javamongojack

What does <> in Java mean?

Looking at a library called mongojack 3.0 - https://github.com/mongojack/mongojack. This library contains a file called JacksonMongoCollection.java It has a method...

  public JacksonCollectionKey<TResult> getCollectionKey() {
        return new JacksonCollectionKey<>(getMongoCollection().getNamespace().getDatabaseName(), getMongoCollection().getNamespace().getCollectionName(), getValueClass());
    }

This returns JacksonCollectionKey<>

This library compiles fine.

I have not seen an empty generic type definition before. How does this work?

Solution

  • Empty generic type brackets are used where generic type can be inferred from context by compiler. In your case, compiler will insert TResult into empty brackets.