Can the below function be less verbose with a Lambda expression? How can I trim it down? It is calling the FilenameFilter.accept() Java method. Answer I’m not certain about the Kotlin syntax, but you can certainly trim it down by returning the boolean expression directly, eliminating the if: I believe t…
Tag: lambda
Java access bean methods with LambdaMetafactory
my question is strongly related to Explicit use of LambdaMetafactory in that thread, some very good examples are provided to use the LambdaMetafactory to access a static method of a class; however, I wonder what is the equivalent code to access a non static field of an existing bean instance. It seems really …
Java 8 stream map on entry set
I’m trying to perform a map operation on each entry in a Map object. I need to take a prefix off the key and convert the value from one type to another. My code is taking configuration entries from a Map<String, String> and converting to a Map<String, AttributeType> (AttributeType is just a …
Are lambdas garbage collected?
If I’m not mistaken, under certain situations a lambda in Java is generated as an anonymous class instance. For example, in this code the lambda needs to capture a variable from the outside: Does it means that the garbage collector will claim the lambda as an object? Answer No it won’t; this is no…
Possibility to explicit remove Serialization support for a lambda
As already known it’s easy to add Serialization support to a lambda expression when the target interface does not already inherit Serializable, just like (TargetInterface&Serializable)()->{/*code*/}. What I ask for, is a way to do the opposite, explicitly remove Serialization support when the target in…
Iterate an Enumeration in Java 8
Is it possible to iterate an Enumeration by using Lambda Expression? What will be the Lambda representation of the following code snippet: I didn’t find any stream within it. Answer In case you don’t like the fact that Collections.list(Enumeration) copies the entire contents into a (temporary) list befo…
Java8 Lambdas vs Anonymous classes
Since Java8 has been recently released and its brand new lambda expressions looks to be really cool, I was wondering if this means the demise of the Anonymous classes that we were so used to. I’ve been researching a bit about this and found some cool examples about how Lambda expressions will systematic…
How do I use the new computeIfAbsent function?
I very much want to use Map.computeIfAbsent but it has been too long since lambdas in undergrad. Almost directly from the docs: it gives an example of the old way to do things: And the new way: But in their example, I think I’m not quite “getting it.” How would I transform the code to use th…
Java 8: Where is TriFunction (and kin) in java.util.function? Or what is the alternative?
I see java.util.function.BiFunction, so I can do this: What if that is not good enough and I need TriFunction? It doesn’t exist! I guess I should add that I know I can define my own TriFunction, I’m just trying to understand the rationale behind not including it in the standard library. Answer As …