Why does a Java Lambda which throws a Runtime Exception require brackets?

by

The Java Language Specification describes the body of a lambda expression

A lambda body is either a single expression or a block (ยง14.2).

This, however, 

throw new IllegalArgumentException("fail")

is the throw statement, not an expression. The compiler therefore rejects it as the lambda expression’s body.

You can go down the rabbit hole and learn what all the types of expressions are, here (follow the grammar).

More Related Contents:

  1. Why can’t I throw an exception in a Java 8 lambda expression? [duplicate]
  2. Java 8 List into Map
  3. Comparator.reversed() does not compile using lambda
  4. Java8 Lambdas vs Anonymous classes
  5. Java 8: Lambda-Streams, Filter by Method with Exception
  6. What is a ‘SAM type’ in Java?
  7. What is the breakdown for Java’s lambda syntax?
  8. LambdaConversionException with generics: JVM bug?
  9. Java 8 method reference unhandled exception
  10. How do I define a method which takes a lambda as a parameter in Java 8?
  11. Lambda expression and method overloading doubts
  12. Java 8 chained method reference?
  13. Why are Java 8 lambdas invoked using invokedynamic?
  14. Why do Consumers accept lambdas with statement bodies but not expression bodies?
  15. How to dynamically do filtering in Java 8?
  16. Do lambda expressions have any use other than saving lines of code?
  17. Java 8 Supplier with arguments in the constructor
  18. What is a Java 8 Lambda Expression Compiled to? [duplicate]
  19. Why does Stream.allMatch() return true for an empty stream?
  20. Java idiom for lambdas with non-SAM interfaces
  21. Local variable log defined in an enclosing scope must be final or effectively final
  22. Java access bean methods with LambdaMetafactory
  23. Implement recursive lambda function using Java 8
  24. What kind of List does Collectors.toList() return?
  25. Proper usage of Optional.ifPresent()
  26. java: Arrays.sort() with lambda expression
  27. Implied anonymous types inside lambdas
  28. Purpose of third argument to ‘reduce’ function in Java 8 functional programming
  29. Are Java 8 lambdas compiled as inner classes, methods or something else? [duplicate]
  30. Java 8 lambda for selecting top salary employee for each department

Leave a Comment