What are the key differences between Java versions (7, 11, 17, 21)?

Java 7, 11, 17, and 21 are important releases with various improvements and new features:

• Java 7 (2011):

  • Introduction of try-with-resources for automatic resource management.
  • Enhancements in multithreading (Fork/Join Framework).
  • Support for dynamic languages (InvokeDynamic).

• Java 11 (2018, LTS):

  • Removal of deprecated modules (e.g., Java EE and CORBA).
  • Built-in HTTP Client API for easier HTTP operations.
  • New methods in String, Files, and other classes.
  • Support for running single-line Java scripts.

• Java 17 (2021, LTS):

  • Introduction of sealed classes to restrict inheritance.
  • Pattern Matching for instanceof.
  • Improvements in text handling (Text Blocks).
  • New APIs and performance enhancements.

• Java 21 (2023, LTS):

  • Continued development of pattern matching (pattern matching for switch).
  • Virtual threads (Project Loom) for simplifying multithreading.
  • Improvements in working with structured data and Record Patterns.

Each version brings improvements in development convenience, performance, and security, with LTS versions (11, 17, 21) recommended for production use.