What does the arrow operator - do in Java

Question

While hunting through some code I came across the arrow operator  what exactly does it do  I thought Java did not have an arrow operator   return  Collection lt Car gt   CollectionUtils select listOfCars   arg0  - gt            return Car SEDAN      Car arg0  getStyle          Details  Java 6  Apache Commons Collection  IntelliJ 12   Update Answer  It turns out that IntelliJ 12 supports Java 8  which supports lambdas  and is  folding  Predicates and displaying them as lambdas  Below is the  un-folded  code   return  Collection lt Car gt   CollectionUtils select listOfCars  new Predicate         public boolean evaluate Object arg0            return Car SEDAN      Car arg0  getStyle

User · Answer

It s a lambda expression   It means that  from the listOfCars  arg0 is one of the items of that list  With that item he is going to do  hence the -   whatever is inside of the brackets   In this example  he s going to return a list of cars that fit the condition  Car SEDAN      Car arg0  getStyle

User · Answer

New Operator for lambda expression added in java 8  Lambda expression is the short way of method writing   It is indirectly used to implement functional interface  Primary Syntax    parameters  -    statements     There are some basic rules for effective lambda expressions writting which you should konw

User · Answer

That s part of the syntax of the new lambda expressions  to be introduced in Java 8  There are a couple of online tutorials to get the hang of it  here s a link to one  Basically  the - gt  separates the parameters  left-side  from the implementation  right side   The general syntax for using lambda expressions is  Parameters  - gt    Body   where the - gt  separates parameters and lambda expression body  The parameters are enclosed in parentheses which is the same way as for methods and the lambda expression body is a block of code enclosed in braces

User · Answer

I believe  this arrow exists because of your IDE  IntelliJ IDEA does such thing with some code  This is called code folding  You can click at the arrow to expand it

User · Answer

This one is useful as well when you want to implement a functional interface Runnable r     - gt  System out print  quot Run method quot     is equivalent to Runnable r   new Runnable              Override         public void run                 System out print  quot Run method quot

[java] What does the arrow operator, '->', do in Java?

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