Why I can call non-static method length() from class String, but I can’t call non-static method lengthHelper( String line ) from my class ExpressionHelper? Answer String::length is an instance method of String. It requires an instance of String to run, which you are providing, because you are passing elements of lines1 to it. ExpressionHelper::lengthHelper is an instance method of ExpressionHelper.
Tag: lambda
Mapping pair of elements into one with Stream IPA
So I’m wondering what is the best solution to the following problem: I have a list of items (a custom class) in a java collection ex Each item in the collection however has a corresponding logical pair also in the collection (so the pair’s are not necessarily following each other by index in the collection) I have a helper method
reusing stream inside a stream java
Hi I just wanted to know what is wrong with my code and how can I improve it as it throws an error “stream has already been operated upon or closed” thank you here is my code: I wanted to loop inside the file and check per line if the characters there exceeded 12 characters or not Answer You cannot
Replace class methods with lambda expressions, is it bad practice?
I had a few questions that I’m having trouble finding the answer to, at least in Java. I saw a Class definition in a tutorial where lambdas were being used similar to methods. So I’m curious as to if there is any benefit apart from concise code and style preference. Example: Is this a valid class definition? Is this a
how to add synchronization in following lambda exp?
Can synchronized blocks be used for some of the code blocks written in lambda expression . With respect to the following code snippet : Answer It is possible to use synchronized blocks inside a Java Lambda Expression and inside anonymous classes. Note: You have forgotten to add code snippet as no code snippet is visible in your code , So
Spark Dataset Foreach function does not iterate
Context I want to iterate over a Spark Dataset and update a HashMap for each row. Here is the code I have: Issue My issue is that the foreach doesn’t iterate at all, the lambda is never executed and I don’t know why. I implemented it as indicated here: How to traverse/iterate a Dataset in Spark Java? At the end,
Trying to mimic java functional interface
I am trying to mimic the java’s Function<T,R> by writing below code : when I am writing below code in andThen, it’s working fine (pointing to apply(T t) of interface) and perfectly chaining the other functional implementations But when writing below snippet, it’s falling into recursion, logically that’s correct , but why in snippet A, after.apply(apply(t)) is calling outer apply(T
How can I avoid null using lambda in this case?
The following method you have seen returns all the information of the user in the database according to the phone number as follows. However, when I perform an operation based on a phone number that is not in the database, it still returns the second part instead of this message. But I want it to look like this in the
Can I use a lambda function like this?
I want to try to use lambda functions (which I do not understand well) so I can learn more about them. I have an assignment on trees that has us making a family tree class. children is a set of all of the children nodes to this node. Also as a side question, does this usage of AtomicInteger work similarly
Java does not catch exception
I am trying to implement lambda expression for constructor. My constructor can throw an IllegalArgumentException. I tried different ways. First way is just calling lambda expression: It works perfectly fine, I can catch Exception and then parse it. The problem occurs when I try to use my own interface: and then I use it as: But the last line of