Java

When building Spring Boot applications, handling concurrent API calls efficiently is crucial to ensure optimal performance and scalability. Here are a few approaches to manage concurrent read and write operations: Handling Concurrent Read API Calls Asynchronous Methods Using @Async at @Service annotation and enabling asynchronous processing can help handle multiple API calls concurrently. @Async public CompletableFuture<String> asyncMethod() { // Call external API return CompletableFuture.completedFuture("Result"); } WebClient with Reactor Spring WebFlux’s WebClient allows for reactive programming, making it easier to handle multiple API calls. ...

“Load balancing” can be explained as maintaining any workload. For example if you have to serve 1000 breakfast in the morning you can divide the work among 2-3 or more caterers to lower the delivery/preparation time. In the computer world, same logic applies, if you want to deliver fast, you can divide the work, for example for a website we can have 5-10 webserver, this way website will be delivered faster(especially during high traffic), this is server side. ...

Spring boot is the most famous java framework, and I have been looking for a simple way to serve a java app on a hosting service(not dedicated which is very expensive not AWS/Azure which are too complicated), Most shared hosting does not support java apps, they support php or asp or perl here is the table for godaddy webhosting supported tech. I will explain how to deploy from dockerhub to Koyeb, or we can deploy from github repository too. ...

I was thinking on this question How does HashMap handle collisions internally? What changes were introduced in Java 8 for its implementation? and reading this blog says On a final note, from Java 8, the linked lists are dynamically replaced with balanced binary search trees in collision resolution after the number of collisions in a given bucket location exceed a certain threshold. Than I wonder how it works and went and found the source code of hash map in openjdk. It is a very long class, almost 2600 lines, but so many comments 🤓 it is not very common to see this much comment in a java code, anyway then I start reading it and wanted to note down how it behaves on collusion ...

FFM is the new API trying to replace JNI and jep is here It is basically calling functions outside of JVM or accessing memory not managed by JVM. I wanted to test can FFM beat regular Java API, below you can find a simple test doing math sin with FFM and with regular Math.sin import java.lang.foreign.FunctionDescriptor; import java.lang.foreign.Linker; import java.lang.foreign.MemorySegment; import java.lang.foreign.SymbolLookup; import java.lang.foreign.ValueLayout; public class FFMSinTest { public static void main(String[] args) throws Throwable { Linker linker = Linker.nativeLinker(); SymbolLookup stdlib = linker.defaultLookup(); // Locate the "sin" function in the C math library MemorySegment sinAddress = stdlib.find("sin").orElseThrow(); FunctionDescriptor descriptor = FunctionDescriptor.of(ValueLayout.JAVA_DOUBLE, ValueLayout.JAVA_DOUBLE); var sinHandle = linker.downcallHandle(sinAddress, descriptor); double angle = Math.PI / 4; // 45 degrees in radians // Timing Java's Math.sin() long javaStartTime = System.nanoTime(); for (int i = 0; i < 1_000_000; i++) { double result = Math.sin(angle); } long javaEndTime = System.nanoTime(); long javaDuration = javaEndTime - javaStartTime; // Timing C sin via FFM long ffmStartTime = System.nanoTime(); for (int i = 0; i < 1_000_000; i++) { double result = (double) sinHandle.invoke(angle); } long ffmEndTime = System.nanoTime(); long ffmDuration = ffmEndTime - ffmStartTime; System.out.println("Java Math.sin() took: " + javaDuration / 1_000_000.0 + " ms"); System.out.println("C sin (FFM) took: " + ffmDuration / 1_000_000.0 + " ms"); } } And result is ...