Features Added:
- Records: The record is a new type of class in Java that makes it easy to create immutable data objects. It was introduced in Java 14. Java 15 aims to refine a few aspects before becoming an official product feature. The class definition has a new syntax that is specific for records, allow us to override some of the default behaviors.
- Sealed Classes: Java provides no fine-grained control over the inheritance. Sealed classes involve two new keywords — sealed and permits. These are to allow individual classes to declare which types may be used as sub-types. This also applies to interfaces and determining which types can implement them. Any class that extends a sealed class must itself be declared sealed, non-sealed, or final.
- Hidden Classes: It is to allow the runtime creation of classes that are not discoverable.
- Pattern Matching Type Checks: Here got few enhancement top of Java 14. The goal of this feature is to remove a lot of boilerplate code that typically comes with the instanceof operator.
- Foreign Memory API: Foreign memory generally refers to memory that lives outside the managed JVM heap. Because of this, it's not subject to garbage collection and can typically handle incredibly large memory segments. A new VarHandle API, to customize memory access var handles. Support for parallel processing of a memory segment using the Spliterator interface. Enhanced support for mapped memory segments. Ability to manipulate and dereference addresses coming from things like native calls.
- Garbage Collectors: In Java 15, both ZGC and Shenandoah will be no longer be experimental. Both will be supported configurations that teams can opt to use, while the G1 collector will remain the default. | Features Added:
- Vector API: Java supports auto-vectorization to optimize the arithmetic algorithms, which means the Java (JIT compiler) will transform some scalar operations (one item at a time) into vector operations (multiple items at a time) automatically. Developers have no control of this vector operation conversion, it totally depends on the JIT compiler to optimize the code.
- Enable C++14 Language: It allows the C++14 language features to be used in the C++ source code within the JDK.
- Migrate from Mercurial to Git: Migrates the OpenJDK source code from Mercurial to Git or GitHub.
- Concurrent Thread-Stack Processing: It improves the Z Garbage Collector (ZGC) by moving the ZGC thread-stack processing from safepoints to a concurrent phase.
- Unix-Domain Socket Channels: The Unix-domain sockets are used for inter-process communication (IPC) on the same host, which means exchanging data between processes executing on the same host. New Unix-domain Socket classes or APIs added (New socket address class, java.net.UnixDomainSocketAddress, New enum, java.net.StandardProtocolFamily.UNIX).
- Alpine Linux Port: This JEP port the JDK to Alpine Linux and other Linux distributions that use musl implementation. This JDK port enables Java to run out-of-the-box in Alpine Linux, which benefits those Java-dependent frameworks or tools like Tomcat and Spring.
- Elastic Metaspace: Java 8 JEP 122 removed the PermGen (Permanent Generation) and introduced Metaspace, a native off-heap memory manager in the hotspot. Java 16 improves the metaspace memory management by returning unused HotSpot class-metadata or metaspace memory to the operating system more promptly, reducing the metaspace footprint, and simplifying the metaspace code.
- Windows/AArch64 Port: This port the JDK to Windows/AArch64, running JDK + Windows on ARM hardware, server, or ARM-based laptop.
- Foreign Linker API: Enables Java code to call or can be called by native code written in o |
