Hello guys, if you wonder how to remove duplicates from Stream in Java, don't worry. You can use the Stream.distinct() method to remove duplicates from a Stream in Java 8 and beyond. The distinct() method behaves like the distinct clause of SQL, which eliminates duplicate rows from the result set. The distinct() is also a standard method, which means it will return a new Stream without duplicates, which can be used for further processing. Like other methods of Stream class, I mean, map(), flatmap(), or filter(), distinct() is also lazy, and it will not remove duplicate elements until you call a terminal method on Streams like collect or forEach().
5 Examples of map() and flatMap() in Java 8 Stream
The map() and flatMap() are prince and princess of functional programming in Java. They are two powerful methods of Stream API which I believe every Java developer should be aware of and should also master it. You can use map() and flatMap() for data transformation, dealing with database operations where you need to convert one object to another while saving or reading from database. You can also use them for parsing and formatting as well as when you want to remove boiler plate code and make your data pipeline concise. The map() function is used in functional programming to transform each element of Stream into another element.
Java 8 Stream.filter() example Example with Null and Empty String
The filter() is a method on Stream class, which accepts a Predicate (a functional interface with a method which return boolean) and returns a stream consisting of the elements of this stream that match the given predicate. For example, if stream is obtained from a list containing "SONY", "APPLE" and "GOOGLE" and predicate is elements with length greater than 4, then filter will return another stream containing only APPLE and GOOGLE, leaving SONY out because its length is not greater than 4. Java 8 provides advanced filtering capability using lambdas and predicates.
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