Internal working of ArrayList: Source Code, Examples, and Practical Insights
Introduction In Java, collections are essential for handling dynamic data where the size of elements isn’t fixed at compile time. Arrays provide constant-time access, but they come with a limitation: fixed size. Once declared, the size of an array cannot be changed. That’s where ArrayList comes in — it combines the benefits of arrays (random access) with the flexibility of dynamic resizing. ArrayList is one of the most widely used classes in the Java Collections Framework (JCF) . It is part of the java.util package and is ideal for scenarios where frequent retrieval operations are more common than frequent insertions or deletions in the middle of the list. ArrayList Hierarchy in Collections Framework Here’s how ArrayList fits into the JCF hierarchy: java.lang.Object ↳ java.util.AbstractCollection<E> ↳ java.util.AbstractList<E> ↳ java.util.ArrayList<E> ArrayList implements List , RandomAccess , Cloneable , and Serializable . Array...