When I use Jackson polymorphic serialization, it generates a JSON object with an incorrect fully qualified class name. The code below serializes an XMLGregorianCalendar. The output is: I expected the following: Why does it output java.util.GregorianCalendar? Or more importantly: How do I fix this? Code exampl…
confusion about upcasting vs dynamic binding
So I am having some confusion understanding dynamic binding vs upcasting. My original understanding was that when you create a base_class reference and assign it to a derived class object like: you can now call the methods/member functions of derived_class with obj.method_of_derived class(), without dynamic b…
Is there anyway to get the size of the text in a JTextArea?
The title pretty much says it all. What I don’t mean is how to get the size of the JTextArea. I need to get the size of the actual text. I am completely open to suggestions though. If you have a wonky workaround that involves using something other than JTextArea but still has a similar effect, I’d…
401 instead of 403 with Spring Boot 2
With Spring Boot 1.5.6.RELEASE I was able to send HTTP Status code 401 instead of 403 as described in How let spring security response unauthorized(http 401 code) if requesting uri without authentication, by doing this: using the org.springframework.boot.autoconfigure.security.Http401AuthenticationEntryPoint …
this pointer escape in Java
When reading < Java Concurrency in Practice >, there’s an example saying that the following code snippet will lead to this pointer escape in the constructor method. But I’m not sure what exactly does it mean, since I couldn’t see any this reference in the source code of ThisEscape cons…
Does JVM Stack have no direct references to objects but reference to constant pool?
I am investigating JVM architecture and its working behind the scenes. I have heard a lot of times that stack stores method return types, operands, local variables and references to objects. But while reading the Oracle specification I have found the picture where drawn that stack frame has no references to o…
Dispatcher servlet startup error- ConfigurableWebApplicationContext.APPLICATION_CONTEXT_ID_PREFIX and existence of multiple context warning
I get these two exceptions successively when I start my application on websphere application server. 1- 2- my web.xml is like below. Part of my pom file is like below: I read that this error may be due to any depencency mismatch. I tried several versions but I couldn’t fix it. I will be very happy if yo…
Set JRE to use Windows trust store, specifically the user’s trust store
Summary: Java option -Djavax.net.ssl.trustStoreType=WINDOWS-ROOT allows Java to use the Windows trust store for the computer account. What option allows it to use the Windows trust store for the user account? We have a Java application that we run on our Windows clients. The application gets data from various…
How can I mask a hexadecimal int using Java?
I have an integer that contains a hexa value. I want to extract the first characters from this hexa value like it was a String value but I don’t want to convert it to a String. In my case I can’t use String utilities like substring. Answer It’s important to understand that an integer is just…
disable-infobars argument unable to hide the infobar with the message “Chrome is being controlled by automated test software” with ChromeDriver v2.36
I just updated ChromeDriver to newest version – 2.36. In previous versions I’ve set: and the “Chrome is being controlled by automated test software” warning bar wasn’t displayed. With the same option set, I’m keep seeing it. Do you know how to disable this from appearing in…