static block is not executed when I run below code? class A { static { System.out.println("Static Block"); } } public class Main { public static void example1() { Class<?> class1 = A.class; System.out.println(class1); } public static void example2() { try { Class<?> class1 = Class.forName("ClassLoading_Interview_Example.ex1.A"); System.out.println(class1); }catch(Exception e) { e

When objects created with static reference, why do instance block & default constructor get executed before static block?

由 和自甴很熟 提交于 2019-12-08 19:39:35
问题 public class TestLab { static Test aStatic=new Test(); public static void main(String[] args) { TestLab obj=new TestLab(); } static{ System.out.println("In static block of TestLab"); } } public class Test { static Test ref=new Test(); Test() { System.out.println("Default Constructor of Test"); } static { System.out.println("In Static Block of Test"); } { System.out.println("In instance block of Test"); } } Normally the static blocks are executed first during class loading. When the above

static block vs initializer block vs constructor in inheritance [duplicate]

由 余生长醉 提交于 2019-12-08 19:09:32
This question already has answers here : Use of Initializers vs Constructors in Java (9 answers) Closed 5 years ago . i find this example and i want to understand the logic behind it ? how constructors and static blocks and initializer blocks works in inheritance ? in which stage each one is called ? public class Parent { static { System.out.println("i am Parent 3"); } { System.out.println("i am parent 2"); } public Parent() { System.out.println("i am parent 1"); } } public class Son extends Parent { static {System.out.println("i am son 3");} {System.out.println("i am son 2");} public Son() {

static block vs initializer block vs constructor in inheritance [duplicate]

由 扶醉桌前 提交于 2019-12-08 05:28:54
问题 This question already has answers here : Use of Initializers vs Constructors in Java (9 answers) Closed 5 years ago . i find this example and i want to understand the logic behind it ? how constructors and static blocks and initializer blocks works in inheritance ? in which stage each one is called ? public class Parent { static { System.out.println("i am Parent 3"); } { System.out.println("i am parent 2"); } public Parent() { System.out.println("i am parent 1"); } } public class Son extends

Singleton object- In static block or in getInstance(); which should be used

由 穿精又带淫゛_ 提交于 2019-12-07 03:25:14
问题 Below are two ways to implement a singleton. What are the advantages and disadvantages of each? Static initialization: class Singleton { private Singleton instance; static { instance = new Singleton(); } public Singleton getInstance() { return instance; } } Lazy initialization is: class Singleton { private Singleton instance; public Singleton getInstance(){ if (instance == null) instance = new Singleton(); return instance; } } 回答1: Synchronized Accessor public class Singleton { private static

When linking, is there something between “grab what you need” and “grab all” (-Wl,--whole-archive)?

由 假装没事ソ 提交于 2019-12-05 10:50:10
I have this library which involves some static initialization code which needs to run before main() . It all works well if you just compile all of the translation units together, but it doesn't work if I provide a static library ( .a file) and have users link their application against it - the linker simply ignores the symbols which do my static initialization. Alternatively, I can make the linker pick up everything in the static library, if I specify the -Wl,--whole-archive option to GCC, i.e. specify the --whole-archive option to GNU link. But is there some middle ground? Can I mark some

Singleton object- In static block or in getInstance(); which should be used

由 我的未来我决定 提交于 2019-12-05 06:20:10
Below are two ways to implement a singleton. What are the advantages and disadvantages of each? Static initialization: class Singleton { private Singleton instance; static { instance = new Singleton(); } public Singleton getInstance() { return instance; } } Lazy initialization is: class Singleton { private Singleton instance; public Singleton getInstance(){ if (instance == null) instance = new Singleton(); return instance; } } Alexander Synchronized Accessor public class Singleton { private static Singleton instance; public static synchronized Singleton getInstance() { if (instance == null) {

Can static code blocks throw exceptions? [duplicate]

由 浪尽此生 提交于 2019-12-05 03:50:50
This question already has an answer here: Why doesn't Java allow to throw a checked exception from static initialization block? 8 answers In a hypothetical situation I have a class like this: import java.io.File; import java.util.Scanner; class X { static Scanner scanner; static { scanner = new Scanner(new File("X.txt")); } } When compiling, I get unreported exeption java.io.FileNotFoundException ; must be caught or declared to be thrown because public Scanner(File source) throws FileNotFoundException . To fix this, I can put scanner = new... line in a try/catch statement: static { try {

Magento How to link to category by id from static block/page

由 拥有回忆 提交于 2019-12-05 00:07:50
问题 I'm looking to link to a category from a static block using the category id . Any thoughts? I've done the usual searches, but to no avail. At the moment I can do something like <a href="{{store url="category-i-want.html"}}"> , but this is hardly robust. 回答1: Use the category link widget inline link code: {{widget type="catalog/category_widget_link" anchor_text="Displayed Text" title="Title attribute text" template="catalog/category/widget/link/link_block.phtml" id_path="category/22"}} 来源：

Add <style> and <script> in Magento static block

由 送分小仙女□ 提交于 2019-12-04 19:03:17
I have a static block (Identifier is mega_menu ) It has some code like this: <ul class="dropdown-menu" role="menu"> <li data-submenu-id="submenu-patas"> <div id="submenu-patas" class="popover"> <h3 class="popover-title">Patas</h3> <div class="popover-content"><img src="img/patas.png"></div> </div> </li> <li data-submenu-id="submenu-snub-nosed"> <div id="submenu-snub-nosed" class="popover"> <h3 class="popover-title">Golden Snub-Nosed</h3> <div class="popover-content"><img src="img/snub-nosed.png"></div> </div> </li> </ul> In the normal html file (from where I got this code) there are some
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