My Python application gradually consumes more memory over time, even though objects should be garbage collected. What causes this leak, and how can I diagnose or fix it?

I'm comparing values in JavaScript and seeing unexpected results—like '0' == 0 returning true, or empty arrays comparing greater than expected. Why does this happen, and which should I use?

I used a loop to register click handlers with a closure variable, but all handlers log the same value instead of each iteration's value. Example: js Copy code for (var i = 0; i < 3; i++) { button.addEventListener('click', function() { con...

When performing operations like 0.1 + 0.2 or multiplying decimals, the results aren’t what I expect. For example: js Copy code console.log(0.1 + 0.2); // 0.30000000000000004 instead of 0.3 Why does this happen, and how should I handle it?

I attached a click handler on a parent container to detect button clicks (event delegation). But sometimes clicking a button triggers multiple handlers unexpectedly—like ancestor handlers or unintended list items. How can I reliably manage this?

I'm running multiple asynchronous calls in an async function. Even though I wrap them in try/catch, some promise rejections still escape and become unhandled.

I have asynchronous code using Promises or async/await, and sometimes errors are not caught—leading to silent failures or warnings such as UnhandledPromiseRejectionWarning. How can I prevent this?

My Java service gradually consumes more heap memory over time, eventually throwing java.lang.OutOfMemoryError: Java heap space. How do I detect and resolve such a memory leak?

In a multithreaded Java program using a shared counter object, the final value after both threads run is often lower than expected (e.g. less than 20000). Why does this happen and how can I fix it?

My Java application throws NullPointerException in surprising places—when calling .length() on a string, unboxing Integer to int, or chaining method calls. Why does this happen and how can I avoid it?

Multiple threads update a shared counter, but the final value doesn't match the expected result. Why does this happen, and how do I fix it?

My code throws a NullPointerException when invoking .equals(...) or calling methods on seemingly non-null objects. How can I prevent this?

My Java application gradually consumes more memory and eventually throws: makefile Copy code java.lang.OutOfMemoryError: Java heap space What commonly causes such memory leaks, and how do I detect and resolve them?

❓ Problem Statement I enabled CORS using Express’s cors() middleware in my Node.js API, but browser errors still say: “No 'Access-Control-Allow-Origin' header is present…”

My Node.js service’s heap usage climbs steadily over time, CPU becomes unresponsive, and eventually crashes with “JavaScript heap out of memory”. How do I detect, debug, and fix such memory leaks?

I’m implementing JWT-based authentication with Node.js (using jsonwebtoken). I frequently encounter errors such as: • JsonWebTokenError: invalid signature • TokenExpiredError: jwt expired • JsonWebTokenError: jwt malformed / invalid token What ty...

In my Node.js application, I repeatedly encounter this error when making HTTP/HTTPS requests: Error: socket hang up code: 'ECONNRESET' This happens unexpectedly—sometimes with large payloads or multiple requests. Why does it occur, and how can I f...

In my Node.js app, memory usage steadily increases over time—even without increased load. Eventually, it crashes with an Out of Memory (OOM) error. What causes such memory leaks, and how can I detect and resolve them?

In my Node.js application, sometimes an asynchronous function (e.g. a file read or HTTP request) fails, and my app either crashes or silently ignores the error. Why does this happen and how can I prevent it?

How can I take a condition-based approach in a cross-plane composition?