static-block

Why can't we set the value of static final variable in static block through class name [duplicate]

泪湿孤枕 提交于 2019-12-03 08:33:56
问题 This question already has answers here : Why isn't a qualified static final variable allowed in a static initialization block? (2 answers) Closed 4 years ago . For example, consider code snap below: public static final int a; public static final int b; static { a = 8; // it's working Test.b = 10; // compilation error Test.b cannot be assigned. } Why can't we use Test.b = 10; inside a static block of the Test class itself? Without the class name it's working fine. Is there any reason behind

Mocking Static Blocks in Java

為{幸葍}努か 提交于 2019-12-02 16:53:29
My motto for Java is "just because Java has static blocks, it doesn't mean that you should be using them." Jokes aside, there are a lot of tricks in Java that make testing a nightmare. Two of the most I hate are Anonymous Classes and Static Blocks. We have a lot of legacy code that make use of Static Blocks and these are one of the annoying points in our push in writing unit tests. Our goal is to be able to write unit tests for classes that depend on this static initialization with minimal code changes. So far my suggestion to my colleagues is to move the body of the static block into a

What is static block in c or c++? [duplicate]

守給你的承諾、 提交于 2019-12-01 16:34:01
This question already has an answer here: What's the C++ idiom equivalent to the Java static block? 6 answers I want to know that what is static block in c or c++ with an example? I know what is static but what is the difference between static and static block? Another alternative is that you might be looking for the analogy of a static block in Java. A block of code that is run when the application is loaded. There is no such thing in C++ but it can be faked by using the constructor of a static object. foo.cpp: struct StaticBlock { StaticBlock(){ cout << "hello" << endl; } } static

How to pass parameter with block form contents from cms pages in magento

拥有回忆 提交于 2019-11-30 18:14:23
I want to pass a variable with the block code like of JSON type in magento, {{block type="multibanners/multibanners" category_id="9" name="multibanners" alias="multibanners" template="multibanners/multibanners.phtml"}} from cms pages content area , but I don't receive any thing. If I use block with action method than I easily get my value. Anyone know how can I pass variable with my custom block? Renon Stewart I'm not 100% sure what you are asking, but if you are trying to pass a variable to multibanners.phtml from the code above then you could create another attribute similar to category_id=

How to pass parameter with block form contents from cms pages in magento

我只是一个虾纸丫 提交于 2019-11-30 02:34:35
问题 I want to pass a variable with the block code like of JSON type in magento, {{block type="multibanners/multibanners" category_id="9" name="multibanners" alias="multibanners" template="multibanners/multibanners.phtml"}} from cms pages content area , but I don't receive any thing. If I use block with action method than I easily get my value. Anyone know how can I pass variable with my custom block? 回答1: I'm not 100% sure what you are asking, but if you are trying to pass a variable to

Enums - static and instance blocks

最后都变了- 提交于 2019-11-28 20:15:29
I had learned that in Java the static block gets executed when the class is initialized and instance block get executed before the construction of each instance of the class . I had always seen the static block to execute before the instance block . Why the case is opposite for enums ? Can anyone please explain me the output of the sample code : enum CoffeeSize { BIG(8), LARGE(10),HUGE(12),OVERWHELMING(); private int ounces ; static { System.out.println("static block "); } { System.out.println("instance block"); } private CoffeeSize(int ounces){ this.ounces = ounces; System.out.println(ounces)

why static block in child class does not get executed?

99封情书 提交于 2019-11-28 05:12:51
问题 here is the code public class ClassResolution { static class Parent { public static String name; static { System.out.println("this is Parent"); name = "Parent"; } } static class Child extends Parent { static { System.out.println("this is Child"); name = "Child"; } } public static void main(String[] args) throws ClassNotFoundException { System.out.println(Child.name); }} what ouput i expect is: this is Parent this is Child Child but actually is: this is Parent Parent it seems static block in

How to initialize ThreadLocal objects in Java

别来无恙 提交于 2019-11-27 22:48:10
I'm having an issue where I'm creating a ThreadLocal and initializing it with new ThreadLocal . The problem is, I really conceptually just want a persistent list that lasts the life of the thread, but I don't know if there's a way to initialize something per-thread in Java. E.g. what I want is something like: ThreadLocal static { myThreadLocalVariable.set(new ArrayList<Whatever>()); } So that it initializes it for every thread. I know I can do this: private static Whatever getMyVariable() { Whatever w = myThreadLocalVariable.get(); if(w == null) { w = new ArrayList<Whatever>();

What does “When a Class is loaded” actually mean?

牧云@^-^@ 提交于 2019-11-27 14:42:13
问题 It is said that static blocks in java run only once when that class is loaded. But what does it actually mean? At which point is a class loaded by JVM (Java Virtual Machine)? Is it when the main method in that class is called? And is it that all the super-classes of the same class are also loaded when the main method starts execution? Consider that A extends B and B extends C. All have static blocks. If A has the main method, then what will be the sequence of execution of static blocks? 回答1:

Behavior of static blocks with inheritance

删除回忆录丶 提交于 2019-11-27 12:39:18
I am trying to use static blocks like this: I have a base class called Base.java public class Base { static public int myVar; } And a derived class Derived.java : public class Derived extends Base { static { Base.myVar = 10; } } My main function is like this: public static void main(String[] args) { System.out.println(Derived.myVar); System.out.println(Base.myVar); } This prints the out put as 0 0 where as I expected 10 0 . Can somebody explain this behavior? Also, if I want my derived classes to set the values for a static variable how can I achieve that? Nikita Beloglazov As I understand.