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By Greg Luck

Chief Technical Officer

Greg Luck is a leading technology entrepreneur with more than 15 years of experience in high-performance in-memory computing. He is the founder and inventor of Ehcache, a widely used open source Java distributed cache that was acquired by Software AG (Terracotta) in 2009, where he served as CTO. Prior to that, Greg was the Chief Architect at Australian start-up Wotif.com that went public on the Australian Stock Exchange (ASX:WTF) in 2006. Greg is a current member of the Java Community Process (JCP) Executive Committee, and since 2007 has been the Specification Lead for JSR 107 (Java Specification Requests) JCACHE. Greg has a master's degree in Information Technology from Queensland University of Technology and a Bachelor of Commerce from the University of Queensland.

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Oct 31, 2013

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Lambda Hello World

I was recently checking Lambda expressions out to ensure the forthcoming JCache spec would work well with them. I just wanted a really simple example that worked through the different syntactical forms and ended up putting a Hello World type example myself.

/**
 * Hello world!
 */
public class App {
  static void print(Something something) {
    System.out.println(something.doSomeThing("Hello World"));
  }
     @FunctionalInterface
  interface Something {
    String doSomeThing(String word);
  }
  public static void main(String[] args) {
    print(new Something() {
      @Override
      public String doSomeThing(String word) {
        return word.concat(" - it is no fun to AnonymousInnerClass");
      }
    });
    //expression form. No return
    print((String s) -> s.concat(" = it is fun to Lambda"));
    //block. Need return as interface method has return.
    print((String s) -> {return s.concat(" = it is fun to Lambda");});
    //expression. No type required as Interface defines it.
    print((s) -> s.concat(" = it is fun to Lambda"));
    //creating a concrete instance of a functional interface via assignment
    Something something = (s) -> s.replace("the", "thee");
    System.out.println(something.doSomeThing("What the!"));
    java.util.function.Predicate predicate = new
  }
}