---
title: Java 10 
description:  JDK 10  var 
category: Java
tag:
  - Java
head:
  - - meta
    - name: keywords
      content: Java 10,JDK10,var ,,
---

**Java 10**  2018  3  20  LTSOracle 

 JDK 8  JDK 25 

![ JDK 8  JDK 25 ](https://oss.javaguide.cn/github/javaguide/java/new-features/jdk8~jdk24.png)



- [JEP 286: Local-Variable Type Inference](https://openjdk.org/jeps/286)
- [JEP 304: Garbage-Collector Interface](https://openjdk.org/jeps/304)
- [JEP 307: Parallel Full GC for G1G1  Full GC](https://openjdk.org/jeps/307)
- [JEP 310: Application Class-Data Sharing](https://openjdk.org/jeps/310)
- [JEP 317: Experimental Java-Based JIT Compiler Java  JIT ](https://openjdk.org/jeps/317)

## JEP 286: Local-Variable Type Inference

 Java  Java  Java 10 

Java 10  `var` 

```java
var id = 0;
var codefx = new URL("https://mp.weixin.qq.com/");
var list = new ArrayList();
var list = List.of(1, 2, 3);
var map = new HashMap();
var p = Paths.of("src/test/java/Java9FeaturesTest.java");
var numbers = List.of("a", "b", "c");
for (var n : numbers)
    System.out.print(n+ " ");
```

`var`  for 

```java
var count = null; // null
var r = () -> Math.random();// Lambda
var array = {1, 2, 3};//
```

`var`  Java 

Scala  Kotlin  `val`  ( `final var` )

## JEP 304: Garbage-Collector Interface

 JDK  (GC)  Java 10 

## JEP 307: Parallel Full GC for G1

 Java 9  G1 G1  Full GC Java 9  G1  Full GC  Full GC

 Full GC  Java10 G1  FullGC  Full GC 

## JEP 310: **( CDS )**

 Java 5  (Class Data Sharing CDS) Java  Java JVMCDS  Oracle JDK 

Java 10  CDS CDS  bootstrap  CDS  (Application Class-Data SharingAppCDS)  CDS 

## JEP 317: ** Java  JIT **

Graal  Java  JIT  JDK 9  Ahead-of-Time (AOT) 

Oracle  HotSpot VM  C++  JIT compilerC1  C2 Java 10 (Linux/x64, macOS/x64)  HotSpot  C2 java  `-XX:+UnlockExperimentalVMOptions -XX:+UseJVMCICompiler`  C2  Graal

## API 

 API  JEPJava Enhancement Proposal

 JDK **JEP**  `var` JVM  ZGC `List.copyOf()`  JDK  **JBS (JDK Bug System)** Ticket

### 

`List``Set``Map` `copyOf()`

```java
static  List copyOf(Collection