JDK9 REPL

I have been building and quickly exploring various JDK 9 features during this past weekend.
There is a new REPL now among other gems. I will update this post as I explore it further.

Mohans-MacBook-Pro:openjdk radhakrishnan$ java -version
java version “1.9.0-ea”
Java(TM) SE Runtime Environment (build 1.9.0-ea-b61)
Java HotSpot(TM) 64-Bit Server VM (build 1.9.0-ea-b61, mixed mode)
Mohans-MacBook-Pro:openjdk radhakrishnan$ java -jar kulla-0.508-20150510054454.jar
| Welcome to JShell — Version 0.508
| Type /help for help

->

-> String s = “__mainn__”.replaceAll(“[^a-z\\s]”, “”);
| Added variable s of type String with initial value “mainn”

-> System.out.println(s);

-> mainn

-> final Map count = s.chars().map(Character::toLowerCase).collect(TreeMap::new, (m, c) -> m.merge((char) c, 1, Integer::sum), Map::putAll);
| Warning:
| Modifier ‘final’ not permitted in top-level declarations, ignored
| final Map count = s.chars().map(Character::toLowerCase).collect(TreeMap::new, (m, c) -> m.merge((char) c, 1, Integer::sum), Map::putAll);
| ^—^
| Added variable count of type Map with initial value {a=1, i=1, m=1, n=2}

-> int x = 26;
| Added variable x of type int with initial value 26

-> count.entrySet().stream().sorted((l, r) -> r.getValue().compareTo(l.getValue())).forEach(e -> count.merge(e.getKey(), x–, Math::multiplyExact));

-> System.out.println(count.entrySet().stream());
java.util.
-> stream.ReferencePipeline$Head@548a9f61

-> System.out.println(count.entrySet().stream().mapToDouble(e -> e.getValue()).sum());
124.0

Everything can be changed in the REPL. Nothing is final and it is ignored. That is what kulla-dev@openjdk.java.net told me.

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