Author Archives: Stanislav_Panteleev

Let’s talk about why Java uses padding in memory layout — even when you only store something tiny like a byte.

Let’s estimate how much memory is needed to store a single byte primitive in a Java LinkedList<Byte>. Even though it’s “just a byte” (which is 1 byte!), the actual memory cost in a LinkedList<Byte> is much higher because of: Boxing … Continue reading →

Every object in Java has an object header — a block of metadata that the JVM attaches to every object on the heap.

In Java, a LinkedList is a doubly-linked list, meaning each element is stored in a node object like this: So every time you call add(), the list creates a new Node object to hold the element.

✅ Normal case (no resize) And the internal array still has room, the memory cost is: 💾 Only the reference to the new element is added (e.g., 4 or 8 bytes depending on JVM architecture). So: No new array allocation … Continue reading →

If you want to efficiently remove several adjacent elements from the middle of an ArrayList, there’s a much better way than calling remove(index) in a loop.

Let’s break down exactly how elements are removed from an ArrayList, and how that affects its size and internal structure.

When you need to add 1 million elements, the best choice depends on where and how you’re adding them.

Let’s dive into the worst-case time complexity of the add() method for ArrayList.

Let’s explore the worst-case running time of the add() method in a LinkedList—and clarify which version of add() we mean: