How to translate java 8's lambda to java 7? [duplicate]

Question

In Java 8 we have lambdas like this one

a.sort((v1, v2) -> {});

How would this functionality be implemented in Java 7?

Answer 1

There are 2 differences between Java 7 and 8 relevant to this question.

1. In Java 7, List did not have a sort method. You had to use Collections.sort.
2. In Java 7, lambda expressions ( -> ) were not part of the language.

The Java 7 equivalent is

Collections.sort(list, new Comparator<Integer>() {
    @Override
    public int compare(Integer v1, Integer v2) {
        // Write what you need here.     
    }
});

Answer 2

It basically translates to this:

a.sort(new Comparator<T>(){
    public int compare(T v1, T v2){
        return 0;
    }
});

Java 8 introduced the "lambda" concept which allows you to eliminate the anonymous subclass syntax (among other things). You can read more about it here.