I have a list of items which I want to run an executor service to perform some expensive action: Say I have 100 items in the list, I expect the es to performExpensiveAction on all 100 items but it only performs the action on 10 items. Answer You should consider using invokeAll instead shutdown. The shutdown()…
Is it possible to define PlanningVariables programmatically (at runtime) instead of through annotations?
Honestly, I haven’t tried much as I must have completely missed (or failed to recognize) the relevant sections in the docs. Here is why I’m asking: I have a working domain model for a given optimization. I can use the domain for a very similar optimization while changing the PlanningVariable. Inst…
How to use Java reduce() function on stream of objects with BinaryOperator
combinedResult is a stream of type ObjectNode that consists of data like this for example: I want to get a result like this: I have written the below BinaryOperator function But when I try this out, I get below result: I understand that this is because I return o1 as default value in the BinaryOperator, but I…
Access Denied – Unable to authenticate login – spring security
I work on simple authentication app using spring security & encounter by an access denied error. I must mention that registration works perfectly & I’ve already created 1 record with bcrypted password but on login I’m failed to understand that what did I miss. Grateful for the help User.ja…
PSQLException: ERROR: syntax error at or near “.”
I’m using Java 8, Spring Boot, and PostgreSQL. I have the following query and it is giving me an error PSQLException: ERROR: syntax error at or near “.” I can’t seem to figure out what is causing this. It does not appear to be any reserved words. Edit So I turned on debug logs and got …
Android recycle view update sort list with concurrency issue
I have a sorted list I would like to use to hold objects for maintaining a recycleview as usual. The api I am interfacing with passes me updates through an interface callback using multiple threads. This api can add, remove or update object state. When the app opens there is a flurry of adds, removes and upda…
Exception in thread “main” org.hibernate.AnnotationException: – Use of @OneToMany or @ManyToMany targeting an unmapped class:
Java 11 Try to use Hibernate Here migration sql: Here entities: And one more And try run like this: But I get error: Answer The problem is in this block: You either use @Column or a@One/ManyToOne/Many relation. You cannot use both. The first one is for mapping primitive data types. The other one is for entiti…
How to set log4j 2.x output path after reading in log4j.xml
Say I have an appender defined in the log4j.xml file below. How could I change the value “/home/logs/oarm_log.txt” to a different value that comes from a string found in the actual Java code so that the code determines where to output the .txt file? Answer Though your best go-to resource for this …
How to get object field for max value in another field in grouped by one more field?
I have list of entities that looks like this: For each code with max version I wanna to get creationDate. I did it like this, but I think that it can be done somehow easier… Answer You can do like this: After grouping by each code then use collectingAndThen collectors and find max item based on version …
Spring WebClient corrupts binary data
I’m sending files containing binary data from service A to service B. When the number of files is relatively small (let’s say 5) everything works well. However, when I try to send more files (let’s say several hundred) it sometimes fails. I tried to check what is happening with this binary d…