Initialize array in method argument

Question

In PHP you can do the following:

method(array("a", "b"));

Can you in Java initialize a String array as an argument in the method call, something like tihs:

method(new String[] = {"a", "b"});

Thanks!

Answer 1

Java has an equivalent construct:

import java.util.Arrays;

public class Foo {
   public void method(String[] myStrArray) {
      System.out.println(Arrays.toString(myStrArray));
   }

   public static void main(String[] args) {
      Foo foo = new Foo();
      foo.method(new String[]{"hello", "goodbye"}); // **array created inline**
   }
}

Answer 2

@Hovercraft's answer shows how to create an array inline in Java.

You could further improve on that solution by using an utility method (one that makes use of Java's limited type inference) to get rid of the redundant array type annotation.

Code:

import java.util.Arrays;

// Utility class
class Array {
  public static <A> A[] of(A ... elements) {
    return elements;
  }
}

// Main class
class Main {
  public static void method(String[] s) {
    System.out.println(Arrays.toString(s));
  }

  public static void main(String[] args) {
    method(Array.of("a", "b", "c"));
  }
}

Answer 3

Java has varargs methods:

public void foo(String ... args){
    for(String arg : args){
        // do something
    }
}

You can call such a method with zero to n parameters, the compiler creates an array from the parameters, e.g. the method is equivalent to this Signature:

public void foo(String[] args)

Answer 4

No

But we have anonymous class.

foo(new Runnable(){public void run(){}});