Java Lambda List To Map

Code with lambda expressions can be hard to understand. Similarly for set & map as well. First, let us convert list into map.

We have passed character and runnable arguments to map object and pass a lambda expression as the second argument in the put () method of map class. An attempt to modify such a collection would result in java.lang.unsupportedoperationexception runtime exception. Iterating map in java 8 using lambda expression

To avoid conflict of duplicate keys, we pass merge function otherwise it will throw illegalstateexception.

Java 8 i have already covered normal way of iterating map and list in java. Handling map values with lambda expressions consuming the content of a map the map interface has a foreach () method that works in the same way as the foreach () method on the iterable interface. Sometimes the method body is simply an expression, and sometimes it’s a full method body in curly braces. Map<long, string> map = users.stream ().collect (collectors.tomap (user::getid, user::getlastname));