Java – How to join List String with commas
In Java, we can use String.join(",", list) to join a List String with commas. We also can use Stream Collectors.joining or even in old days we create a custom method…
Jackson – How to parse JSON
Jackson provide writeValue() and readValue() methods to convert Java objects to / from JSON. mapper.writeValue – Java Objects to JSON. mapper.readValue – JSON to Java Objects.
Jackson 2 – Convert Java Object to / from JSON
In this tutorial, we will show you how to use Jackson 2.x to convert Java objects to / from a JSON: writeValue(...) – Java Objects to JSON , readValue(...) –…
Java 8 Stream.reduce() examples
In Java 8, the Stream.reduce() combine elements of a stream and produces a single value, with 2 arguments: 1 - identity is default or initial value, and 2 - BinaryOperator…
Java 8 – Stream Collectors groupingBy examples
In this article, we will show you how to use Java 8 Stream Collectors to group by, count, sum and sort a List, and also do a mapping.
How to print an Array in Java
In this article, we will show you a few ways to print a Java Array. We can use JDK 1.5 Arrays.toString to print a simple array and Arrays.deepToString for 2d…
Java – How to join Arrays
In this article, we will show you a few ways to join a Java Array: 1 - Apache Commons Lang – ArrayUtils, 2 - Java API, 3 - Java 8…
Java 8 flatMap example
This article explains the Java 8 Stream.flatMap and how to use it. In Java 8, we can use the flatMap to convert the above 2 levels Stream into one Stream…
Java 8 – Filter a Map examples
Few Java examples to show you how to filter a Map with Java 8 stream API. With Java 8, you can convert a Map.entrySet() into a stream, follow by a…
Java 8 Streams map() examples
In Java 8, stream().map() lets you convert an object to something else. Review the following examples : convert a list of Strings to upper case, get all the name values…