From List To Map Java 8

Create a list of movies and convert with to map with name as key and genre as value. It throws illegalstateexception which is expected since key of a map should be unique. We will create person class & we will convert list of person objects to/from map.

To avoid conflict of duplicate keys, we pass merge function otherwise it will throw illegalstateexception. We need to pass mapping function for key and value. In this tutorial you will learn about how to convert list to map using java 8 collectors.tomap() api.

Create a class named convertlisttomapmain java output:

But in this article i will show you how to convert list to map using java 8 lambda expression. We can also use method references instead of lamda expressions. We will cover below examples for java 8 list to map conversion, id can be chosen as key and any other attribute like name can selected for value again id can be chosen as key and whole object as value what happens, if there are duplicate keys while converting list to map solution for duplicate keys, if duplicate objects present in list Then we will use the reduce function to get the current map and the map that has been constructed till now, or the accumulator map.