diamond-operator

Java 7 has improved the diamond operator In Java 6 Map<String, String> myMap = new HashMap<String, String>(); In Java 7 Map<String, String> myMap = new HashMap<>(); In Java 7 Types have been removed from diamond operator on Right hand side(RHS). My question why don't remove complete diamond operate from RHS. I know it will throw the warning, But java 7 could have removed the warning also. - Type safety: The expression of type HashMap needs unchecked conversion to conform to Map<String,String> - HashMap is a raw type. References to generic type HashMap<K,V> should be parameterized Logic behind

This question already has an answer here: What is the point of the diamond operator (<>) in Java 7? 7 answers I'm using Android Studio and I write this : List<Button> buttons = new ArrayList<Button>(); I have this message : Explicit type argument Button should be replaced by <> I'm curious, why would it be better to use diamond instead ? List<Button> buttons = new ArrayList<>(); EDIT : I don't agree with the duplicate at all ! I saw that answer before and it compares explicit argument to no argument at all, whereas I compare explicit argument to implicit argument ! It is less verbose, consider

Code $ cat test1 hello i am lazer nananana $ cat 1.pl use strict; use warnings; my @fh; open $fh[0], '<', 'test1', or die $!; my @res1 = <$fh[0]>; # Way1: why does this not work as expected? print @res1."\n"; my $fh2 = $fh[0]; my @res2 = <$fh2>; # Way2: this works! print @res2."\n"; Run $ perl 1.pl 1 5 $ I am not sure why Way1 does not work as expected while Way2 does. Aren't those two methods the same? What is happening here? Because of the dual nature of the <> operator (i.e. is it glob or readline ?), the rules are that to behave as readline, you can only have a bareword or a simple scalar