I’m talking java language. Variable “this”, when used inside a class, refers to the current instance of that class, which means you cannot use “this” inside a static method. But “super”, when used inside a class, refers to the superclass of that class, not an instance…
Tag: static
Necessity of static block in Java
I found that in Java, there is a feature called static block, which includes code that is executed when a class is first loaded (I don’t understand what ‘loaded’ means, does it mean initialized?). Is …
Difference between Static methods and Instance methods
I was just reading over the text given to me in my textbook and I’m not really sure I understand what it is saying. It’s basically telling me that static methods or class methods include the “modifier” keyword static. But I don’t really know what that means? Could someone please …
What is the use of a private static variable in Java?
If a variable is declared as public static varName;, then I can access it from anywhere as ClassName.varName. I am also aware that static members are shared by all instances of a class and are not reallocated in each instance. Is declaring a variable as private static varName; any different from declaring a v…
An alternative to @Value annotation in static function
It’s not possible to use @Value on a static variable. When I do this, 0 is printed. So what is a good alternative to this? Answer Spring inject noting in static field (by default). So you have two alternatives: (the better one) make the field non static (the ugly hack) add an none static setter which wr…
Java static serialization rules?
I’m working on a save state serialization with a few static methods and fields. I could have sworn though that serialization and static’s caused mayhem. Should I make all static’s transient? And will inflating the calls restore the statics as normal? Answer statics are implicitly transient, …
How can I get a resource content from a static context?
I want to read strings from an xml file before I do much of anything else like setText on widgets, so how can I do that without an activity object to call getResources() on? Answer Create a subclass of Application, for instance public class App extends Application { Set the android:name attribute of your <…
Change private static final field using Java reflection
I have a class with a private static final field that, unfortunately, I need to change it at run-time. Using reflection I get this error: java.lang.IllegalAccessException: Can not set static final boolean field Is there any way to change the value? Answer Assuming no SecurityManager is preventing you from doi…
singleton pattern in java. lazy initialization
1.is there a flaw with the above implementation of the getInstance method? 2.What is the difference between the two implementations.? I have seen a lot of answers on the singleton pattern in stackoverflow but the question I have posted is to know mainly difference of ‘synchronize’ at method and bl…
How to handle a static final field initializer that throws checked exception
I am facing a use case where I would like to declare a static finalfield with an initializer statement that is declared to throw a checked exception. Typically, it’d look like this: The issue I have here is that the ObjectName constructor may throw various checked exceptions, which I don’t care ab…