### Java8

#### 1.Java 8 

```
1. Lambda 
2.  Stream API
3.  Optional  
4. 
5. 
6.  
7.  api
```

#### 2.   

```
 abstract  class         
   interface 

    jdk7
    jdk8   
    jdk9  private 

    
    

    

```

#### 3.Java8

Java 8java /

/

Java 8JavaJavaJava/

#### 4.Java 8

Java 8java.util.Optional isPresent

#### 5.hashMapjava8

HashMap++JDK1.8HashMapnullnullHashMapConcurrentHashMapmmTiT(i)Java88

#### 6.Java 8-



 -Stream

 -

#### 7.Lambda

Lambda ExpressionLambda

Lambda//lambda

#### 8.Lambda

Java 8 Java 8 

 n > System.out.printlnHello World+ n; 

Java 8 LambdaCPUlambdaCPU

#### 9.Java8MetaSpacePermGen Space

JDK8permGenMetaSpaceJavaPermGen

#### 10.Java SE 8

Java SE 8



#### 11.LambdaLambda

LambdaLambda->

#### 

https://blog.csdn.net/qq_37891300/article/details/82817900

https://blog.csdn.net/pzq915981048/article/details/89011881

https://www.cnblogs.com/jobbible/archive/2019/02/14/10374405.html