Latest Non-LTS JDK Version: JDK 23
JDK 23 is the latest non-LTS (Long-Term Support) version of Java, introducing multiple new features. It provides cutting-edge enhancements but does not come with the long-term support that LTS versions receive.
Key Features of JDK 23
Unnamed Classes and Instance Main Methods
- Simplifies the creation of ad-hoc classes.
- Streamlines the entry point of Java applications by allowing unnamed classes and instance methods as entry points.
Deprecation of the Security Manager for Removal
- The Security Manager is marked for future removal, as it is considered outdated.
- Developers are encouraged to adopt more modern security practices.
Simplification of JDK Incubator Modules
- Introduces incubator modules that let developers experiment with new features before they become standard in future versions.
Latest LTS JDK Version: JDK 21
JDK 21 is the latest Long-Term Support (LTS) version of Java. LTS versions are supported for a minimum of 8 years, offering free updates and security patches during that period. JDK 21 includes several new features that improve the language and performance.
Key Features of JDK 21
Pattern Matching for Switch
- Simplifies code involving
switch statements.
- Eliminates the need for value boxing, making the code cleaner and more efficient.
Unnamed Classes and Instance Main Methods
- As seen in JDK 23, this feature allows for the easy creation of unnamed classes.
- Enables the use of instance methods for application entry points.
Scoped Values
- Introduces a mechanism to encapsulate and manage values within a specific scope.
- Enhances data security and concurrency.
JEP 446: Unnamed Variables
- Introduces unnamed variables (
_ underscore).
- Useful for discarding unnecessary values and reducing boilerplate code.
JEP 451: Restrict Dynamic Loading of Java Agents
- Restricts the dynamic loading of Java agents into running JVM processes.
- Improves security by controlling when and how agents are loaded into production environments.
Project Loom (Introduced in JDK 21)
Project Loom is a significant enhancement to Java, designed to simplify and improve multithreading and concurrency.
Key Features of Project Loom
Virtual Threads (Lightweight Threads)
- Virtual threads are managed by the JVM.
- Allows for a massive number of threads to be created with minimal memory overhead, enabling millions of threads to run efficiently.
Better Performance for Blocking Calls
- Virtual threads make blocking calls (e.g.,
Thread.sleep(), Socket.read(), or database queries) much more efficient.
- Reduces the need for excessive OS thread usage.
Improved Thread Management
- Virtual threads do not require large thread pools.
- The JVM maps many virtual threads to a few platform threads and handles them automatically.
Feature Comparison Table
| Feature | Traditional Threads | Virtual Threads (Project Loom) |
|---|
| Thread Creation | Heavy (OS thread 1MB) | Lightweight (JVM-managed) |
| Concurrency Limit | Limited by CPU cores | Millions of virtual threads possible |
| Memory Usage | High | Low |
| Performance | Slower (due to blocking) | Faster, better for IO-bound tasks |
| Scalability | Limited (due to thread pool size) | Highly scalable |
