Docker Essentials
Foundation concepts every Java developer needs
38%
3/8 lessons
Lessons
What is Docker?
Introduction to containerization and Docker
Docker is a platform for developing, shipping, and running applications in containers. Containers are lightweight, standalone packages that include everything needed to run a piece of software: code, runtime, libraries, and settings.
Code Example
# Check Docker version
docker --version
# Run Hello World container
docker run hello-world
# List running containers
docker ps
# List all containers
docker ps -a
# List images
docker imagesKey Concepts
Consistency
Run the same container on dev, test, and production. No more "works on my machine" issues.
Isolation
Each container runs in its own isolated environment with separate filesystems and networking.
Portability
Build once, run anywhere. Local machine, cloud, or Kubernetes cluster.
Efficiency
Containers share the host OS kernel, making them lightweight compared to VMs.
Key Insight
Think of Docker containers as lightweight VMs that start in seconds and use a fraction of the resources. But unlike VMs, they share the host kernel.