Spring’s @Autowire can be configured such that Spring will not throw an error if no matching autowire candidates are found: @Autowire(required=false) Is there an equivalent JSR-330 annotation? @Inject always fails if there is no matching candidate. Is there any way I can use @Inject but not have the fra…
Why are 2 Long variables not equal with == operator in Java?
I got a very strange problem when I’m trying to compare 2 Long variables, they always show false and I can be sure they have the same number value by debugging in Eclipse: Both of above 2 return values are object-type Long, which confused me. And to verify that I wrote a main method like this: It prints…
java codility Frog-River-One
I have been trying to solve a Java exercise on a Codility web page. Below is the link to the mentioned exercise and my solution. https://codility.com/demo/results/demoH5GMV3-PV8 Can anyone tell what can I correct in my code in order to improve the score? Just in case here is the task description: A small frog…
org.glassfish.jersey.internal.RuntimeDelegateImpl NOT FOUND
I am using jersey for my project and tring to parse a URI from a string. The code is simple, but I get a error below It seems the program can not find the delegate. I already imported javax.ws.rs.core.UriBuilder and have jersey-common 2.0 that should contain the delegate in my build path. But I still get this…
How to write a function that can calculate power in Java. No loops
I’ve been trying to write a simple function in Java that can calculate a number to the nth power without using loops. I then found the Math.pow(a, b) class… or method still can’t distinguish the two am not so good with theory. So i wrote this.. Then i wanted to make my own Math.pow without u…
Partition a Set into smaller Subsets and process as batch
I have a continuous running thread in my application, which consists of a HashSet to store all the symbols inside the application. As per the design at the time it was written, inside the thread’s while true condition it will iterate the HashSet continuously, and update the database for all the symbols …
How to initialize and draw a Rectangle variable in a paintComponent method? [closed]
I’ve been trying to add collision to my game, it seemed like a piece of cake, I already know how to draw a rectangle. But I need that rectangle to be represented by something, a variable. But it seems …
Setter methods or constructors
so far I have seen two approaches of setting a variable’s value in Java. Sometimes a constructor with arguments is used, others setter methods are used to set the value of each variable. I know that a constructor initialises an instance variable inside a class once a class is instantiated using the R…
SEVERE: Context [/example] startup failed due to previous errors
I’m new at Java EE + Spring + Hibernate + Maven combination. Trying to make a simple project with tomcat 6.0. Our project just fine, no problem with debugging. But when i’m trying to run the server, it gives me “Error listenerStart” all the time. I searched all around the web for 3 day…
Getting ‘java.lang.UnsatisfiedLinkError’: no lwjgl in java.library.path
Note this is different from this question because it does not deal with linking because it’s not asking how to link it via the CLI, but the GUI in Eclipse. I have been trying to write a simple program using LWJGL. When I add the library to Eclipse (Kepler 4.3.1 on Windows 7 64bit) and write a program, i…