Interface is an integral part of java and has become so powerful over the years, that it shifted the way a Java programmer thinks.
To use the partitioningBy Collector, you have to pass the Collectors.partitioningBy in the collect() method of Stream API.
Before seeing Optional in Java, Did you know that Null Pointer Exception is termed as Billion Dollar mistake? Lets see how to avoid it.
Using Functional interfaces provided by Java we can become more functional. And Knowing them would help us utilise Stream API fully