Can you name books you have studied or used in your professional activity?

Here are some popular books on Java that are often studied and used in professional activities:

• "Java: The Complete Reference" by Herbert Schildt — an excellent introduction to the language.
• "Effective Java" by Joshua Bloch — a collection of best practices and recommendations for writing quality code.
• "Java Concurrency in Practice" by Brian Goetz — a deep understanding of multithreading in Java.
• "Head First Java" by Kathy Sierra and Bert Bates — a visual and accessible introduction to Java.

These books help understand both the basics of the language and advanced topics, which is useful for developing professional skills.