Types of Methods in Java

So in Java there are many kinds of methods. I probably won’t even list half of them but I try to explain how different methods can be. Continue reading Types of Methods in Java

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Functions in Java

There’s a lot of confusion about “functions” in Java. Java doesn’t really have them, but an object could represent a function so it kind of does have them. I try to explain the different meanings of “functions” in Java, other languages and in mathematics.

Continue reading Functions in Java

Multiset in Java

Here’s an implementation of a multiset in Java 8. It uses a Map<T, Integer> to count how many times an object was inserted (multiplicity). It is not thread-safe, but there’s synchronizedMultiset(...) and it always knows the current size in O(1). With the method asMap() you can get a view of the multiset as a Map, that will allow modification of the underlying multiset.

The code is on GitHub: github.com/claudemartin/multiset

This started as a simple implementation and is not rather complex. The iterator allows to remove elements during iteration. I tried to write my own Spliterator, but it wasn’t faster than the default implementaion. Many methods are optimized and I added some set operations for multisets (union, intersect, minus). With merge(...) you can merge two multisets with any operation.