That’s pretty easy: Note that I didn’t either make the methods themselves synchronized or synchronize on this. I firmly believe that it’s a good idea to only acquire locks on objects which only your code has access to, unless you’re deliberately exposing the lock. It makes it a lot easier to reassure yourself that nothing … Read more
You need to follow a few steps to debug properly. 1) mvn clean dependency:tree Take a look at the output to see exactly what you get and verify your dependencies are all there. 2) mvn clean compile. Does this fail? If not does that mean you only get the error in Eclipse? You mentioned in … Read more
You can add a jar in Eclipse by right-clicking on the Project → Build Path → Configure Build Path. Under Libraries tab, click Add Jars or Add External JARs and give the Jar. A quick demo here. The above solution is obviously a “Quick” one. However, if you are working on a project where you need … Read more
You should remove the references to it by assigning null or leaving the block where it was declared. After that, it will be automatically deleted by the garbage collector (not immediately, but eventually). Example 1: Example 2: Not something that you are currently looking for, but FYI: you can invoke the garbage collector with the … Read more
Starting with MySQL 8.0.4, they have changed the default authentication plugin for MySQL server from mysql_native_password to caching_sha2_password. You can run the below command to resolve the issue. sample username / password => student / pass123 Refer the official page for details: MySQL Reference Manual
Java has some controversy about its exceptions. It has two classes of exceptions. Checked and unchecked. Any exception extending from RuntimeException or Error is unchecked and does not need to be caught or explicitly declared as throwable in a method signature. FileNotFound is however a checked exception and must either be caught or declared as … Read more
You are setting the label text before the button is clicked to “txt”. Instead when the button is clicked call setText() on the label and pass it the text from the text field. Example:
Means that these numbers are doubles and floats, respectively. Assume you have and then you call the compiler might be stumped. That’s why you can say 5, 5f, or 5.0 to specify the type.
You can disable jayatana just for the current shell session by unsetting JAVA_TOOL_OPTIONS like so: That way it will still be enabled for applications needing it.
Problem solved, I’ve not added the index.html. Which is point out in the web.xml Note: a project may have more than one web.xml file. if there are another web.xml in src/main/webapp/WEB-INF Then you might need to add another index (this time index.jsp) to src/main/webapp/WEB-INF/pages/