Why does @SafeVarargs not suppress the warning?

Question

Here is the code:

class Foo<T> {
  private final T[] array;
  @SafeVarargs
  Foo(T... items) {
    this.array = items;
  }
}

I get:

[WARNING] Varargs method could cause heap pollution 
from non-reifiable varargs parameter items

What happened to my assignment? How to fix it? @SuppressWarningsis not an option, as I want this constructor to be truly "safe".

$ javac -version
javac 1.8.0_40

Answer 1

My problem was that I used the -Xlintcommand line option javac. I found out that I need to compile it with the following parameters:

javac -Werror -Xlint -Xlint:-varargs

What is it.

Answer 2

Joshua Bloch explains this in Effective Java (chapter 25):

. , , ( . 29 ). , , varargs ( 42) . , , varargs, varargs. , . , ( 24), varargs API.

spec, , ( ArrayBuilder )

, SafeVarargs SuppressWarnings

@SafeVarargs
@SuppressWarnings( "varargs" )

Answer 3

docs:

arity (vararg) ,

, @SafeVarargs :

• varargs

@SafeVarargs T... items. this.array = items;.

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JLS §9.6.4.7:

@SafeVarargs , , arity.

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, @SuppressWarnings("unchecked") , , .