I have URL for user dashboard(/users/{userId}). I wanted to support /users/current for current logged user, and I searched for ways to implement that, and I did that by the following code. However, I think it’s too overwhelming and I wonder if there are better/simpler ways to do that. P. S. I think I ma…
Tag: java
Java JPA SpringBoot
I have table A and table B, table B have a fk that rererences to table A. class EntityA class EntityB But when i try to call findAll method from repository (from EntityA) i get: Could not write JSON: Infinite recursion Answer I’ve solved the problem using unidirectional relationship. Used this on my Ent…
Nested Autowired Dependencies not injected in Junits
Below is the code to demonstrate the issue. Class3 has autowired field Class2 and Class2 has autowired dependency of Class1, simpleTest to get the String value of Class1 using Class3. So in the test execution Class2 is not null and gets injected into Class3, but Class1 is null in Class2. Answer That’s b…
Byte array to string conversion
I’m making an Android app that communicates with bluetooth device. I’m writing a specific message to chosen characteristic as follows: My conversion function looks like this: I’m trying to figure out why in this case my conversion output looks like this: D/uploadDataset: Message: �����������…
Setting up multi-release JAR unit tests
I have a project that uses a lot of reflection, also on “new” Java features such as records and sealed classes. I’m writing a class like this: Of course, this only works in Java 16 and higher, so I’m trying to set up a multi-release JAR file, with a default implementation like this: I&…
Java – code will always throw a Null Pointer Exception when no Property is present?
I have inherited the following java code, that gets the value of a property from a properties file: The intended behavior in the above flow is that personName will either be retrieved from the properties file or will be returned as null if its not there, and handled accordingly. However when the property is n…
How to bundle a JAR file with its dependencies using maven
I am developing a Java agent using ByteBuddy, and I need the ByteBuddy library .jar file to be included in the agent .jar file. So far, in order for the agent to run smoothly, I need the ByteBuddy library .jar files to be present in the classpath both at compile time and at runtime. How can I bundle a .jar
Cannot load a thread that loads chart from JFreeChart until clicked
I think I did everything right. All I want is to load the thread that contains chart after the main thread that loads the components and window is finished. But it didn’t work. Somehow I have to click jPanel1 (the panel that will load the chart) and the chart is loaded. Any help would be appreciated. Wh…
Stream API – how to return map of unique task name – average result?
I have a CourseResult class Here is my method signature I need to return an average result of every task. Answer I’d flatMap that stream to a stream of the taskResults’ entries, and then use Collectors.averagingDouble to get the average per task:
NamedQuery returning entities with null fields
defined entity with namedquery as SELECT mdl FROM tbl_slots mdl where mdl.test_date between :dt and :dt order by mdl.test_time asc if used * instead of mdl in query, JPA gives error unexpected token: * if mentioned the column names in select statement it returns entities with respective fields populated with …