Java

Core Java, object oriented programming, collections, multithreading and JDBC.

100 notes in 18 topics

Topics in Java

Java

Serialization turns an object graph into bytes and back. It is easy to switch on, hard to maintain, and a genuine security risk.

Java

A thread is an independent path of execution inside one process, and Java gives you several ways to start one.

Java

A thread moves through six states, and knowing which one it is in is the first step in diagnosing any hang.

Java

synchronized gives mutual exclusion and visibility. volatile gives visibility only, and knowing the difference prevents most concurrency bugs.

Java

Explicit locks offer timeouts, fairness and multiple conditions, and the atomic classes give lock free updates for single variables.

Java

The two failures that define concurrency: results that depend on timing, and threads that wait for each other forever.

Java

An executor separates submitting work from running it, so threads are reused instead of created per task.

Java

A Future is a placeholder for a result that is not ready yet. CompletableFuture adds composition, so results can be chained without blocking.

Java

Purpose built collections for shared access, which are both safer and far faster than wrapping an ordinary one in a lock.

Java

The rules that decide when a write by one thread becomes visible to another, expressed as the happens-before relationship.

Java

The class loader, the runtime data areas and the execution engine, and how a class file becomes running machine code.

Java

Classes are found, verified, prepared and initialised on first use, by a hierarchy of loaders that delegate upwards.