---
title: Java 10 
category: Java
tag:
  - Java
---

**Java 10**  2018  3  20  `var` GC 

**** 

- [JEP 286](https://openjdk.java.net/jeps/286)
- [JEP 304](https://openjdk.java.net/jeps/304)
- [JEP 307G1  Full GC](https://openjdk.java.net/jeps/307)
- [JEP 310( CDS )](https://openjdk.java.net/jeps/310)
- [JEP 317 Java  JIT ](https://openjdk.java.net/jeps/317)

## (var)

 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 : list)
    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` )

[Java 10 ](https://zhuanlan.zhihu.com/p/34911982)

## 

 JDK  (GC)  Java 10 

## G1  Full GC

 Java9  G1 G1  Full GC, Java9  G1  FullGC , Full GC

 Full GC  Java10 G1  FullGC  Full GC 

## 

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

```java
static  List copyOf(Collection