Useful links

Documentation

• Dev.java — Oracle's official Java learning materials
• Java SE Documentation — API reference, guides, and JDK tools for each version
• Java Language and Virtual Machine Specifications — formal descriptions of Java syntax and semantics
• JDK Enhancement Proposals — descriptions of new language features, including records and pattern matching

Tools and libraries

• IntelliJ IDEA documentation — working in the development environment, debugging, and refactoring code
• Git Reference Manual — the official command reference for the Git version control system
• Maven Documentation — guides to building projects and managing dependencies in Maven
• Gradle User Manual — configuring builds, dependencies, and tasks in Gradle
• JUnit User Guide — writing and running unit tests in JUnit
• OpenJFX Documentation — installing JavaFX and configuring projects in development environments
• Scene Builder — a visual FXML editor for designing JavaFX interfaces

Databases

• JDBC API (java.sql) — the Connection, PreparedStatement, and ResultSet interfaces for database access
• PostgreSQL JDBC Driver — connecting to PostgreSQL from Java and configuring driver parameters
• PostgreSQL Documentation — SQL, data types, and features of the PostgreSQL database management system

Tutorials and practice

• Baeldung Java Tutorial — articles with examples on the language, collections, the Stream API, and testing
• Jenkov Java Tutorials — sequential tutorials on Java, collections, NIO, and JDBC
• Java Programming MOOC — a free University of Helsinki course with exercises from fundamentals to OOP
• Learn Git Branching — interactive exercises on branches, merging, and rebasing in Git

Community, blogs, and videos

• Inside.java — news, articles, and podcasts from Java developers at Oracle
• Java YouTube channel — overviews of new Java releases, talks, and video tutorials