Re: About the native-lambda branch

[Jochen Theodorou]

this looks quite promising

On 13.01.2018 12:24, Daniel Sun wrote:

Hi Jochen,

      Here is an example:

```
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class Test1 {
     public static void main(String[] args) {
         p();
     }

     public static void p() {
          Stream.of(1, 2, 3).map(e -> e + 1).collect(Collectors.toList());
     }
}
```

Its bytecode is shown as follows, note `  public final static INNERCLASS
java/lang/invoke/MethodHandles$Lookup java/lang/invoke/MethodHandles
Lookup`, which I found is useless, so I removed it and all code works still
well.

```
// class version 52.0 (52)
// access flags 0x21
public class Test1 {

   // compiled from: Test1.java
   // access flags 0x19
   public final static INNERCLASS java/lang/invoke/MethodHandles$Lookup
java/lang/invoke/MethodHandles Lookup

   // access flags 0x1
   public <init>()V
    L0
     LINENUMBER 4 L0
     ALOAD 0
     INVOKESPECIAL java/lang/Object.<init> ()V
     RETURN
     MAXSTACK = 1
     MAXLOCALS = 1

   // access flags 0x9
   public static main([Ljava/lang/String;)V
    L0
     LINENUMBER 6 L0
     INVOKESTATIC Test1.p ()V
    L1
     LINENUMBER 7 L1
     RETURN
     MAXSTACK = 0
     MAXLOCALS = 1

   // access flags 0x9
   public static p()V
    L0
     LINENUMBER 10 L0
     ICONST_3
     ANEWARRAY java/lang/Integer
     DUP
     ICONST_0
     ICONST_1
     INVOKESTATIC java/lang/Integer.valueOf (I)Ljava/lang/Integer;
     AASTORE
     DUP
     ICONST_1
     ICONST_2
     INVOKESTATIC java/lang/Integer.valueOf (I)Ljava/lang/Integer;
     AASTORE
     DUP
     ICONST_2
     ICONST_3
     INVOKESTATIC java/lang/Integer.valueOf (I)Ljava/lang/Integer;
     AASTORE
     INVOKESTATIC java/util/stream/Stream.of
([Ljava/lang/Object;)Ljava/util/stream/Stream;
     INVOKEDYNAMIC apply()Ljava/util/function/Function; [
       // handle kind 0x6 : INVOKESTATIC

java/lang/invoke/LambdaMetafactory.metafactory(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodHandle;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite;

       // arguments:
       (Ljava/lang/Object;)Ljava/lang/Object;,
       // handle kind 0x6 : INVOKESTATIC
       Test1.lambda$p$0(Ljava/lang/Integer;)Ljava/lang/Integer;,
       (Ljava/lang/Integer;)Ljava/lang/Integer;
     ]
     INVOKEINTERFACE java/util/stream/Stream.map
(Ljava/util/function/Function;)Ljava/util/stream/Stream;
     INVOKESTATIC java/util/stream/Collectors.toList
()Ljava/util/stream/Collector;
     INVOKEINTERFACE java/util/stream/Stream.collect
(Ljava/util/stream/Collector;)Ljava/lang/Object;
     POP
    L1
     LINENUMBER 11 L1
     RETURN
     MAXSTACK = 4
     MAXLOCALS = 0

   // access flags 0x100A
   private static synthetic
lambda$p$0(Ljava/lang/Integer;)Ljava/lang/Integer;
    L0
     LINENUMBER 10 L0
     ALOAD 0
     INVOKEVIRTUAL java/lang/Integer.intValue ()I
     ICONST_1
     IADD
     INVOKESTATIC java/lang/Integer.valueOf (I)Ljava/lang/Integer;
     ARETURN
     MAXSTACK = 2
     MAXLOCALS = 1
}

```

Cheers,
Daniel.Sun



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